lightnvm: physical block device (pblk) target

This patch introduces pblk, a host-side translation layer for
Open-Channel SSDs to expose them like block devices. The translation
layer allows data placement decisions, and I/O scheduling to be
managed by the host, enabling users to optimize the SSD for their
specific workloads.

An open-channel SSD has a set of LUNs (parallel units) and a
collection of blocks. Each block can be read in any order, but
writes must be sequential. Writes may also fail, and if a block
requires it, must also be reset before new writes can be
applied.

To manage the constraints, pblk maintains a logical to
physical address (L2P) table,  write cache, garbage
collection logic, recovery scheme, and logic to rate-limit
user I/Os versus garbage collection I/Os.

The L2P table is fully-associative and manages sectors at a
4KB granularity. Pblk stores the L2P table in two places, in
the out-of-band area of the media and on the last page of a
line. In the cause of a power failure, pblk will perform a
scan to recover the L2P table.

The user data is organized into lines. A line is data
striped across blocks and LUNs. The lines enable the host to
reduce the amount of metadata to maintain besides the user
data and makes it easier to implement RAID or erasure coding
in the future.

pblk implements multi-tenant support and can be instantiated
multiple times on the same drive. Each instance owns a
portion of the SSD - both regarding I/O bandwidth and
capacity - providing I/O isolation for each case.

Finally, pblk also exposes a sysfs interface that allows
user-space to peek into the internals of pblk. The interface
is available at /dev/block/*/pblk/ where * is the block
device name exposed.

This work also contains contributions from:
  Matias Bjørling <matias@cnexlabs.com>
  Simon A. F. Lund <slund@cnexlabs.com>
  Young Tack Jin <youngtack.jin@gmail.com>
  Huaicheng Li <huaicheng@cs.uchicago.edu>
Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <matias@cnexlabs.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

Documentation/lightnvm/pblk.txt

+pblk: Physical Block Device Target
+==================================
+
+pblk implements a fully associative, host-based FTL that exposes a traditional
+block I/O interface. Its primary responsibilities are:
+
+  - Map logical addresses onto physical addresses (4KB granularity) in a
+    logical-to-physical (L2P) table.
+  - Maintain the integrity and consistency of the L2P table as well as its
+    recovery from normal tear down and power outage.
+  - Deal with controller- and media-specific constrains.
+  - Handle I/O errors.
+  - Implement garbage collection.
+  - Maintain consistency across the I/O stack during synchronization points.
+
+For more information please refer to:
+
+  http://lightnvm.io
+
+which maintains updated FAQs, manual pages, technical documentation, tools,
+contacts, etc.

drivers/lightnvm/Kconfig

@@ -33,4 +33,13 @@ config NVM_RRPC
 	host. The target is implemented using a linear mapping table and
 	cost-based garbage collection. It is optimized for 4K IO sizes.
 
+config NVM_PBLK
+	tristate "Physical Block Device Open-Channel SSD target"
+	---help---
+	Allows an open-channel SSD to be exposed as a block device to the
+	host. The target assumes the device exposes raw flash and must be
+	explicitly managed by the host.
+
+	Please note the disk format is considered EXPERIMENTAL for now.
+
 endif # NVM

drivers/lightnvm/Makefile

@@ -4,3 +4,8 @@
 
 obj-$(CONFIG_NVM)		:= core.o
 obj-$(CONFIG_NVM_RRPC)		+= rrpc.o
+obj-$(CONFIG_NVM_PBLK)		+= pblk.o
+pblk-y				:= pblk-init.o pblk-core.o pblk-rb.o \
+				   pblk-write.o pblk-cache.o pblk-read.o \
+				   pblk-gc.o pblk-recovery.o pblk-map.o \
+				   pblk-rl.o pblk-sysfs.o

drivers/lightnvm/pblk-cache.c

+/*
+ * Copyright (C) 2016 CNEX Labs
+ * Initial release: Javier Gonzalez <javier@cnexlabs.com>
+ *                  Matias Bjorling <matias@cnexlabs.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * pblk-cache.c - pblk's write cache
+ */
+
+#include "pblk.h"
+
+int pblk_write_to_cache(struct pblk *pblk, struct bio *bio, unsigned long flags)
+{
+	struct pblk_w_ctx w_ctx;
+	sector_t lba = pblk_get_lba(bio);
+	unsigned int bpos, pos;
+	int nr_entries = pblk_get_secs(bio);
+	int i, ret;
+
+	/* Update the write buffer head (mem) with the entries that we can
+	 * write. The write in itself cannot fail, so there is no need to
+	 * rollback from here on.
+	 */
+retry:
+	ret = pblk_rb_may_write_user(&pblk->rwb, bio, nr_entries, &bpos);
+	if (ret == NVM_IO_REQUEUE) {
+		io_schedule();
+		goto retry;
+	}
+
+	if (unlikely(!bio_has_data(bio)))
+		goto out;
+
+	w_ctx.flags = flags;
+	pblk_ppa_set_empty(&w_ctx.ppa);
+
+	for (i = 0; i < nr_entries; i++) {
+		void *data = bio_data(bio);
+
+		w_ctx.lba = lba + i;
+
+		pos = pblk_rb_wrap_pos(&pblk->rwb, bpos + i);
+		pblk_rb_write_entry_user(&pblk->rwb, data, w_ctx, pos);
+
+		bio_advance(bio, PBLK_EXPOSED_PAGE_SIZE);
+	}
+
+#ifdef CONFIG_NVM_DEBUG
+	atomic_long_add(nr_entries, &pblk->inflight_writes);
+	atomic_long_add(nr_entries, &pblk->req_writes);
+#endif
+
+out:
+	pblk_write_should_kick(pblk);
+	return ret;
+}
+
+/*
+ * On GC the incoming lbas are not necessarily sequential. Also, some of the
+ * lbas might not be valid entries, which are marked as empty by the GC thread
+ */
+int pblk_write_gc_to_cache(struct pblk *pblk, void *data, u64 *lba_list,
+			   unsigned int nr_entries, unsigned int nr_rec_entries,
+			   struct pblk_line *gc_line, unsigned long flags)
+{
+	struct pblk_w_ctx w_ctx;
+	unsigned int bpos, pos;
+	int i, valid_entries;
+
+	/* Update the write buffer head (mem) with the entries that we can
+	 * write. The write in itself cannot fail, so there is no need to
+	 * rollback from here on.
+	 */
+retry:
+	if (!pblk_rb_may_write_gc(&pblk->rwb, nr_rec_entries, &bpos)) {
+		io_schedule();
+		goto retry;
+	}
+
+	w_ctx.flags = flags;
+	pblk_ppa_set_empty(&w_ctx.ppa);
+
+	for (i = 0, valid_entries = 0; i < nr_entries; i++) {
+		if (lba_list[i] == ADDR_EMPTY)
+			continue;
+
+		w_ctx.lba = lba_list[i];
+
+		pos = pblk_rb_wrap_pos(&pblk->rwb, bpos + valid_entries);
+		pblk_rb_write_entry_gc(&pblk->rwb, data, w_ctx, gc_line, pos);
+
+		data += PBLK_EXPOSED_PAGE_SIZE;
+		valid_entries++;
+	}
+
+	WARN_ONCE(nr_rec_entries != valid_entries,
+					"pblk: inconsistent GC write\n");
+
+#ifdef CONFIG_NVM_DEBUG
+	atomic_long_add(valid_entries, &pblk->inflight_writes);
+	atomic_long_add(valid_entries, &pblk->recov_gc_writes);
+#endif
+
+	pblk_write_should_kick(pblk);
+	return NVM_IO_OK;
+}

drivers/lightnvm/pblk-core.c

+/*
+ * Copyright (C) 2016 CNEX Labs
+ * Initial release: Javier Gonzalez <javier@cnexlabs.com>
+ *                  Matias Bjorling <matias@cnexlabs.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * pblk-core.c - pblk's core functionality
+ *
+ */
+
+#include "pblk.h"
+#include <linux/time.h>
+
+static void pblk_mark_bb(struct pblk *pblk, struct pblk_line *line,
+			 struct ppa_addr *ppa)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	int pos = pblk_dev_ppa_to_pos(geo, *ppa);
+
+	pr_debug("pblk: erase failed: line:%d, pos:%d\n", line->id, pos);
+	atomic_long_inc(&pblk->erase_failed);
+
+	if (test_and_set_bit(pos, line->blk_bitmap))
+		pr_err("pblk: attempted to erase bb: line:%d, pos:%d\n",
+							line->id, pos);
+
+	pblk_line_run_ws(pblk, NULL, ppa, pblk_line_mark_bb);
+}
+
+static void __pblk_end_io_erase(struct pblk *pblk, struct nvm_rq *rqd)
+{
+	struct pblk_line *line;
+
+	line = &pblk->lines[pblk_dev_ppa_to_line(rqd->ppa_addr)];
+	atomic_dec(&line->left_seblks);
+
+	if (rqd->error) {
+		struct ppa_addr *ppa;
+
+		ppa = kmalloc(sizeof(struct ppa_addr), GFP_ATOMIC);
+		if (!ppa)
+			return;
+
+		*ppa = rqd->ppa_addr;
+		pblk_mark_bb(pblk, line, ppa);
+	}
+}
+
+/* Erase completion assumes that only one block is erased at the time */
+static void pblk_end_io_erase(struct nvm_rq *rqd)
+{
+	struct pblk *pblk = rqd->private;
+
+	up(&pblk->erase_sem);
+	__pblk_end_io_erase(pblk, rqd);
+	mempool_free(rqd, pblk->r_rq_pool);
+}
+
+static void __pblk_map_invalidate(struct pblk *pblk, struct pblk_line *line,
+				  u64 paddr)
+{
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct list_head *move_list = NULL;
+
+	/* Lines being reclaimed (GC'ed) cannot be invalidated. Before the L2P
+	 * table is modified with reclaimed sectors, a check is done to endure
+	 * that newer updates are not overwritten.
+	 */
+	spin_lock(&line->lock);
+	if (line->state == PBLK_LINESTATE_GC ||
+					line->state == PBLK_LINESTATE_FREE) {
+		spin_unlock(&line->lock);
+		return;
+	}
+
+	if (test_and_set_bit(paddr, line->invalid_bitmap)) {
+		WARN_ONCE(1, "pblk: double invalidate\n");
+		spin_unlock(&line->lock);
+		return;
+	}
+	line->vsc--;
+
+	if (line->state == PBLK_LINESTATE_CLOSED)
+		move_list = pblk_line_gc_list(pblk, line);
+	spin_unlock(&line->lock);
+
+	if (move_list) {
+		spin_lock(&l_mg->gc_lock);
+		spin_lock(&line->lock);
+		/* Prevent moving a line that has just been chosen for GC */
+		if (line->state == PBLK_LINESTATE_GC ||
+					line->state == PBLK_LINESTATE_FREE) {
+			spin_unlock(&line->lock);
+			spin_unlock(&l_mg->gc_lock);
+			return;
+		}
+		spin_unlock(&line->lock);
+
+		list_move_tail(&line->list, move_list);
+		spin_unlock(&l_mg->gc_lock);
+	}
+}
+
+void pblk_map_invalidate(struct pblk *pblk, struct ppa_addr ppa)
+{
+	struct pblk_line *line;
+	u64 paddr;
+	int line_id;
+
+#ifdef CONFIG_NVM_DEBUG
+	/* Callers must ensure that the ppa points to a device address */
+	BUG_ON(pblk_addr_in_cache(ppa));
+	BUG_ON(pblk_ppa_empty(ppa));
+#endif
+
+	line_id = pblk_tgt_ppa_to_line(ppa);
+	line = &pblk->lines[line_id];
+	paddr = pblk_dev_ppa_to_line_addr(pblk, ppa);
+
+	__pblk_map_invalidate(pblk, line, paddr);
+}
+
+void pblk_map_pad_invalidate(struct pblk *pblk, struct pblk_line *line,
+			     u64 paddr)
+{
+	__pblk_map_invalidate(pblk, line, paddr);
+
+	pblk_rb_sync_init(&pblk->rwb, NULL);
+	line->left_ssecs--;
+	if (!line->left_ssecs)
+		pblk_line_run_ws(pblk, line, NULL, pblk_line_close_ws);
+	pblk_rb_sync_end(&pblk->rwb, NULL);
+}
+
+static void pblk_invalidate_range(struct pblk *pblk, sector_t slba,
+				  unsigned int nr_secs)
+{
+	sector_t lba;
+
+	spin_lock(&pblk->trans_lock);
+	for (lba = slba; lba < slba + nr_secs; lba++) {
+		struct ppa_addr ppa;
+
+		ppa = pblk_trans_map_get(pblk, lba);
+
+		if (!pblk_addr_in_cache(ppa) && !pblk_ppa_empty(ppa))
+			pblk_map_invalidate(pblk, ppa);
+
+		pblk_ppa_set_empty(&ppa);
+		pblk_trans_map_set(pblk, lba, ppa);
+	}
+	spin_unlock(&pblk->trans_lock);
+}
+
+struct nvm_rq *pblk_alloc_rqd(struct pblk *pblk, int rw)
+{
+	mempool_t *pool;
+	struct nvm_rq *rqd;
+	int rq_size;
+
+	if (rw == WRITE) {
+		pool = pblk->w_rq_pool;
+		rq_size = pblk_w_rq_size;
+	} else {
+		pool = pblk->r_rq_pool;
+		rq_size = pblk_r_rq_size;
+	}
+
+	rqd = mempool_alloc(pool, GFP_KERNEL);
+	memset(rqd, 0, rq_size);
+
+	return rqd;
+}
+
+void pblk_free_rqd(struct pblk *pblk, struct nvm_rq *rqd, int rw)
+{
+	mempool_t *pool;
+
+	if (rw == WRITE)
+		pool = pblk->w_rq_pool;
+	else
+		pool = pblk->r_rq_pool;
+
+	mempool_free(rqd, pool);
+}
+
+void pblk_bio_free_pages(struct pblk *pblk, struct bio *bio, int off,
+			 int nr_pages)
+{
+	struct bio_vec bv;
+	int i;
+
+	WARN_ON(off + nr_pages != bio->bi_vcnt);
+
+	bio_advance(bio, off * PBLK_EXPOSED_PAGE_SIZE);
+	for (i = off; i < nr_pages + off; i++) {
+		bv = bio->bi_io_vec[i];
+		mempool_free(bv.bv_page, pblk->page_pool);
+	}
+}
+
+int pblk_bio_add_pages(struct pblk *pblk, struct bio *bio, gfp_t flags,
+		       int nr_pages)
+{
+	struct request_queue *q = pblk->dev->q;
+	struct page *page;
+	int i, ret;
+
+	for (i = 0; i < nr_pages; i++) {
+		page = mempool_alloc(pblk->page_pool, flags);
+		if (!page)
+			goto err;
+
+		ret = bio_add_pc_page(q, bio, page, PBLK_EXPOSED_PAGE_SIZE, 0);
+		if (ret != PBLK_EXPOSED_PAGE_SIZE) {
+			pr_err("pblk: could not add page to bio\n");
+			mempool_free(page, pblk->page_pool);
+			goto err;
+		}
+	}
+
+	return 0;
+err:
+	pblk_bio_free_pages(pblk, bio, 0, i - 1);
+	return -1;
+}
+
+static void pblk_write_kick(struct pblk *pblk)
+{
+	wake_up_process(pblk->writer_ts);
+	mod_timer(&pblk->wtimer, jiffies + msecs_to_jiffies(1000));
+}
+
+void pblk_write_timer_fn(unsigned long data)
+{
+	struct pblk *pblk = (struct pblk *)data;
+
+	/* kick the write thread every tick to flush outstanding data */
+	pblk_write_kick(pblk);
+}
+
+void pblk_write_should_kick(struct pblk *pblk)
+{
+	unsigned int secs_avail = pblk_rb_read_count(&pblk->rwb);
+
+	if (secs_avail >= pblk->min_write_pgs)
+		pblk_write_kick(pblk);
+}
+
+void pblk_end_bio_sync(struct bio *bio)
+{
+	struct completion *waiting = bio->bi_private;
+
+	complete(waiting);
+}
+
+void pblk_end_io_sync(struct nvm_rq *rqd)
+{
+	struct completion *waiting = rqd->private;
+
+	complete(waiting);
+}
+
+void pblk_flush_writer(struct pblk *pblk)
+{
+	struct bio *bio;
+	int ret;
+	DECLARE_COMPLETION_ONSTACK(wait);
+
+	bio = bio_alloc(GFP_KERNEL, 1);
+	if (!bio)
+		return;
+
+	bio->bi_iter.bi_sector = 0; /* internal bio */
+	bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_OP_FLUSH);
+	bio->bi_private = &wait;
+	bio->bi_end_io = pblk_end_bio_sync;
+
+	ret = pblk_write_to_cache(pblk, bio, 0);
+	if (ret == NVM_IO_OK) {
+		if (!wait_for_completion_io_timeout(&wait,
+				msecs_to_jiffies(PBLK_COMMAND_TIMEOUT_MS))) {
+			pr_err("pblk: flush cache timed out\n");
+		}
+	} else if (ret != NVM_IO_DONE) {
+		pr_err("pblk: tear down bio failed\n");
+	}
+
+	if (bio->bi_error)
+		pr_err("pblk: flush sync write failed (%u)\n", bio->bi_error);
+
+	bio_put(bio);
+}
+
+struct list_head *pblk_line_gc_list(struct pblk *pblk, struct pblk_line *line)
+{
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct list_head *move_list = NULL;
+
+	if (!line->vsc) {
+		if (line->gc_group != PBLK_LINEGC_FULL) {
+			line->gc_group = PBLK_LINEGC_FULL;
+			move_list = &l_mg->gc_full_list;
+		}
+	} else if (line->vsc < lm->mid_thrs) {
+		if (line->gc_group != PBLK_LINEGC_HIGH) {
+			line->gc_group = PBLK_LINEGC_HIGH;
+			move_list = &l_mg->gc_high_list;
+		}
+	} else if (line->vsc < lm->high_thrs) {
+		if (line->gc_group != PBLK_LINEGC_MID) {
+			line->gc_group = PBLK_LINEGC_MID;
+			move_list = &l_mg->gc_mid_list;
+		}
+	} else if (line->vsc < line->sec_in_line) {
+		if (line->gc_group != PBLK_LINEGC_LOW) {
+			line->gc_group = PBLK_LINEGC_LOW;
+			move_list = &l_mg->gc_low_list;
+		}
+	} else if (line->vsc == line->sec_in_line) {
+		if (line->gc_group != PBLK_LINEGC_EMPTY) {
+			line->gc_group = PBLK_LINEGC_EMPTY;
+			move_list = &l_mg->gc_empty_list;
+		}
+	} else {
+		line->state = PBLK_LINESTATE_CORRUPT;
+		line->gc_group = PBLK_LINEGC_NONE;
+		move_list =  &l_mg->corrupt_list;
+		pr_err("pblk: corrupted vsc for line %d, vsc:%d (%d/%d/%d)\n",
+						line->id, line->vsc,
+						line->sec_in_line,
+						lm->high_thrs, lm->mid_thrs);
+	}
+
+	return move_list;
+}
+
+void pblk_discard(struct pblk *pblk, struct bio *bio)
+{
+	sector_t slba = pblk_get_lba(bio);
+	sector_t nr_secs = pblk_get_secs(bio);
+
+	pblk_invalidate_range(pblk, slba, nr_secs);
+}
+
+struct ppa_addr pblk_get_lba_map(struct pblk *pblk, sector_t lba)
+{
+	struct ppa_addr ppa;
+
+	spin_lock(&pblk->trans_lock);
+	ppa = pblk_trans_map_get(pblk, lba);
+	spin_unlock(&pblk->trans_lock);
+
+	return ppa;
+}
+
+void pblk_log_write_err(struct pblk *pblk, struct nvm_rq *rqd)
+{
+	atomic_long_inc(&pblk->write_failed);
+#ifdef CONFIG_NVM_DEBUG
+	pblk_print_failed_rqd(pblk, rqd, rqd->error);
+#endif
+}
+
+void pblk_log_read_err(struct pblk *pblk, struct nvm_rq *rqd)
+{
+	/* Empty page read is not necessarily an error (e.g., L2P recovery) */
+	if (rqd->error == NVM_RSP_ERR_EMPTYPAGE) {
+		atomic_long_inc(&pblk->read_empty);
+		return;
+	}
+
+	switch (rqd->error) {
+	case NVM_RSP_WARN_HIGHECC:
+		atomic_long_inc(&pblk->read_high_ecc);
+		break;
+	case NVM_RSP_ERR_FAILECC:
+	case NVM_RSP_ERR_FAILCRC:
+		atomic_long_inc(&pblk->read_failed);
+		break;
+	default:
+		pr_err("pblk: unknown read error:%d\n", rqd->error);
+	}
+#ifdef CONFIG_NVM_DEBUG
+	pblk_print_failed_rqd(pblk, rqd, rqd->error);
+#endif
+}
+
+int pblk_submit_io(struct pblk *pblk, struct nvm_rq *rqd)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+
+#ifdef CONFIG_NVM_DEBUG
+	struct ppa_addr *ppa_list;
+
+	ppa_list = (rqd->nr_ppas > 1) ? rqd->ppa_list : &rqd->ppa_addr;
+	if (pblk_boundary_ppa_checks(dev, ppa_list, rqd->nr_ppas)) {
+		WARN_ON(1);
+		return -EINVAL;
+	}
+
+	if (rqd->opcode == NVM_OP_PWRITE) {
+		struct pblk_line *line;
+		struct ppa_addr ppa;
+		int i;
+
+		for (i = 0; i < rqd->nr_ppas; i++) {
+			ppa = ppa_list[i];
+			line = &pblk->lines[pblk_dev_ppa_to_line(ppa)];
+
+			spin_lock(&line->lock);
+			if (line->state != PBLK_LINESTATE_OPEN) {
+				pr_err("pblk: bad ppa: line:%d,state:%d\n",
+							line->id, line->state);
+				WARN_ON(1);
+				spin_unlock(&line->lock);
+				return -EINVAL;
+			}
+			spin_unlock(&line->lock);
+		}
+	}
+#endif
+	return nvm_submit_io(dev, rqd);
+}
+
+struct bio *pblk_bio_map_addr(struct pblk *pblk, void *data,
+			      unsigned int nr_secs, unsigned int len,
+			      gfp_t gfp_mask)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	void *kaddr = data;
+	struct page *page;
+	struct bio *bio;
+	int i, ret;
+
+	if (l_mg->emeta_alloc_type == PBLK_KMALLOC_META)
+		return bio_map_kern(dev->q, kaddr, len, gfp_mask);
+
+	bio = bio_kmalloc(gfp_mask, nr_secs);
+	if (!bio)
+		return ERR_PTR(-ENOMEM);
+
+	for (i = 0; i < nr_secs; i++) {
+		page = vmalloc_to_page(kaddr);
+		if (!page) {
+			pr_err("pblk: could not map vmalloc bio\n");
+			bio_put(bio);
+			bio = ERR_PTR(-ENOMEM);
+			goto out;
+		}
+
+		ret = bio_add_pc_page(dev->q, bio, page, PAGE_SIZE, 0);
+		if (ret != PAGE_SIZE) {
+			pr_err("pblk: could not add page to bio\n");
+			bio_put(bio);
+			bio = ERR_PTR(-ENOMEM);
+			goto out;
+		}
+
+		kaddr += PAGE_SIZE;
+	}
+out:
+	return bio;
+}
+
+int pblk_calc_secs(struct pblk *pblk, unsigned long secs_avail,
+		   unsigned long secs_to_flush)
+{
+	int max = pblk->max_write_pgs;
+	int min = pblk->min_write_pgs;
+	int secs_to_sync = 0;
+
+	if (secs_avail >= max)
+		secs_to_sync = max;
+	else if (secs_avail >= min)
+		secs_to_sync = min * (secs_avail / min);
+	else if (secs_to_flush)
+		secs_to_sync = min;
+
+	return secs_to_sync;
+}
+
+static u64 __pblk_alloc_page(struct pblk *pblk, struct pblk_line *line,
+			     int nr_secs)
+{
+	u64 addr;
+	int i;
+
+	/* logic error: ppa out-of-bounds. Prevent generating bad address */
+	if (line->cur_sec + nr_secs > pblk->lm.sec_per_line) {
+		WARN(1, "pblk: page allocation out of bounds\n");
+		nr_secs = pblk->lm.sec_per_line - line->cur_sec;
+	}
+
+	line->cur_sec = addr = find_next_zero_bit(line->map_bitmap,
+					pblk->lm.sec_per_line, line->cur_sec);
+	for (i = 0; i < nr_secs; i++, line->cur_sec++)
+		WARN_ON(test_and_set_bit(line->cur_sec, line->map_bitmap));
+
+	return addr;
+}
+
+u64 pblk_alloc_page(struct pblk *pblk, struct pblk_line *line, int nr_secs)
+{
+	u64 addr;
+
+	/* Lock needed in case a write fails and a recovery needs to remap
+	 * failed write buffer entries
+	 */
+	spin_lock(&line->lock);
+	addr = __pblk_alloc_page(pblk, line, nr_secs);
+	line->left_msecs -= nr_secs;
+	WARN(line->left_msecs < 0, "pblk: page allocation out of bounds\n");
+	spin_unlock(&line->lock);
+
+	return addr;
+}
+
+/*
+ * Submit emeta to one LUN in the raid line at the time to avoid a deadlock when
+ * taking the per LUN semaphore.
+ */
+static int pblk_line_submit_emeta_io(struct pblk *pblk, struct pblk_line *line,
+				     u64 paddr, int dir)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct bio *bio;
+	struct nvm_rq rqd;
+	struct ppa_addr *ppa_list;
+	dma_addr_t dma_ppa_list;
+	void *emeta = line->emeta;
+	int min = pblk->min_write_pgs;
+	int left_ppas = lm->emeta_sec;
+	int id = line->id;
+	int rq_ppas, rq_len;
+	int cmd_op, bio_op;
+	int flags;
+	int i, j;
+	int ret;
+	DECLARE_COMPLETION_ONSTACK(wait);
+
+	if (dir == WRITE) {
+		bio_op = REQ_OP_WRITE;
+		cmd_op = NVM_OP_PWRITE;
+		flags = pblk_set_progr_mode(pblk, WRITE);
+	} else if (dir == READ) {
+		bio_op = REQ_OP_READ;
+		cmd_op = NVM_OP_PREAD;
+		flags = pblk_set_read_mode(pblk);
+	} else
+		return -EINVAL;
+
+	ppa_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL, &dma_ppa_list);
+	if (!ppa_list)
+		return -ENOMEM;
+
+next_rq:
+	memset(&rqd, 0, sizeof(struct nvm_rq));
+
+	rq_ppas = pblk_calc_secs(pblk, left_ppas, 0);
+	rq_len = rq_ppas * geo->sec_size;
+
+	bio = pblk_bio_map_addr(pblk, emeta, rq_ppas, rq_len, GFP_KERNEL);
+	if (IS_ERR(bio)) {
+		ret = PTR_ERR(bio);
+		goto free_rqd_dma;
+	}
+
+	bio->bi_iter.bi_sector = 0; /* internal bio */
+	bio_set_op_attrs(bio, bio_op, 0);
+
+	rqd.bio = bio;
+	rqd.opcode = cmd_op;
+	rqd.flags = flags;
+	rqd.nr_ppas = rq_ppas;
+	rqd.ppa_list = ppa_list;
+	rqd.dma_ppa_list = dma_ppa_list;
+	rqd.end_io = pblk_end_io_sync;
+	rqd.private = &wait;
+
+	if (dir == WRITE) {
+		for (i = 0; i < rqd.nr_ppas; ) {
+			spin_lock(&line->lock);
+			paddr = __pblk_alloc_page(pblk, line, min);
+			spin_unlock(&line->lock);
+			for (j = 0; j < min; j++, i++, paddr++)
+				rqd.ppa_list[i] =
+					addr_to_gen_ppa(pblk, paddr, id);
+		}
+	} else {
+		for (i = 0; i < rqd.nr_ppas; ) {
+			struct ppa_addr ppa = addr_to_gen_ppa(pblk, paddr, id);
+			int pos = pblk_dev_ppa_to_pos(geo, ppa);
+
+			while (test_bit(pos, line->blk_bitmap)) {
+				paddr += min;
+				if (pblk_boundary_paddr_checks(pblk, paddr)) {
+					pr_err("pblk: corrupt emeta line:%d\n",
+								line->id);
+					bio_put(bio);
+					ret = -EINTR;
+					goto free_rqd_dma;
+				}
+
+				ppa = addr_to_gen_ppa(pblk, paddr, id);
+				pos = pblk_dev_ppa_to_pos(geo, ppa);
+			}
+
+			if (pblk_boundary_paddr_checks(pblk, paddr + min)) {
+				pr_err("pblk: corrupt emeta line:%d\n",
+								line->id);
+				bio_put(bio);
+				ret = -EINTR;
+				goto free_rqd_dma;
+			}
+
+			for (j = 0; j < min; j++, i++, paddr++)
+				rqd.ppa_list[i] =
+					addr_to_gen_ppa(pblk, paddr, line->id);
+		}
+	}
+
+	ret = pblk_submit_io(pblk, &rqd);
+	if (ret) {
+		pr_err("pblk: emeta I/O submission failed: %d\n", ret);
+		bio_put(bio);
+		goto free_rqd_dma;
+	}
+
+	if (!wait_for_completion_io_timeout(&wait,
+				msecs_to_jiffies(PBLK_COMMAND_TIMEOUT_MS))) {
+		pr_err("pblk: emeta I/O timed out\n");
+	}
+	reinit_completion(&wait);
+
+	bio_put(bio);
+
+	if (rqd.error) {
+		if (dir == WRITE)
+			pblk_log_write_err(pblk, &rqd);
+		else
+			pblk_log_read_err(pblk, &rqd);
+	}
+
+	emeta += rq_len;
+	left_ppas -= rq_ppas;
+	if (left_ppas)
+		goto next_rq;
+free_rqd_dma:
+	nvm_dev_dma_free(dev->parent, ppa_list, dma_ppa_list);
+	return ret;
+}
+
+u64 pblk_line_smeta_start(struct pblk *pblk, struct pblk_line *line)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_line_meta *lm = &pblk->lm;
+	int bit;
+
+	/* This usually only happens on bad lines */
+	bit = find_first_zero_bit(line->blk_bitmap, lm->blk_per_line);
+	if (bit >= lm->blk_per_line)
+		return -1;
+
+	return bit * geo->sec_per_pl;
+}
+
+static int pblk_line_submit_smeta_io(struct pblk *pblk, struct pblk_line *line,
+				     u64 paddr, int dir)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct bio *bio;
+	struct nvm_rq rqd;
+	__le64 *lba_list = NULL;
+	int i, ret;
+	int cmd_op, bio_op;
+	int flags;
+	DECLARE_COMPLETION_ONSTACK(wait);
+
+	if (dir == WRITE) {
+		bio_op = REQ_OP_WRITE;
+		cmd_op = NVM_OP_PWRITE;
+		flags = pblk_set_progr_mode(pblk, WRITE);
+		lba_list = pblk_line_emeta_to_lbas(line->emeta);
+	} else if (dir == READ) {
+		bio_op = REQ_OP_READ;
+		cmd_op = NVM_OP_PREAD;
+		flags = pblk_set_read_mode(pblk);
+	} else
+		return -EINVAL;
+
+	memset(&rqd, 0, sizeof(struct nvm_rq));
+
+	rqd.ppa_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
+							&rqd.dma_ppa_list);
+	if (!rqd.ppa_list)
+		return -ENOMEM;
+
+	bio = bio_map_kern(dev->q, line->smeta, lm->smeta_len, GFP_KERNEL);
+	if (IS_ERR(bio)) {
+		ret = PTR_ERR(bio);
+		goto free_ppa_list;
+	}
+
+	bio->bi_iter.bi_sector = 0; /* internal bio */
+	bio_set_op_attrs(bio, bio_op, 0);
+
+	rqd.bio = bio;
+	rqd.opcode = cmd_op;
+	rqd.flags = flags;
+	rqd.nr_ppas = lm->smeta_sec;
+	rqd.end_io = pblk_end_io_sync;
+	rqd.private = &wait;
+
+	for (i = 0; i < lm->smeta_sec; i++, paddr++) {
+		rqd.ppa_list[i] = addr_to_gen_ppa(pblk, paddr, line->id);
+		if (dir == WRITE)
+			lba_list[paddr] = cpu_to_le64(ADDR_EMPTY);
+	}
+
+	/*
+	 * This I/O is sent by the write thread when a line is replace. Since
+	 * the write thread is the only one sending write and erase commands,
+	 * there is no need to take the LUN semaphore.
+	 */
+	ret = pblk_submit_io(pblk, &rqd);
+	if (ret) {
+		pr_err("pblk: smeta I/O submission failed: %d\n", ret);
+		bio_put(bio);
+		goto free_ppa_list;
+	}
+
+	if (!wait_for_completion_io_timeout(&wait,
+				msecs_to_jiffies(PBLK_COMMAND_TIMEOUT_MS))) {
+		pr_err("pblk: smeta I/O timed out\n");
+	}
+
+	if (rqd.error) {
+		if (dir == WRITE)
+			pblk_log_write_err(pblk, &rqd);
+		else
+			pblk_log_read_err(pblk, &rqd);
+	}
+
+free_ppa_list:
+	nvm_dev_dma_free(dev->parent, rqd.ppa_list, rqd.dma_ppa_list);
+
+	return ret;
+}
+
+int pblk_line_read_smeta(struct pblk *pblk, struct pblk_line *line)
+{
+	u64 bpaddr = pblk_line_smeta_start(pblk, line);
+
+	return pblk_line_submit_smeta_io(pblk, line, bpaddr, READ);
+}
+
+int pblk_line_read_emeta(struct pblk *pblk, struct pblk_line *line)
+{
+	return pblk_line_submit_emeta_io(pblk, line, line->emeta_ssec, READ);
+}
+
+static void pblk_setup_e_rq(struct pblk *pblk, struct nvm_rq *rqd,
+			    struct ppa_addr ppa)
+{
+	rqd->opcode = NVM_OP_ERASE;
+	rqd->ppa_addr = ppa;
+	rqd->nr_ppas = 1;
+	rqd->flags = pblk_set_progr_mode(pblk, ERASE);
+	rqd->bio = NULL;
+}
+
+static int pblk_blk_erase_sync(struct pblk *pblk, struct ppa_addr ppa)
+{
+	struct nvm_rq rqd;
+	int ret;
+	DECLARE_COMPLETION_ONSTACK(wait);
+
+	memset(&rqd, 0, sizeof(struct nvm_rq));
+
+	pblk_setup_e_rq(pblk, &rqd, ppa);
+
+	rqd.end_io = pblk_end_io_sync;
+	rqd.private = &wait;
+
+	/* The write thread schedules erases so that it minimizes disturbances
+	 * with writes. Thus, there is no need to take the LUN semaphore.
+	 */
+	ret = pblk_submit_io(pblk, &rqd);
+	if (ret) {
+		struct nvm_tgt_dev *dev = pblk->dev;
+		struct nvm_geo *geo = &dev->geo;
+
+		pr_err("pblk: could not sync erase line:%d,blk:%d\n",
+					pblk_dev_ppa_to_line(ppa),
+					pblk_dev_ppa_to_pos(geo, ppa));
+
+		rqd.error = ret;
+		goto out;
+	}
+
+	if (!wait_for_completion_io_timeout(&wait,
+				msecs_to_jiffies(PBLK_COMMAND_TIMEOUT_MS))) {
+		pr_err("pblk: sync erase timed out\n");
+	}
+
+out:
+	rqd.private = pblk;
+	__pblk_end_io_erase(pblk, &rqd);
+
+	return 0;
+}
+
+int pblk_line_erase(struct pblk *pblk, struct pblk_line *line)
+{
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct ppa_addr ppa;
+	int bit = -1;
+
+	/* Erase one block at the time and only erase good blocks */
+	while ((bit = find_next_zero_bit(line->erase_bitmap, lm->blk_per_line,
+						bit + 1)) < lm->blk_per_line) {
+		ppa = pblk->luns[bit].bppa; /* set ch and lun */
+		ppa.g.blk = line->id;
+
+		/* If the erase fails, the block is bad and should be marked */
+		line->left_eblks--;
+		WARN_ON(test_and_set_bit(bit, line->erase_bitmap));
+
+		if (pblk_blk_erase_sync(pblk, ppa)) {
+			pr_err("pblk: failed to erase line %d\n", line->id);
+			return -ENOMEM;
+		}
+	}
+
+	return 0;
+}
+
+/* For now lines are always assumed full lines. Thus, smeta former and current
+ * lun bitmaps are omitted.
+ */
+static int pblk_line_set_metadata(struct pblk *pblk, struct pblk_line *line,
+				  struct pblk_line *cur)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct line_smeta *smeta = line->smeta;
+	struct line_emeta *emeta = line->emeta;
+	int nr_blk_line;
+
+	/* After erasing the line, new bad blocks might appear and we risk
+	 * having an invalid line
+	 */
+	nr_blk_line = lm->blk_per_line -
+			bitmap_weight(line->blk_bitmap, lm->blk_per_line);
+	if (nr_blk_line < lm->min_blk_line) {
+		spin_lock(&l_mg->free_lock);
+		spin_lock(&line->lock);
+		line->state = PBLK_LINESTATE_BAD;
+		spin_unlock(&line->lock);
+
+		list_add_tail(&line->list, &l_mg->bad_list);
+		spin_unlock(&l_mg->free_lock);
+
+		pr_debug("pblk: line %d is bad\n", line->id);
+
+		return 0;
+	}
+
+	/* Run-time metadata */
+	line->lun_bitmap = ((void *)(smeta)) + sizeof(struct line_smeta);
+
+	/* Mark LUNs allocated in this line (all for now) */
+	bitmap_set(line->lun_bitmap, 0, lm->lun_bitmap_len);
+
+	smeta->header.identifier = cpu_to_le32(PBLK_MAGIC);
+	memcpy(smeta->header.uuid, pblk->instance_uuid, 16);
+	smeta->header.id = cpu_to_le32(line->id);
+	smeta->header.type = cpu_to_le16(line->type);
+	smeta->header.version = cpu_to_le16(1);
+
+	/* Start metadata */
+	smeta->seq_nr = cpu_to_le64(line->seq_nr);
+	smeta->window_wr_lun = cpu_to_le32(geo->nr_luns);
+
+	/* Fill metadata among lines */
+	if (cur) {
+		memcpy(line->lun_bitmap, cur->lun_bitmap, lm->lun_bitmap_len);
+		smeta->prev_id = cpu_to_le32(cur->id);
+		cur->emeta->next_id = cpu_to_le32(line->id);
+	} else {
+		smeta->prev_id = cpu_to_le32(PBLK_LINE_EMPTY);
+	}
+
+	/* All smeta must be set at this point */
+	smeta->header.crc = cpu_to_le32(pblk_calc_meta_header_crc(pblk, smeta));
+	smeta->crc = cpu_to_le32(pblk_calc_smeta_crc(pblk, smeta));
+
+	/* End metadata */
+	memcpy(&emeta->header, &smeta->header, sizeof(struct line_header));
+	emeta->seq_nr = cpu_to_le64(line->seq_nr);
+	emeta->nr_lbas = cpu_to_le64(line->sec_in_line);
+	emeta->nr_valid_lbas = cpu_to_le64(0);
+	emeta->next_id = cpu_to_le32(PBLK_LINE_EMPTY);
+	emeta->crc = cpu_to_le32(0);
+	emeta->prev_id = smeta->prev_id;
+
+	return 1;
+}
+
+/* For now lines are always assumed full lines. Thus, smeta former and current
+ * lun bitmaps are omitted.
+ */
+static int pblk_line_init_bb(struct pblk *pblk, struct pblk_line *line,
+			     int init)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	int nr_bb = 0;
+	u64 off;
+	int bit = -1;
+
+	line->sec_in_line = lm->sec_per_line;
+
+	/* Capture bad block information on line mapping bitmaps */
+	while ((bit = find_next_bit(line->blk_bitmap, lm->blk_per_line,
+					bit + 1)) < lm->blk_per_line) {
+		off = bit * geo->sec_per_pl;
+		bitmap_shift_left(l_mg->bb_aux, l_mg->bb_template, off,
+							lm->sec_per_line);
+		bitmap_or(line->map_bitmap, line->map_bitmap, l_mg->bb_aux,
+							lm->sec_per_line);
+		line->sec_in_line -= geo->sec_per_blk;
+		if (bit >= lm->emeta_bb)
+			nr_bb++;
+	}
+
+	/* Mark smeta metadata sectors as bad sectors */
+	bit = find_first_zero_bit(line->blk_bitmap, lm->blk_per_line);
+	off = bit * geo->sec_per_pl;
+retry_smeta:
+	bitmap_set(line->map_bitmap, off, lm->smeta_sec);
+	line->sec_in_line -= lm->smeta_sec;
+	line->smeta_ssec = off;
+	line->cur_sec = off + lm->smeta_sec;
+
+	if (init && pblk_line_submit_smeta_io(pblk, line, off, WRITE)) {
+		pr_debug("pblk: line smeta I/O failed. Retry\n");
+		off += geo->sec_per_pl;
+		goto retry_smeta;
+	}
+
+	bitmap_copy(line->invalid_bitmap, line->map_bitmap, lm->sec_per_line);
+
+	/* Mark emeta metadata sectors as bad sectors. We need to consider bad
+	 * blocks to make sure that there are enough sectors to store emeta
+	 */
+	bit = lm->sec_per_line;
+	off = lm->sec_per_line - lm->emeta_sec;
+	bitmap_set(line->invalid_bitmap, off, lm->emeta_sec);
+	while (nr_bb) {
+		off -= geo->sec_per_pl;
+		if (!test_bit(off, line->invalid_bitmap)) {
+			bitmap_set(line->invalid_bitmap, off, geo->sec_per_pl);
+			nr_bb--;
+		}
+	}
+
+	line->sec_in_line -= lm->emeta_sec;
+	line->emeta_ssec = off;
+	line->vsc = line->left_ssecs = line->left_msecs = line->sec_in_line;
+
+	if (lm->sec_per_line - line->sec_in_line !=
+		bitmap_weight(line->invalid_bitmap, lm->sec_per_line)) {
+		spin_lock(&line->lock);
+		line->state = PBLK_LINESTATE_BAD;
+		spin_unlock(&line->lock);
+
+		list_add_tail(&line->list, &l_mg->bad_list);
+		pr_err("pblk: unexpected line %d is bad\n", line->id);
+
+		return 0;
+	}
+
+	return 1;
+}
+
+static int pblk_line_prepare(struct pblk *pblk, struct pblk_line *line)
+{
+	struct pblk_line_meta *lm = &pblk->lm;
+
+	line->map_bitmap = mempool_alloc(pblk->line_meta_pool, GFP_ATOMIC);
+	if (!line->map_bitmap)
+		return -ENOMEM;
+	memset(line->map_bitmap, 0, lm->sec_bitmap_len);
+
+	/* invalid_bitmap is special since it is used when line is closed. No
+	 * need to zeroized; it will be initialized using bb info form
+	 * map_bitmap
+	 */
+	line->invalid_bitmap = mempool_alloc(pblk->line_meta_pool, GFP_ATOMIC);
+	if (!line->invalid_bitmap) {
+		mempool_free(line->map_bitmap, pblk->line_meta_pool);
+		return -ENOMEM;
+	}
+
+	spin_lock(&line->lock);
+	if (line->state != PBLK_LINESTATE_FREE) {
+		spin_unlock(&line->lock);
+		WARN(1, "pblk: corrupted line state\n");
+		return -EINTR;
+	}
+	line->state = PBLK_LINESTATE_OPEN;
+	spin_unlock(&line->lock);
+
+	/* Bad blocks do not need to be erased */
+	bitmap_copy(line->erase_bitmap, line->blk_bitmap, lm->blk_per_line);
+	line->left_eblks = line->blk_in_line;
+	atomic_set(&line->left_seblks, line->left_eblks);
+
+	kref_init(&line->ref);
+
+	return 0;
+}
+
+int pblk_line_recov_alloc(struct pblk *pblk, struct pblk_line *line)
+{
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	int ret;
+
+	spin_lock(&l_mg->free_lock);
+	l_mg->data_line = line;
+	list_del(&line->list);
+	spin_unlock(&l_mg->free_lock);
+
+	ret = pblk_line_prepare(pblk, line);
+	if (ret) {
+		list_add(&line->list, &l_mg->free_list);
+		return ret;
+	}
+
+	pblk_rl_free_lines_dec(&pblk->rl, line);
+
+	if (!pblk_line_init_bb(pblk, line, 0)) {
+		list_add(&line->list, &l_mg->free_list);
+		return -EINTR;
+	}
+
+	return 0;
+}
+
+void pblk_line_recov_close(struct pblk *pblk, struct pblk_line *line)
+{
+	mempool_free(line->map_bitmap, pblk->line_meta_pool);
+	line->map_bitmap = NULL;
+	line->smeta = NULL;
+	line->emeta = NULL;
+}
+
+struct pblk_line *pblk_line_get(struct pblk *pblk)
+{
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct pblk_line *line = NULL;
+	int bit;
+
+	lockdep_assert_held(&l_mg->free_lock);
+
+retry_get:
+	if (list_empty(&l_mg->free_list)) {
+		pr_err("pblk: no free lines\n");
+		goto out;
+	}
+
+	line = list_first_entry(&l_mg->free_list, struct pblk_line, list);
+	list_del(&line->list);
+	l_mg->nr_free_lines--;
+
+	bit = find_first_zero_bit(line->blk_bitmap, lm->blk_per_line);
+	if (unlikely(bit >= lm->blk_per_line)) {
+		spin_lock(&line->lock);
+		line->state = PBLK_LINESTATE_BAD;
+		spin_unlock(&line->lock);
+
+		list_add_tail(&line->list, &l_mg->bad_list);
+
+		pr_debug("pblk: line %d is bad\n", line->id);
+		goto retry_get;
+	}
+
+	if (pblk_line_prepare(pblk, line)) {
+		pr_err("pblk: failed to prepare line %d\n", line->id);
+		list_add(&line->list, &l_mg->free_list);
+		return NULL;
+	}
+
+out:
+	return line;
+}
+
+static struct pblk_line *pblk_line_retry(struct pblk *pblk,
+					 struct pblk_line *line)
+{
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct pblk_line *retry_line;
+
+	spin_lock(&l_mg->free_lock);
+	retry_line = pblk_line_get(pblk);
+	if (!retry_line) {
+		spin_unlock(&l_mg->free_lock);
+		return NULL;
+	}
+
+	retry_line->smeta = line->smeta;
+	retry_line->emeta = line->emeta;
+	retry_line->meta_line = line->meta_line;
+	retry_line->map_bitmap = line->map_bitmap;
+	retry_line->invalid_bitmap = line->invalid_bitmap;
+
+	line->map_bitmap = NULL;
+	line->invalid_bitmap = NULL;
+	line->smeta = NULL;
+	line->emeta = NULL;
+	spin_unlock(&l_mg->free_lock);
+
+	if (pblk_line_erase(pblk, retry_line))
+		return NULL;
+
+	pblk_rl_free_lines_dec(&pblk->rl, retry_line);
+
+	l_mg->data_line = retry_line;
+
+	return retry_line;
+}
+
+struct pblk_line *pblk_line_get_first_data(struct pblk *pblk)
+{
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct pblk_line *line;
+	int meta_line;
+	int is_next = 0;
+
+	spin_lock(&l_mg->free_lock);
+	line = pblk_line_get(pblk);
+	if (!line) {
+		spin_unlock(&l_mg->free_lock);
+		return NULL;
+	}
+
+	line->seq_nr = l_mg->d_seq_nr++;
+	line->type = PBLK_LINETYPE_DATA;
+	l_mg->data_line = line;
+
+	meta_line = find_first_zero_bit(&l_mg->meta_bitmap, PBLK_DATA_LINES);
+	set_bit(meta_line, &l_mg->meta_bitmap);
+	line->smeta = l_mg->sline_meta[meta_line].meta;
+	line->emeta = l_mg->eline_meta[meta_line].meta;
+	line->meta_line = meta_line;
+
+	/* Allocate next line for preparation */
+	l_mg->data_next = pblk_line_get(pblk);
+	if (l_mg->data_next) {
+		l_mg->data_next->seq_nr = l_mg->d_seq_nr++;
+		l_mg->data_next->type = PBLK_LINETYPE_DATA;
+		is_next = 1;
+	}
+	spin_unlock(&l_mg->free_lock);
+
+	pblk_rl_free_lines_dec(&pblk->rl, line);
+	if (is_next)
+		pblk_rl_free_lines_dec(&pblk->rl, l_mg->data_next);
+
+	if (pblk_line_erase(pblk, line))
+		return NULL;
+
+retry_setup:
+	if (!pblk_line_set_metadata(pblk, line, NULL)) {
+		line = pblk_line_retry(pblk, line);
+		if (!line)
+			return NULL;
+
+		goto retry_setup;
+	}
+
+	if (!pblk_line_init_bb(pblk, line, 1)) {
+		line = pblk_line_retry(pblk, line);
+		if (!line)
+			return NULL;
+
+		goto retry_setup;
+	}
+
+	return line;
+}
+
+struct pblk_line *pblk_line_replace_data(struct pblk *pblk)
+{
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct pblk_line *cur, *new;
+	unsigned int left_seblks;
+	int meta_line;
+	int is_next = 0;
+
+	cur = l_mg->data_line;
+	new = l_mg->data_next;
+	if (!new)
+		return NULL;
+	l_mg->data_line = new;
+
+retry_line:
+	left_seblks = atomic_read(&new->left_seblks);
+	if (left_seblks) {
+		/* If line is not fully erased, erase it */
+		if (new->left_eblks) {
+			if (pblk_line_erase(pblk, new))
+				return NULL;
+		} else {
+			io_schedule();
+		}
+		goto retry_line;
+	}
+
+	spin_lock(&l_mg->free_lock);
+	/* Allocate next line for preparation */
+	l_mg->data_next = pblk_line_get(pblk);
+	if (l_mg->data_next) {
+		l_mg->data_next->seq_nr = l_mg->d_seq_nr++;
+		l_mg->data_next->type = PBLK_LINETYPE_DATA;
+		is_next = 1;
+	}
+
+retry_meta:
+	meta_line = find_first_zero_bit(&l_mg->meta_bitmap, PBLK_DATA_LINES);
+	if (meta_line == PBLK_DATA_LINES) {
+		spin_unlock(&l_mg->free_lock);
+		io_schedule();
+		spin_lock(&l_mg->free_lock);
+		goto retry_meta;
+	}
+
+	set_bit(meta_line, &l_mg->meta_bitmap);
+	new->smeta = l_mg->sline_meta[meta_line].meta;
+	new->emeta = l_mg->eline_meta[meta_line].meta;
+	new->meta_line = meta_line;
+
+	memset(new->smeta, 0, lm->smeta_len);
+	memset(new->emeta, 0, lm->emeta_len);
+	spin_unlock(&l_mg->free_lock);
+
+	if (is_next)
+		pblk_rl_free_lines_dec(&pblk->rl, l_mg->data_next);
+
+retry_setup:
+	if (!pblk_line_set_metadata(pblk, new, cur)) {
+		new = pblk_line_retry(pblk, new);
+		if (new)
+			return NULL;
+
+		goto retry_setup;
+	}
+
+	if (!pblk_line_init_bb(pblk, new, 1)) {
+		new = pblk_line_retry(pblk, new);
+		if (!new)
+			return NULL;
+
+		goto retry_setup;
+	}
+
+	return new;
+}
+
+void pblk_line_free(struct pblk *pblk, struct pblk_line *line)
+{
+	if (line->map_bitmap)
+		mempool_free(line->map_bitmap, pblk->line_meta_pool);
+	if (line->invalid_bitmap)
+		mempool_free(line->invalid_bitmap, pblk->line_meta_pool);
+
+	line->map_bitmap = NULL;
+	line->invalid_bitmap = NULL;
+}
+
+void pblk_line_put(struct kref *ref)
+{
+	struct pblk_line *line = container_of(ref, struct pblk_line, ref);
+	struct pblk *pblk = line->pblk;
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+
+	spin_lock(&line->lock);
+	WARN_ON(line->state != PBLK_LINESTATE_GC);
+	line->state = PBLK_LINESTATE_FREE;
+	line->gc_group = PBLK_LINEGC_NONE;
+	pblk_line_free(pblk, line);
+	spin_unlock(&line->lock);
+
+	spin_lock(&l_mg->free_lock);
+	list_add_tail(&line->list, &l_mg->free_list);
+	l_mg->nr_free_lines++;
+	spin_unlock(&l_mg->free_lock);
+
+	pblk_rl_free_lines_inc(&pblk->rl, line);
+}
+
+int pblk_blk_erase_async(struct pblk *pblk, struct ppa_addr ppa)
+{
+	struct nvm_rq *rqd;
+	int err;
+
+	rqd = mempool_alloc(pblk->r_rq_pool, GFP_KERNEL);
+	memset(rqd, 0, pblk_r_rq_size);
+
+	pblk_setup_e_rq(pblk, rqd, ppa);
+
+	rqd->end_io = pblk_end_io_erase;
+	rqd->private = pblk;
+
+	/* The write thread schedules erases so that it minimizes disturbances
+	 * with writes. Thus, there is no need to take the LUN semaphore.
+	 */
+	err = pblk_submit_io(pblk, rqd);
+	if (err) {
+		struct nvm_tgt_dev *dev = pblk->dev;
+		struct nvm_geo *geo = &dev->geo;
+
+		pr_err("pblk: could not async erase line:%d,blk:%d\n",
+					pblk_dev_ppa_to_line(ppa),
+					pblk_dev_ppa_to_pos(geo, ppa));
+	}
+
+	return err;
+}
+
+struct pblk_line *pblk_line_get_data(struct pblk *pblk)
+{
+	return pblk->l_mg.data_line;
+}
+
+struct pblk_line *pblk_line_get_data_next(struct pblk *pblk)
+{
+	return pblk->l_mg.data_next;
+}
+
+int pblk_line_is_full(struct pblk_line *line)
+{
+	return (line->left_msecs == 0);
+}
+
+void pblk_line_close(struct pblk *pblk, struct pblk_line *line)
+{
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct list_head *move_list;
+
+	line->emeta->crc = cpu_to_le32(pblk_calc_emeta_crc(pblk, line->emeta));
+
+	if (pblk_line_submit_emeta_io(pblk, line, line->cur_sec, WRITE))
+		pr_err("pblk: line %d close I/O failed\n", line->id);
+
+	WARN(!bitmap_full(line->map_bitmap, line->sec_in_line),
+				"pblk: corrupt closed line %d\n", line->id);
+
+	spin_lock(&l_mg->free_lock);
+	WARN_ON(!test_and_clear_bit(line->meta_line, &l_mg->meta_bitmap));
+	spin_unlock(&l_mg->free_lock);
+
+	spin_lock(&l_mg->gc_lock);
+	spin_lock(&line->lock);
+	WARN_ON(line->state != PBLK_LINESTATE_OPEN);
+	line->state = PBLK_LINESTATE_CLOSED;
+	move_list = pblk_line_gc_list(pblk, line);
+
+	list_add_tail(&line->list, move_list);
+
+	mempool_free(line->map_bitmap, pblk->line_meta_pool);
+	line->map_bitmap = NULL;
+	line->smeta = NULL;
+	line->emeta = NULL;
+
+	spin_unlock(&line->lock);
+	spin_unlock(&l_mg->gc_lock);
+}
+
+void pblk_line_close_ws(struct work_struct *work)
+{
+	struct pblk_line_ws *line_ws = container_of(work, struct pblk_line_ws,
+									ws);
+	struct pblk *pblk = line_ws->pblk;
+	struct pblk_line *line = line_ws->line;
+
+	pblk_line_close(pblk, line);
+	mempool_free(line_ws, pblk->line_ws_pool);
+}
+
+void pblk_line_mark_bb(struct work_struct *work)
+{
+	struct pblk_line_ws *line_ws = container_of(work, struct pblk_line_ws,
+									ws);
+	struct pblk *pblk = line_ws->pblk;
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct ppa_addr *ppa = line_ws->priv;
+	int ret;
+
+	ret = nvm_set_tgt_bb_tbl(dev, ppa, 1, NVM_BLK_T_GRWN_BAD);
+	if (ret) {
+		struct pblk_line *line;
+		int pos;
+
+		line = &pblk->lines[pblk_dev_ppa_to_line(*ppa)];
+		pos = pblk_dev_ppa_to_pos(&dev->geo, *ppa);
+
+		pr_err("pblk: failed to mark bb, line:%d, pos:%d\n",
+				line->id, pos);
+	}
+
+	kfree(ppa);
+	mempool_free(line_ws, pblk->line_ws_pool);
+}
+
+void pblk_line_run_ws(struct pblk *pblk, struct pblk_line *line, void *priv,
+		      void (*work)(struct work_struct *))
+{
+	struct pblk_line_ws *line_ws;
+
+	line_ws = mempool_alloc(pblk->line_ws_pool, GFP_ATOMIC);
+	if (!line_ws)
+		return;
+
+	line_ws->pblk = pblk;
+	line_ws->line = line;
+	line_ws->priv = priv;
+
+	INIT_WORK(&line_ws->ws, work);
+	queue_work(pblk->kw_wq, &line_ws->ws);
+}
+
+void pblk_down_rq(struct pblk *pblk, struct ppa_addr *ppa_list, int nr_ppas,
+		  unsigned long *lun_bitmap)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_lun *rlun;
+	int lun_id = ppa_list[0].g.ch * geo->luns_per_chnl + ppa_list[0].g.lun;
+	int ret;
+
+	/*
+	 * Only send one inflight I/O per LUN. Since we map at a page
+	 * granurality, all ppas in the I/O will map to the same LUN
+	 */
+#ifdef CONFIG_NVM_DEBUG
+	int i;
+
+	for (i = 1; i < nr_ppas; i++)
+		WARN_ON(ppa_list[0].g.lun != ppa_list[i].g.lun ||
+				ppa_list[0].g.ch != ppa_list[i].g.ch);
+#endif
+	/* If the LUN has been locked for this same request, do no attempt to
+	 * lock it again
+	 */
+	if (test_and_set_bit(lun_id, lun_bitmap))
+		return;
+
+	rlun = &pblk->luns[lun_id];
+	ret = down_timeout(&rlun->wr_sem, msecs_to_jiffies(5000));
+	if (ret) {
+		switch (ret) {
+		case -ETIME:
+			pr_err("pblk: lun semaphore timed out\n");
+			break;
+		case -EINTR:
+			pr_err("pblk: lun semaphore timed out\n");
+			break;
+		}
+	}
+}
+
+void pblk_up_rq(struct pblk *pblk, struct ppa_addr *ppa_list, int nr_ppas,
+		unsigned long *lun_bitmap)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_lun *rlun;
+	int nr_luns = geo->nr_luns;
+	int bit = -1;
+
+	while ((bit = find_next_bit(lun_bitmap, nr_luns, bit + 1)) < nr_luns) {
+		rlun = &pblk->luns[bit];
+		up(&rlun->wr_sem);
+	}
+
+	kfree(lun_bitmap);
+}
+
+void pblk_update_map(struct pblk *pblk, sector_t lba, struct ppa_addr ppa)
+{
+	struct ppa_addr l2p_ppa;
+
+	/* logic error: lba out-of-bounds. Ignore update */
+	if (!(lba < pblk->rl.nr_secs)) {
+		WARN(1, "pblk: corrupted L2P map request\n");
+		return;
+	}
+
+	spin_lock(&pblk->trans_lock);
+	l2p_ppa = pblk_trans_map_get(pblk, lba);
+
+	if (!pblk_addr_in_cache(l2p_ppa) && !pblk_ppa_empty(l2p_ppa))
+		pblk_map_invalidate(pblk, l2p_ppa);
+
+	pblk_trans_map_set(pblk, lba, ppa);
+	spin_unlock(&pblk->trans_lock);
+}
+
+void pblk_update_map_cache(struct pblk *pblk, sector_t lba, struct ppa_addr ppa)
+{
+#ifdef CONFIG_NVM_DEBUG
+	/* Callers must ensure that the ppa points to a cache address */
+	BUG_ON(!pblk_addr_in_cache(ppa));
+	BUG_ON(pblk_rb_pos_oob(&pblk->rwb, pblk_addr_to_cacheline(ppa)));
+#endif
+
+	pblk_update_map(pblk, lba, ppa);
+}
+
+int pblk_update_map_gc(struct pblk *pblk, sector_t lba, struct ppa_addr ppa,
+		       struct pblk_line *gc_line)
+{
+	struct ppa_addr l2p_ppa;
+	int ret = 1;
+
+#ifdef CONFIG_NVM_DEBUG
+	/* Callers must ensure that the ppa points to a cache address */
+	BUG_ON(!pblk_addr_in_cache(ppa));
+	BUG_ON(pblk_rb_pos_oob(&pblk->rwb, pblk_addr_to_cacheline(ppa)));
+#endif
+
+	/* logic error: lba out-of-bounds. Ignore update */
+	if (!(lba < pblk->rl.nr_secs)) {
+		WARN(1, "pblk: corrupted L2P map request\n");
+		return 0;
+	}
+
+	spin_lock(&pblk->trans_lock);
+	l2p_ppa = pblk_trans_map_get(pblk, lba);
+
+	/* Prevent updated entries to be overwritten by GC */
+	if (pblk_addr_in_cache(l2p_ppa) || pblk_ppa_empty(l2p_ppa) ||
+				pblk_tgt_ppa_to_line(l2p_ppa) != gc_line->id) {
+		ret = 0;
+		goto out;
+	}
+
+	pblk_trans_map_set(pblk, lba, ppa);
+out:
+	spin_unlock(&pblk->trans_lock);
+	return ret;
+}
+
+void pblk_update_map_dev(struct pblk *pblk, sector_t lba, struct ppa_addr ppa,
+			 struct ppa_addr entry_line)
+{
+	struct ppa_addr l2p_line;
+
+#ifdef CONFIG_NVM_DEBUG
+	/* Callers must ensure that the ppa points to a device address */
+	BUG_ON(pblk_addr_in_cache(ppa));
+#endif
+	/* Invalidate and discard padded entries */
+	if (lba == ADDR_EMPTY) {
+#ifdef CONFIG_NVM_DEBUG
+		atomic_long_inc(&pblk->padded_wb);
+#endif
+		pblk_map_invalidate(pblk, ppa);
+		return;
+	}
+
+	/* logic error: lba out-of-bounds. Ignore update */
+	if (!(lba < pblk->rl.nr_secs)) {
+		WARN(1, "pblk: corrupted L2P map request\n");
+		return;
+	}
+
+	spin_lock(&pblk->trans_lock);
+	l2p_line = pblk_trans_map_get(pblk, lba);
+
+	/* Do not update L2P if the cacheline has been updated. In this case,
+	 * the mapped ppa must be invalidated
+	 */
+	if (l2p_line.ppa != entry_line.ppa) {
+		if (!pblk_ppa_empty(ppa))
+			pblk_map_invalidate(pblk, ppa);
+		goto out;
+	}
+
+#ifdef CONFIG_NVM_DEBUG
+	WARN_ON(!pblk_addr_in_cache(l2p_line) && !pblk_ppa_empty(l2p_line));
+#endif
+
+	pblk_trans_map_set(pblk, lba, ppa);
+out:
+	spin_unlock(&pblk->trans_lock);
+}
+
+void pblk_lookup_l2p_seq(struct pblk *pblk, struct ppa_addr *ppas,
+			 sector_t blba, int nr_secs)
+{
+	int i;
+
+	spin_lock(&pblk->trans_lock);
+	for (i = 0; i < nr_secs; i++)
+		ppas[i] = pblk_trans_map_get(pblk, blba + i);
+	spin_unlock(&pblk->trans_lock);
+}
+
+void pblk_lookup_l2p_rand(struct pblk *pblk, struct ppa_addr *ppas,
+			  u64 *lba_list, int nr_secs)
+{
+	sector_t lba;
+	int i;
+
+	spin_lock(&pblk->trans_lock);
+	for (i = 0; i < nr_secs; i++) {
+		lba = lba_list[i];
+		if (lba == ADDR_EMPTY) {
+			ppas[i].ppa = ADDR_EMPTY;
+		} else {
+			/* logic error: lba out-of-bounds. Ignore update */
+			if (!(lba < pblk->rl.nr_secs)) {
+				WARN(1, "pblk: corrupted L2P map request\n");
+				continue;
+			}
+			ppas[i] = pblk_trans_map_get(pblk, lba);
+		}
+	}
+	spin_unlock(&pblk->trans_lock);
+}

drivers/lightnvm/pblk-gc.c

+/*
+ * Copyright (C) 2016 CNEX Labs
+ * Initial release: Javier Gonzalez <javier@cnexlabs.com>
+ *                  Matias Bjorling <matias@cnexlabs.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * pblk-gc.c - pblk's garbage collector
+ */
+
+#include "pblk.h"
+#include <linux/delay.h>
+
+static void pblk_gc_free_gc_rq(struct pblk_gc_rq *gc_rq)
+{
+	kfree(gc_rq->data);
+	kfree(gc_rq->lba_list);
+	kfree(gc_rq);
+}
+
+static int pblk_gc_write(struct pblk *pblk)
+{
+	struct pblk_gc *gc = &pblk->gc;
+	struct pblk_gc_rq *gc_rq, *tgc_rq;
+	LIST_HEAD(w_list);
+
+	spin_lock(&gc->w_lock);
+	if (list_empty(&gc->w_list)) {
+		spin_unlock(&gc->w_lock);
+		return 1;
+	}
+
+	list_for_each_entry_safe(gc_rq, tgc_rq, &gc->w_list, list) {
+		list_move_tail(&gc_rq->list, &w_list);
+		gc->w_entries--;
+	}
+	spin_unlock(&gc->w_lock);
+
+	list_for_each_entry_safe(gc_rq, tgc_rq, &w_list, list) {
+		pblk_write_gc_to_cache(pblk, gc_rq->data, gc_rq->lba_list,
+				gc_rq->nr_secs, gc_rq->secs_to_gc,
+				gc_rq->line, PBLK_IOTYPE_GC);
+
+		kref_put(&gc_rq->line->ref, pblk_line_put);
+
+		list_del(&gc_rq->list);
+		pblk_gc_free_gc_rq(gc_rq);
+	}
+
+	return 0;
+}
+
+static void pblk_gc_writer_kick(struct pblk_gc *gc)
+{
+	wake_up_process(gc->gc_writer_ts);
+}
+
+/*
+ * Responsible for managing all memory related to a gc request. Also in case of
+ * failure
+ */
+static int pblk_gc_move_valid_secs(struct pblk *pblk, struct pblk_line *line,
+				   u64 *lba_list, unsigned int nr_secs)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_gc *gc = &pblk->gc;
+	struct pblk_gc_rq *gc_rq;
+	void *data;
+	unsigned int secs_to_gc;
+	int ret = NVM_IO_OK;
+
+	data = kmalloc(nr_secs * geo->sec_size, GFP_KERNEL);
+	if (!data) {
+		ret = NVM_IO_ERR;
+		goto free_lba_list;
+	}
+
+	/* Read from GC victim block */
+	if (pblk_submit_read_gc(pblk, lba_list, data, nr_secs,
+							&secs_to_gc, line)) {
+		ret = NVM_IO_ERR;
+		goto free_data;
+	}
+
+	if (!secs_to_gc)
+		goto free_data;
+
+	gc_rq = kmalloc(sizeof(struct pblk_gc_rq), GFP_KERNEL);
+	if (!gc_rq) {
+		ret = NVM_IO_ERR;
+		goto free_data;
+	}
+
+	gc_rq->line = line;
+	gc_rq->data = data;
+	gc_rq->lba_list = lba_list;
+	gc_rq->nr_secs = nr_secs;
+	gc_rq->secs_to_gc = secs_to_gc;
+
+	kref_get(&line->ref);
+
+retry:
+	spin_lock(&gc->w_lock);
+	if (gc->w_entries > 256) {
+		spin_unlock(&gc->w_lock);
+		usleep_range(256, 1024);
+		goto retry;
+	}
+	gc->w_entries++;
+	list_add_tail(&gc_rq->list, &gc->w_list);
+	spin_unlock(&gc->w_lock);
+
+	pblk_gc_writer_kick(&pblk->gc);
+
+	return NVM_IO_OK;
+
+free_data:
+	kfree(data);
+free_lba_list:
+	kfree(lba_list);
+
+	return ret;
+}
+
+static void pblk_put_line_back(struct pblk *pblk, struct pblk_line *line)
+{
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct list_head *move_list;
+
+	spin_lock(&line->lock);
+	WARN_ON(line->state != PBLK_LINESTATE_GC);
+	line->state = PBLK_LINESTATE_CLOSED;
+	move_list = pblk_line_gc_list(pblk, line);
+	spin_unlock(&line->lock);
+
+	if (move_list) {
+		spin_lock(&l_mg->gc_lock);
+		list_add_tail(&line->list, move_list);
+		spin_unlock(&l_mg->gc_lock);
+	}
+}
+
+static void pblk_gc_line_ws(struct work_struct *work)
+{
+	struct pblk_line_ws *line_ws = container_of(work, struct pblk_line_ws,
+									ws);
+	struct pblk *pblk = line_ws->pblk;
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct pblk_line *line = line_ws->line;
+	struct pblk_line_meta *lm = &pblk->lm;
+	__le64 *lba_list = line_ws->priv;
+	u64 *gc_list;
+	int sec_left;
+	int nr_ppas, bit;
+	int put_line = 1;
+
+	pr_debug("pblk: line '%d' being reclaimed for GC\n", line->id);
+
+	spin_lock(&line->lock);
+	sec_left = line->vsc;
+	if (!sec_left) {
+		/* Lines are erased before being used (l_mg->data_/log_next) */
+		spin_unlock(&line->lock);
+		goto out;
+	}
+	spin_unlock(&line->lock);
+
+	if (sec_left < 0) {
+		pr_err("pblk: corrupted GC line (%d)\n", line->id);
+		put_line = 0;
+		pblk_put_line_back(pblk, line);
+		goto out;
+	}
+
+	bit = -1;
+next_rq:
+	gc_list = kmalloc_array(pblk->max_write_pgs, sizeof(u64), GFP_KERNEL);
+	if (!gc_list) {
+		put_line = 0;
+		pblk_put_line_back(pblk, line);
+		goto out;
+	}
+
+	nr_ppas = 0;
+	do {
+		bit = find_next_zero_bit(line->invalid_bitmap, lm->sec_per_line,
+								bit + 1);
+		if (bit > line->emeta_ssec)
+			break;
+
+		gc_list[nr_ppas++] = le64_to_cpu(lba_list[bit]);
+	} while (nr_ppas < pblk->max_write_pgs);
+
+	if (unlikely(!nr_ppas)) {
+		kfree(gc_list);
+		goto out;
+	}
+
+	if (pblk_gc_move_valid_secs(pblk, line, gc_list, nr_ppas)) {
+		pr_err("pblk: could not GC all sectors: line:%d (%d/%d/%d)\n",
+						line->id, line->vsc,
+						nr_ppas, nr_ppas);
+		put_line = 0;
+		pblk_put_line_back(pblk, line);
+		goto out;
+	}
+
+	sec_left -= nr_ppas;
+	if (sec_left > 0)
+		goto next_rq;
+
+out:
+	pblk_mfree(line->emeta, l_mg->emeta_alloc_type);
+	mempool_free(line_ws, pblk->line_ws_pool);
+	atomic_dec(&pblk->gc.inflight_gc);
+	if (put_line)
+		kref_put(&line->ref, pblk_line_put);
+}
+
+static int pblk_gc_line(struct pblk *pblk, struct pblk_line *line)
+{
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct pblk_line_ws *line_ws;
+	__le64 *lba_list;
+	int ret;
+
+	line_ws = mempool_alloc(pblk->line_ws_pool, GFP_KERNEL);
+	line->emeta = pblk_malloc(lm->emeta_len, l_mg->emeta_alloc_type,
+								GFP_KERNEL);
+	if (!line->emeta) {
+		pr_err("pblk: cannot use GC emeta\n");
+		goto fail_free_ws;
+	}
+
+	ret = pblk_line_read_emeta(pblk, line);
+	if (ret) {
+		pr_err("pblk: line %d read emeta failed (%d)\n", line->id, ret);
+		goto fail_free_emeta;
+	}
+
+	/* If this read fails, it means that emeta is corrupted. For now, leave
+	 * the line untouched. TODO: Implement a recovery routine that scans and
+	 * moves all sectors on the line.
+	 */
+	lba_list = pblk_recov_get_lba_list(pblk, line->emeta);
+	if (!lba_list) {
+		pr_err("pblk: could not interpret emeta (line %d)\n", line->id);
+		goto fail_free_emeta;
+	}
+
+	line_ws->pblk = pblk;
+	line_ws->line = line;
+	line_ws->priv = lba_list;
+
+	INIT_WORK(&line_ws->ws, pblk_gc_line_ws);
+	queue_work(pblk->gc.gc_reader_wq, &line_ws->ws);
+
+	return 0;
+
+fail_free_emeta:
+	pblk_mfree(line->emeta, l_mg->emeta_alloc_type);
+fail_free_ws:
+	mempool_free(line_ws, pblk->line_ws_pool);
+	pblk_put_line_back(pblk, line);
+
+	return 1;
+}
+
+static void pblk_gc_lines(struct pblk *pblk, struct list_head *gc_list)
+{
+	struct pblk_line *line, *tline;
+
+	list_for_each_entry_safe(line, tline, gc_list, list) {
+		if (pblk_gc_line(pblk, line))
+			pr_err("pblk: failed to GC line %d\n", line->id);
+		list_del(&line->list);
+	}
+}
+
+/*
+ * Lines with no valid sectors will be returned to the free list immediately. If
+ * GC is activated - either because the free block count is under the determined
+ * threshold, or because it is being forced from user space - only lines with a
+ * high count of invalid sectors will be recycled.
+ */
+static void pblk_gc_run(struct pblk *pblk)
+{
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct pblk_gc *gc = &pblk->gc;
+	struct pblk_line *line, *tline;
+	unsigned int nr_blocks_free, nr_blocks_need;
+	struct list_head *group_list;
+	int run_gc, gc_group = 0;
+	int prev_gc = 0;
+	int inflight_gc = atomic_read(&gc->inflight_gc);
+	LIST_HEAD(gc_list);
+
+	spin_lock(&l_mg->gc_lock);
+	list_for_each_entry_safe(line, tline, &l_mg->gc_full_list, list) {
+		spin_lock(&line->lock);
+		WARN_ON(line->state != PBLK_LINESTATE_CLOSED);
+		line->state = PBLK_LINESTATE_GC;
+		spin_unlock(&line->lock);
+
+		list_del(&line->list);
+		kref_put(&line->ref, pblk_line_put);
+	}
+	spin_unlock(&l_mg->gc_lock);
+
+	nr_blocks_need = pblk_rl_gc_thrs(&pblk->rl);
+	nr_blocks_free = pblk_rl_nr_free_blks(&pblk->rl);
+	run_gc = (nr_blocks_need > nr_blocks_free || gc->gc_forced);
+
+next_gc_group:
+	group_list = l_mg->gc_lists[gc_group++];
+	spin_lock(&l_mg->gc_lock);
+	while (run_gc && !list_empty(group_list)) {
+		/* No need to queue up more GC lines than we can handle */
+		if (!run_gc || inflight_gc > gc->gc_jobs_active) {
+			spin_unlock(&l_mg->gc_lock);
+			pblk_gc_lines(pblk, &gc_list);
+			return;
+		}
+
+		line = list_first_entry(group_list, struct pblk_line, list);
+		nr_blocks_free += line->blk_in_line;
+
+		spin_lock(&line->lock);
+		WARN_ON(line->state != PBLK_LINESTATE_CLOSED);
+		line->state = PBLK_LINESTATE_GC;
+		list_move_tail(&line->list, &gc_list);
+		atomic_inc(&gc->inflight_gc);
+		inflight_gc++;
+		spin_unlock(&line->lock);
+
+		prev_gc = 1;
+		run_gc = (nr_blocks_need > nr_blocks_free || gc->gc_forced);
+	}
+	spin_unlock(&l_mg->gc_lock);
+
+	pblk_gc_lines(pblk, &gc_list);
+
+	if (!prev_gc && pblk->rl.rb_state > gc_group &&
+						gc_group < PBLK_NR_GC_LISTS)
+		goto next_gc_group;
+}
+
+
+static void pblk_gc_kick(struct pblk *pblk)
+{
+	struct pblk_gc *gc = &pblk->gc;
+
+	wake_up_process(gc->gc_ts);
+	pblk_gc_writer_kick(gc);
+	mod_timer(&gc->gc_timer, jiffies + msecs_to_jiffies(GC_TIME_MSECS));
+}
+
+static void pblk_gc_timer(unsigned long data)
+{
+	struct pblk *pblk = (struct pblk *)data;
+
+	pblk_gc_kick(pblk);
+}
+
+static int pblk_gc_ts(void *data)
+{
+	struct pblk *pblk = data;
+
+	while (!kthread_should_stop()) {
+		pblk_gc_run(pblk);
+		set_current_state(TASK_INTERRUPTIBLE);
+		io_schedule();
+	}
+
+	return 0;
+}
+
+static int pblk_gc_writer_ts(void *data)
+{
+	struct pblk *pblk = data;
+
+	while (!kthread_should_stop()) {
+		if (!pblk_gc_write(pblk))
+			continue;
+		set_current_state(TASK_INTERRUPTIBLE);
+		io_schedule();
+	}
+
+	return 0;
+}
+
+static void pblk_gc_start(struct pblk *pblk)
+{
+	pblk->gc.gc_active = 1;
+
+	pr_debug("pblk: gc start\n");
+}
+
+int pblk_gc_status(struct pblk *pblk)
+{
+	struct pblk_gc *gc = &pblk->gc;
+	int ret;
+
+	spin_lock(&gc->lock);
+	ret = gc->gc_active;
+	spin_unlock(&gc->lock);
+
+	return ret;
+}
+
+static void __pblk_gc_should_start(struct pblk *pblk)
+{
+	struct pblk_gc *gc = &pblk->gc;
+
+	lockdep_assert_held(&gc->lock);
+
+	if (gc->gc_enabled && !gc->gc_active)
+		pblk_gc_start(pblk);
+}
+
+void pblk_gc_should_start(struct pblk *pblk)
+{
+	struct pblk_gc *gc = &pblk->gc;
+
+	spin_lock(&gc->lock);
+	__pblk_gc_should_start(pblk);
+	spin_unlock(&gc->lock);
+}
+
+/*
+ * If flush_wq == 1 then no lock should be held by the caller since
+ * flush_workqueue can sleep
+ */
+static void pblk_gc_stop(struct pblk *pblk, int flush_wq)
+{
+	spin_lock(&pblk->gc.lock);
+	pblk->gc.gc_active = 0;
+	spin_unlock(&pblk->gc.lock);
+
+	pr_debug("pblk: gc stop\n");
+}
+
+void pblk_gc_should_stop(struct pblk *pblk)
+{
+	struct pblk_gc *gc = &pblk->gc;
+
+	if (gc->gc_active && !gc->gc_forced)
+		pblk_gc_stop(pblk, 0);
+}
+
+void pblk_gc_sysfs_state_show(struct pblk *pblk, int *gc_enabled,
+			      int *gc_active)
+{
+	struct pblk_gc *gc = &pblk->gc;
+
+	spin_lock(&gc->lock);
+	*gc_enabled = gc->gc_enabled;
+	*gc_active = gc->gc_active;
+	spin_unlock(&gc->lock);
+}
+
+void pblk_gc_sysfs_force(struct pblk *pblk, int force)
+{
+	struct pblk_gc *gc = &pblk->gc;
+	int rsv = 0;
+
+	spin_lock(&gc->lock);
+	if (force) {
+		gc->gc_enabled = 1;
+		rsv = 64;
+	}
+	pblk_rl_set_gc_rsc(&pblk->rl, rsv);
+	gc->gc_forced = force;
+	__pblk_gc_should_start(pblk);
+	spin_unlock(&gc->lock);
+}
+
+int pblk_gc_init(struct pblk *pblk)
+{
+	struct pblk_gc *gc = &pblk->gc;
+	int ret;
+
+	gc->gc_ts = kthread_create(pblk_gc_ts, pblk, "pblk-gc-ts");
+	if (IS_ERR(gc->gc_ts)) {
+		pr_err("pblk: could not allocate GC main kthread\n");
+		return PTR_ERR(gc->gc_ts);
+	}
+
+	gc->gc_writer_ts = kthread_create(pblk_gc_writer_ts, pblk,
+							"pblk-gc-writer-ts");
+	if (IS_ERR(gc->gc_writer_ts)) {
+		pr_err("pblk: could not allocate GC writer kthread\n");
+		ret = PTR_ERR(gc->gc_writer_ts);
+		goto fail_free_main_kthread;
+	}
+
+	setup_timer(&gc->gc_timer, pblk_gc_timer, (unsigned long)pblk);
+	mod_timer(&gc->gc_timer, jiffies + msecs_to_jiffies(GC_TIME_MSECS));
+
+	gc->gc_active = 0;
+	gc->gc_forced = 0;
+	gc->gc_enabled = 1;
+	gc->gc_jobs_active = 8;
+	gc->w_entries = 0;
+	atomic_set(&gc->inflight_gc, 0);
+
+	gc->gc_reader_wq = alloc_workqueue("pblk-gc-reader-wq",
+			WQ_MEM_RECLAIM | WQ_UNBOUND, gc->gc_jobs_active);
+	if (!gc->gc_reader_wq) {
+		pr_err("pblk: could not allocate GC reader workqueue\n");
+		ret = -ENOMEM;
+		goto fail_free_writer_kthread;
+	}
+
+	spin_lock_init(&gc->lock);
+	spin_lock_init(&gc->w_lock);
+	INIT_LIST_HEAD(&gc->w_list);
+
+	return 0;
+
+fail_free_main_kthread:
+	kthread_stop(gc->gc_ts);
+fail_free_writer_kthread:
+	kthread_stop(gc->gc_writer_ts);
+
+	return ret;
+}
+
+void pblk_gc_exit(struct pblk *pblk)
+{
+	struct pblk_gc *gc = &pblk->gc;
+
+	flush_workqueue(gc->gc_reader_wq);
+
+	del_timer(&gc->gc_timer);
+	pblk_gc_stop(pblk, 1);
+
+	if (gc->gc_ts)
+		kthread_stop(gc->gc_ts);
+
+	if (pblk->gc.gc_reader_wq)
+		destroy_workqueue(pblk->gc.gc_reader_wq);
+
+	if (gc->gc_writer_ts)
+		kthread_stop(gc->gc_writer_ts);
+}

drivers/lightnvm/pblk-init.c

+/*
+ * Copyright (C) 2015 IT University of Copenhagen (rrpc.c)
+ * Copyright (C) 2016 CNEX Labs
+ * Initial release: Javier Gonzalez <javier@cnexlabs.com>
+ *                  Matias Bjorling <matias@cnexlabs.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * Implementation of a physical block-device target for Open-channel SSDs.
+ *
+ * pblk-init.c - pblk's initialization.
+ */
+
+#include "pblk.h"
+
+static struct kmem_cache *pblk_blk_ws_cache, *pblk_rec_cache, *pblk_r_rq_cache,
+					*pblk_w_rq_cache, *pblk_line_meta_cache;
+static DECLARE_RWSEM(pblk_lock);
+
+static int pblk_rw_io(struct request_queue *q, struct pblk *pblk,
+			  struct bio *bio)
+{
+	int ret;
+
+	/* Read requests must be <= 256kb due to NVMe's 64 bit completion bitmap
+	 * constraint. Writes can be of arbitrary size.
+	 */
+	if (bio_data_dir(bio) == READ) {
+		blk_queue_split(q, &bio, q->bio_split);
+		ret = pblk_submit_read(pblk, bio);
+		if (ret == NVM_IO_DONE && bio_flagged(bio, BIO_CLONED))
+			bio_put(bio);
+
+		return ret;
+	}
+
+	/* Prevent deadlock in the case of a modest LUN configuration and large
+	 * user I/Os. Unless stalled, the rate limiter leaves at least 256KB
+	 * available for user I/O.
+	 */
+	if (unlikely(pblk_get_secs(bio) >= pblk_rl_sysfs_rate_show(&pblk->rl)))
+		blk_queue_split(q, &bio, q->bio_split);
+
+	return pblk_write_to_cache(pblk, bio, PBLK_IOTYPE_USER);
+}
+
+static blk_qc_t pblk_make_rq(struct request_queue *q, struct bio *bio)
+{
+	struct pblk *pblk = q->queuedata;
+
+	if (bio_op(bio) == REQ_OP_DISCARD) {
+		pblk_discard(pblk, bio);
+		if (!(bio->bi_opf & REQ_PREFLUSH)) {
+			bio_endio(bio);
+			return BLK_QC_T_NONE;
+		}
+	}
+
+	switch (pblk_rw_io(q, pblk, bio)) {
+	case NVM_IO_ERR:
+		bio_io_error(bio);
+		break;
+	case NVM_IO_DONE:
+		bio_endio(bio);
+		break;
+	}
+
+	return BLK_QC_T_NONE;
+}
+
+static void pblk_l2p_free(struct pblk *pblk)
+{
+	vfree(pblk->trans_map);
+}
+
+static int pblk_l2p_init(struct pblk *pblk)
+{
+	sector_t i;
+	struct ppa_addr ppa;
+	int entry_size = 8;
+
+	if (pblk->ppaf_bitsize < 32)
+		entry_size = 4;
+
+	pblk->trans_map = vmalloc(entry_size * pblk->rl.nr_secs);
+	if (!pblk->trans_map)
+		return -ENOMEM;
+
+	pblk_ppa_set_empty(&ppa);
+
+	for (i = 0; i < pblk->rl.nr_secs; i++)
+		pblk_trans_map_set(pblk, i, ppa);
+
+	return 0;
+}
+
+static void pblk_rwb_free(struct pblk *pblk)
+{
+	if (pblk_rb_tear_down_check(&pblk->rwb))
+		pr_err("pblk: write buffer error on tear down\n");
+
+	pblk_rb_data_free(&pblk->rwb);
+	vfree(pblk_rb_entries_ref(&pblk->rwb));
+}
+
+static int pblk_rwb_init(struct pblk *pblk)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_rb_entry *entries;
+	unsigned long nr_entries;
+	unsigned int power_size, power_seg_sz;
+
+	nr_entries = pblk_rb_calculate_size(pblk->pgs_in_buffer);
+
+	entries = vzalloc(nr_entries * sizeof(struct pblk_rb_entry));
+	if (!entries)
+		return -ENOMEM;
+
+	power_size = get_count_order(nr_entries);
+	power_seg_sz = get_count_order(geo->sec_size);
+
+	return pblk_rb_init(&pblk->rwb, entries, power_size, power_seg_sz);
+}
+
+/* Minimum pages needed within a lun */
+#define PAGE_POOL_SIZE 16
+#define ADDR_POOL_SIZE 64
+
+static int pblk_set_ppaf(struct pblk *pblk)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct nvm_addr_format ppaf = geo->ppaf;
+	int power_len;
+
+	/* Re-calculate channel and lun format to adapt to configuration */
+	power_len = get_count_order(geo->nr_chnls);
+	if (1 << power_len != geo->nr_chnls) {
+		pr_err("pblk: supports only power-of-two channel config.\n");
+		return -EINVAL;
+	}
+	ppaf.ch_len = power_len;
+
+	power_len = get_count_order(geo->luns_per_chnl);
+	if (1 << power_len != geo->luns_per_chnl) {
+		pr_err("pblk: supports only power-of-two LUN config.\n");
+		return -EINVAL;
+	}
+	ppaf.lun_len = power_len;
+
+	pblk->ppaf.sec_offset = 0;
+	pblk->ppaf.pln_offset = ppaf.sect_len;
+	pblk->ppaf.ch_offset = pblk->ppaf.pln_offset + ppaf.pln_len;
+	pblk->ppaf.lun_offset = pblk->ppaf.ch_offset + ppaf.ch_len;
+	pblk->ppaf.pg_offset = pblk->ppaf.lun_offset + ppaf.lun_len;
+	pblk->ppaf.blk_offset = pblk->ppaf.pg_offset + ppaf.pg_len;
+	pblk->ppaf.sec_mask = (1ULL << ppaf.sect_len) - 1;
+	pblk->ppaf.pln_mask = ((1ULL << ppaf.pln_len) - 1) <<
+							pblk->ppaf.pln_offset;
+	pblk->ppaf.ch_mask = ((1ULL << ppaf.ch_len) - 1) <<
+							pblk->ppaf.ch_offset;
+	pblk->ppaf.lun_mask = ((1ULL << ppaf.lun_len) - 1) <<
+							pblk->ppaf.lun_offset;
+	pblk->ppaf.pg_mask = ((1ULL << ppaf.pg_len) - 1) <<
+							pblk->ppaf.pg_offset;
+	pblk->ppaf.blk_mask = ((1ULL << ppaf.blk_len) - 1) <<
+							pblk->ppaf.blk_offset;
+
+	pblk->ppaf_bitsize = pblk->ppaf.blk_offset + ppaf.blk_len;
+
+	return 0;
+}
+
+static int pblk_init_global_caches(struct pblk *pblk)
+{
+	char cache_name[PBLK_CACHE_NAME_LEN];
+
+	down_write(&pblk_lock);
+	pblk_blk_ws_cache = kmem_cache_create("pblk_blk_ws",
+				sizeof(struct pblk_line_ws), 0, 0, NULL);
+	if (!pblk_blk_ws_cache) {
+		up_write(&pblk_lock);
+		return -ENOMEM;
+	}
+
+	pblk_rec_cache = kmem_cache_create("pblk_rec",
+				sizeof(struct pblk_rec_ctx), 0, 0, NULL);
+	if (!pblk_rec_cache) {
+		kmem_cache_destroy(pblk_blk_ws_cache);
+		up_write(&pblk_lock);
+		return -ENOMEM;
+	}
+
+	pblk_r_rq_cache = kmem_cache_create("pblk_r_rq", pblk_r_rq_size,
+				0, 0, NULL);
+	if (!pblk_r_rq_cache) {
+		kmem_cache_destroy(pblk_blk_ws_cache);
+		kmem_cache_destroy(pblk_rec_cache);
+		up_write(&pblk_lock);
+		return -ENOMEM;
+	}
+
+	pblk_w_rq_cache = kmem_cache_create("pblk_w_rq", pblk_w_rq_size,
+				0, 0, NULL);
+	if (!pblk_w_rq_cache) {
+		kmem_cache_destroy(pblk_blk_ws_cache);
+		kmem_cache_destroy(pblk_rec_cache);
+		kmem_cache_destroy(pblk_r_rq_cache);
+		up_write(&pblk_lock);
+		return -ENOMEM;
+	}
+
+	snprintf(cache_name, sizeof(cache_name), "pblk_line_m_%s",
+							pblk->disk->disk_name);
+	pblk_line_meta_cache = kmem_cache_create(cache_name,
+				pblk->lm.sec_bitmap_len, 0, 0, NULL);
+	if (!pblk_line_meta_cache) {
+		kmem_cache_destroy(pblk_blk_ws_cache);
+		kmem_cache_destroy(pblk_rec_cache);
+		kmem_cache_destroy(pblk_r_rq_cache);
+		kmem_cache_destroy(pblk_w_rq_cache);
+		up_write(&pblk_lock);
+		return -ENOMEM;
+	}
+	up_write(&pblk_lock);
+
+	return 0;
+}
+
+static int pblk_core_init(struct pblk *pblk)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	int max_write_ppas;
+	int mod;
+
+	pblk->min_write_pgs = geo->sec_per_pl * (geo->sec_size / PAGE_SIZE);
+	max_write_ppas = pblk->min_write_pgs * geo->nr_luns;
+	pblk->max_write_pgs = (max_write_ppas < nvm_max_phys_sects(dev)) ?
+				max_write_ppas : nvm_max_phys_sects(dev);
+	pblk->pgs_in_buffer = NVM_MEM_PAGE_WRITE * geo->sec_per_pg *
+						geo->nr_planes * geo->nr_luns;
+
+	if (pblk->max_write_pgs > PBLK_MAX_REQ_ADDRS) {
+		pr_err("pblk: cannot support device max_phys_sect\n");
+		return -EINVAL;
+	}
+
+	div_u64_rem(geo->sec_per_blk, pblk->min_write_pgs, &mod);
+	if (mod) {
+		pr_err("pblk: bad configuration of sectors/pages\n");
+		return -EINVAL;
+	}
+
+	if (pblk_init_global_caches(pblk))
+		return -ENOMEM;
+
+	pblk->page_pool = mempool_create_page_pool(PAGE_POOL_SIZE, 0);
+	if (!pblk->page_pool)
+		return -ENOMEM;
+
+	pblk->line_ws_pool = mempool_create_slab_pool(geo->nr_luns,
+							pblk_blk_ws_cache);
+	if (!pblk->line_ws_pool)
+		goto free_page_pool;
+
+	pblk->rec_pool = mempool_create_slab_pool(geo->nr_luns, pblk_rec_cache);
+	if (!pblk->rec_pool)
+		goto free_blk_ws_pool;
+
+	pblk->r_rq_pool = mempool_create_slab_pool(64, pblk_r_rq_cache);
+	if (!pblk->r_rq_pool)
+		goto free_rec_pool;
+
+	pblk->w_rq_pool = mempool_create_slab_pool(64, pblk_w_rq_cache);
+	if (!pblk->w_rq_pool)
+		goto free_r_rq_pool;
+
+	pblk->line_meta_pool =
+			mempool_create_slab_pool(16, pblk_line_meta_cache);
+	if (!pblk->line_meta_pool)
+		goto free_w_rq_pool;
+
+	pblk->kw_wq = alloc_workqueue("pblk-aux-wq",
+					WQ_MEM_RECLAIM | WQ_UNBOUND, 1);
+	if (!pblk->kw_wq)
+		goto free_line_meta_pool;
+
+	if (pblk_set_ppaf(pblk))
+		goto free_kw_wq;
+
+	if (pblk_rwb_init(pblk))
+		goto free_kw_wq;
+
+	INIT_LIST_HEAD(&pblk->compl_list);
+	return 0;
+
+free_kw_wq:
+	destroy_workqueue(pblk->kw_wq);
+free_line_meta_pool:
+	mempool_destroy(pblk->line_meta_pool);
+free_w_rq_pool:
+	mempool_destroy(pblk->w_rq_pool);
+free_r_rq_pool:
+	mempool_destroy(pblk->r_rq_pool);
+free_rec_pool:
+	mempool_destroy(pblk->rec_pool);
+free_blk_ws_pool:
+	mempool_destroy(pblk->line_ws_pool);
+free_page_pool:
+	mempool_destroy(pblk->page_pool);
+	return -ENOMEM;
+}
+
+static void pblk_core_free(struct pblk *pblk)
+{
+	if (pblk->kw_wq)
+		destroy_workqueue(pblk->kw_wq);
+
+	mempool_destroy(pblk->page_pool);
+	mempool_destroy(pblk->line_ws_pool);
+	mempool_destroy(pblk->rec_pool);
+	mempool_destroy(pblk->r_rq_pool);
+	mempool_destroy(pblk->w_rq_pool);
+	mempool_destroy(pblk->line_meta_pool);
+
+	kmem_cache_destroy(pblk_blk_ws_cache);
+	kmem_cache_destroy(pblk_rec_cache);
+	kmem_cache_destroy(pblk_r_rq_cache);
+	kmem_cache_destroy(pblk_w_rq_cache);
+	kmem_cache_destroy(pblk_line_meta_cache);
+}
+
+static void pblk_luns_free(struct pblk *pblk)
+{
+	kfree(pblk->luns);
+}
+
+static void pblk_lines_free(struct pblk *pblk)
+{
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct pblk_line *line;
+	int i;
+
+	spin_lock(&l_mg->free_lock);
+	for (i = 0; i < l_mg->nr_lines; i++) {
+		line = &pblk->lines[i];
+
+		pblk_line_free(pblk, line);
+		kfree(line->blk_bitmap);
+		kfree(line->erase_bitmap);
+	}
+	spin_unlock(&l_mg->free_lock);
+}
+
+static void pblk_line_meta_free(struct pblk *pblk)
+{
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	int i;
+
+	kfree(l_mg->bb_template);
+	kfree(l_mg->bb_aux);
+
+	for (i = 0; i < PBLK_DATA_LINES; i++) {
+		pblk_mfree(l_mg->sline_meta[i].meta, l_mg->smeta_alloc_type);
+		pblk_mfree(l_mg->eline_meta[i].meta, l_mg->emeta_alloc_type);
+	}
+
+	kfree(pblk->lines);
+}
+
+static int pblk_bb_discovery(struct nvm_tgt_dev *dev, struct pblk_lun *rlun)
+{
+	struct nvm_geo *geo = &dev->geo;
+	struct ppa_addr ppa;
+	u8 *blks;
+	int nr_blks, ret;
+
+	nr_blks = geo->blks_per_lun * geo->plane_mode;
+	blks = kmalloc(nr_blks, GFP_KERNEL);
+	if (!blks)
+		return -ENOMEM;
+
+	ppa.ppa = 0;
+	ppa.g.ch = rlun->bppa.g.ch;
+	ppa.g.lun = rlun->bppa.g.lun;
+
+	ret = nvm_get_tgt_bb_tbl(dev, ppa, blks);
+	if (ret)
+		goto out;
+
+	nr_blks = nvm_bb_tbl_fold(dev->parent, blks, nr_blks);
+	if (nr_blks < 0) {
+		kfree(blks);
+		ret = nr_blks;
+	}
+
+	rlun->bb_list = blks;
+
+out:
+	return ret;
+}
+
+static int pblk_bb_line(struct pblk *pblk, struct pblk_line *line)
+{
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct pblk_lun *rlun;
+	int bb_cnt = 0;
+	int i;
+
+	line->blk_bitmap = kzalloc(lm->blk_bitmap_len, GFP_KERNEL);
+	if (!line->blk_bitmap)
+		return -ENOMEM;
+
+	line->erase_bitmap = kzalloc(lm->blk_bitmap_len, GFP_KERNEL);
+	if (!line->erase_bitmap) {
+		kfree(line->blk_bitmap);
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < lm->blk_per_line; i++) {
+		rlun = &pblk->luns[i];
+		if (rlun->bb_list[line->id] == NVM_BLK_T_FREE)
+			continue;
+
+		set_bit(i, line->blk_bitmap);
+		bb_cnt++;
+	}
+
+	return bb_cnt;
+}
+
+static int pblk_luns_init(struct pblk *pblk, struct ppa_addr *luns)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_lun *rlun;
+	int i, ret;
+
+	/* TODO: Implement unbalanced LUN support */
+	if (geo->luns_per_chnl < 0) {
+		pr_err("pblk: unbalanced LUN config.\n");
+		return -EINVAL;
+	}
+
+	pblk->luns = kcalloc(geo->nr_luns, sizeof(struct pblk_lun), GFP_KERNEL);
+	if (!pblk->luns)
+		return -ENOMEM;
+
+	for (i = 0; i < geo->nr_luns; i++) {
+		/* Stripe across channels */
+		int ch = i % geo->nr_chnls;
+		int lun_raw = i / geo->nr_chnls;
+		int lunid = lun_raw + ch * geo->luns_per_chnl;
+
+		rlun = &pblk->luns[i];
+		rlun->bppa = luns[lunid];
+
+		sema_init(&rlun->wr_sem, 1);
+
+		ret = pblk_bb_discovery(dev, rlun);
+		if (ret) {
+			while (--i >= 0)
+				kfree(pblk->luns[i].bb_list);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int pblk_lines_configure(struct pblk *pblk, int flags)
+{
+	struct pblk_line *line = NULL;
+	int ret = 0;
+
+	if (!(flags & NVM_TARGET_FACTORY)) {
+		line = pblk_recov_l2p(pblk);
+		if (IS_ERR(line)) {
+			pr_err("pblk: could not recover l2p table\n");
+			ret = -EFAULT;
+		}
+	}
+
+	if (!line) {
+		/* Configure next line for user data */
+		line = pblk_line_get_first_data(pblk);
+		if (!line) {
+			pr_err("pblk: line list corrupted\n");
+			ret = -EFAULT;
+		}
+	}
+
+	return ret;
+}
+
+/* See comment over struct line_emeta definition */
+static unsigned int calc_emeta_len(struct pblk *pblk, struct pblk_line_meta *lm)
+{
+	return (sizeof(struct line_emeta) +
+			((lm->sec_per_line - lm->emeta_sec) * sizeof(u64)) +
+			(pblk->l_mg.nr_lines * sizeof(u32)) +
+			lm->blk_bitmap_len);
+}
+
+static void pblk_set_provision(struct pblk *pblk, long nr_free_blks)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	sector_t provisioned;
+
+	pblk->over_pct = 20;
+
+	provisioned = nr_free_blks;
+	provisioned *= (100 - pblk->over_pct);
+	sector_div(provisioned, 100);
+
+	/* Internally pblk manages all free blocks, but all calculations based
+	 * on user capacity consider only provisioned blocks
+	 */
+	pblk->rl.total_blocks = nr_free_blks;
+	pblk->rl.nr_secs = nr_free_blks * geo->sec_per_blk;
+	pblk->capacity = provisioned * geo->sec_per_blk;
+	atomic_set(&pblk->rl.free_blocks, nr_free_blks);
+}
+
+static int pblk_lines_init(struct pblk *pblk)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct pblk_line *line;
+	unsigned int smeta_len, emeta_len;
+	long nr_bad_blks, nr_meta_blks, nr_free_blks;
+	int bb_distance;
+	int i;
+	int ret = 0;
+
+	lm->sec_per_line = geo->sec_per_blk * geo->nr_luns;
+	lm->blk_per_line = geo->nr_luns;
+	lm->blk_bitmap_len = BITS_TO_LONGS(geo->nr_luns) * sizeof(long);
+	lm->sec_bitmap_len = BITS_TO_LONGS(lm->sec_per_line) * sizeof(long);
+	lm->lun_bitmap_len = BITS_TO_LONGS(geo->nr_luns) * sizeof(long);
+	lm->high_thrs = lm->sec_per_line / 2;
+	lm->mid_thrs = lm->sec_per_line / 4;
+
+	/* Calculate necessary pages for smeta. See comment over struct
+	 * line_smeta definition
+	 */
+	lm->smeta_len = sizeof(struct line_smeta) +
+				PBLK_LINE_NR_LUN_BITMAP * lm->lun_bitmap_len;
+
+	i = 1;
+add_smeta_page:
+	lm->smeta_sec = i * geo->sec_per_pl;
+	lm->smeta_len = lm->smeta_sec * geo->sec_size;
+
+	smeta_len = sizeof(struct line_smeta) +
+				PBLK_LINE_NR_LUN_BITMAP * lm->lun_bitmap_len;
+	if (smeta_len > lm->smeta_len) {
+		i++;
+		goto add_smeta_page;
+	}
+
+	/* Calculate necessary pages for emeta. See comment over struct
+	 * line_emeta definition
+	 */
+	i = 1;
+add_emeta_page:
+	lm->emeta_sec = i * geo->sec_per_pl;
+	lm->emeta_len = lm->emeta_sec * geo->sec_size;
+
+	emeta_len = calc_emeta_len(pblk, lm);
+	if (emeta_len > lm->emeta_len) {
+		i++;
+		goto add_emeta_page;
+	}
+	lm->emeta_bb = geo->nr_luns - i;
+
+	nr_meta_blks = (lm->smeta_sec + lm->emeta_sec +
+				(geo->sec_per_blk / 2)) / geo->sec_per_blk;
+	lm->min_blk_line = nr_meta_blks + 1;
+
+	l_mg->nr_lines = geo->blks_per_lun;
+	l_mg->log_line = l_mg->data_line = NULL;
+	l_mg->l_seq_nr = l_mg->d_seq_nr = 0;
+	l_mg->nr_free_lines = 0;
+	bitmap_zero(&l_mg->meta_bitmap, PBLK_DATA_LINES);
+
+	/* smeta is always small enough to fit on a kmalloc memory allocation,
+	 * emeta depends on the number of LUNs allocated to the pblk instance
+	 */
+	l_mg->smeta_alloc_type = PBLK_KMALLOC_META;
+	for (i = 0; i < PBLK_DATA_LINES; i++) {
+		l_mg->sline_meta[i].meta = kmalloc(lm->smeta_len, GFP_KERNEL);
+		if (!l_mg->sline_meta[i].meta)
+			while (--i >= 0) {
+				kfree(l_mg->sline_meta[i].meta);
+				ret = -ENOMEM;
+				goto fail;
+			}
+	}
+
+	if (lm->emeta_len > KMALLOC_MAX_CACHE_SIZE) {
+		l_mg->emeta_alloc_type = PBLK_VMALLOC_META;
+
+		for (i = 0; i < PBLK_DATA_LINES; i++) {
+			l_mg->eline_meta[i].meta = vmalloc(lm->emeta_len);
+			if (!l_mg->eline_meta[i].meta)
+				while (--i >= 0) {
+					vfree(l_mg->eline_meta[i].meta);
+					ret = -ENOMEM;
+					goto fail;
+				}
+		}
+	} else {
+		l_mg->emeta_alloc_type = PBLK_KMALLOC_META;
+
+		for (i = 0; i < PBLK_DATA_LINES; i++) {
+			l_mg->eline_meta[i].meta =
+					kmalloc(lm->emeta_len, GFP_KERNEL);
+			if (!l_mg->eline_meta[i].meta)
+				while (--i >= 0) {
+					kfree(l_mg->eline_meta[i].meta);
+					ret = -ENOMEM;
+					goto fail;
+				}
+		}
+	}
+
+	l_mg->bb_template = kzalloc(lm->sec_bitmap_len, GFP_KERNEL);
+	if (!l_mg->bb_template)
+		goto fail_free_meta;
+
+	l_mg->bb_aux = kzalloc(lm->sec_bitmap_len, GFP_KERNEL);
+	if (!l_mg->bb_aux)
+		goto fail_free_bb_template;
+
+	bb_distance = (geo->nr_luns) * geo->sec_per_pl;
+	for (i = 0; i < lm->sec_per_line; i += bb_distance)
+		bitmap_set(l_mg->bb_template, i, geo->sec_per_pl);
+
+	INIT_LIST_HEAD(&l_mg->free_list);
+	INIT_LIST_HEAD(&l_mg->corrupt_list);
+	INIT_LIST_HEAD(&l_mg->bad_list);
+	INIT_LIST_HEAD(&l_mg->gc_full_list);
+	INIT_LIST_HEAD(&l_mg->gc_high_list);
+	INIT_LIST_HEAD(&l_mg->gc_mid_list);
+	INIT_LIST_HEAD(&l_mg->gc_low_list);
+	INIT_LIST_HEAD(&l_mg->gc_empty_list);
+
+	l_mg->gc_lists[0] = &l_mg->gc_high_list;
+	l_mg->gc_lists[1] = &l_mg->gc_mid_list;
+	l_mg->gc_lists[2] = &l_mg->gc_low_list;
+
+	spin_lock_init(&l_mg->free_lock);
+	spin_lock_init(&l_mg->gc_lock);
+
+	pblk->lines = kcalloc(l_mg->nr_lines, sizeof(struct pblk_line),
+								GFP_KERNEL);
+	if (!pblk->lines)
+		goto fail_free_bb_aux;
+
+	nr_free_blks = 0;
+	for (i = 0; i < l_mg->nr_lines; i++) {
+		line = &pblk->lines[i];
+
+		line->pblk = pblk;
+		line->id = i;
+		line->type = PBLK_LINETYPE_FREE;
+		line->state = PBLK_LINESTATE_FREE;
+		line->gc_group = PBLK_LINEGC_NONE;
+		spin_lock_init(&line->lock);
+
+		nr_bad_blks = pblk_bb_line(pblk, line);
+		if (nr_bad_blks < 0 || nr_bad_blks > lm->blk_per_line)
+			goto fail_free_lines;
+
+		line->blk_in_line = lm->blk_per_line - nr_bad_blks;
+		if (line->blk_in_line < lm->min_blk_line) {
+			line->state = PBLK_LINESTATE_BAD;
+			list_add_tail(&line->list, &l_mg->bad_list);
+			continue;
+		}
+
+		nr_free_blks += line->blk_in_line;
+
+		l_mg->nr_free_lines++;
+		list_add_tail(&line->list, &l_mg->free_list);
+	}
+
+	pblk_set_provision(pblk, nr_free_blks);
+
+	sema_init(&pblk->erase_sem, 1);
+
+	/* Cleanup per-LUN bad block lists - managed within lines on run-time */
+	for (i = 0; i < geo->nr_luns; i++)
+		kfree(pblk->luns[i].bb_list);
+
+	return 0;
+fail_free_lines:
+	kfree(pblk->lines);
+fail_free_bb_aux:
+	kfree(l_mg->bb_aux);
+fail_free_bb_template:
+	kfree(l_mg->bb_template);
+fail_free_meta:
+	for (i = 0; i < PBLK_DATA_LINES; i++) {
+		pblk_mfree(l_mg->sline_meta[i].meta, l_mg->smeta_alloc_type);
+		pblk_mfree(l_mg->eline_meta[i].meta, l_mg->emeta_alloc_type);
+	}
+fail:
+	for (i = 0; i < geo->nr_luns; i++)
+		kfree(pblk->luns[i].bb_list);
+
+	return ret;
+}
+
+static int pblk_writer_init(struct pblk *pblk)
+{
+	setup_timer(&pblk->wtimer, pblk_write_timer_fn, (unsigned long)pblk);
+	mod_timer(&pblk->wtimer, jiffies + msecs_to_jiffies(100));
+
+	pblk->writer_ts = kthread_create(pblk_write_ts, pblk, "pblk-writer-t");
+	if (IS_ERR(pblk->writer_ts)) {
+		pr_err("pblk: could not allocate writer kthread\n");
+		return 1;
+	}
+
+	return 0;
+}
+
+static void pblk_writer_stop(struct pblk *pblk)
+{
+	if (pblk->writer_ts)
+		kthread_stop(pblk->writer_ts);
+	del_timer(&pblk->wtimer);
+}
+
+static void pblk_free(struct pblk *pblk)
+{
+	pblk_luns_free(pblk);
+	pblk_lines_free(pblk);
+	pblk_line_meta_free(pblk);
+	pblk_core_free(pblk);
+	pblk_l2p_free(pblk);
+
+	kfree(pblk);
+}
+
+static void pblk_tear_down(struct pblk *pblk)
+{
+	pblk_flush_writer(pblk);
+	pblk_writer_stop(pblk);
+	pblk_rb_sync_l2p(&pblk->rwb);
+	pblk_recov_pad(pblk);
+	pblk_rwb_free(pblk);
+	pblk_rl_free(&pblk->rl);
+
+	pr_debug("pblk: consistent tear down\n");
+}
+
+static void pblk_exit(void *private)
+{
+	struct pblk *pblk = private;
+
+	down_write(&pblk_lock);
+	pblk_gc_exit(pblk);
+	pblk_tear_down(pblk);
+	pblk_free(pblk);
+	up_write(&pblk_lock);
+}
+
+static sector_t pblk_capacity(void *private)
+{
+	struct pblk *pblk = private;
+
+	return pblk->capacity * NR_PHY_IN_LOG;
+}
+
+static void *pblk_init(struct nvm_tgt_dev *dev, struct gendisk *tdisk,
+		       int flags)
+{
+	struct nvm_geo *geo = &dev->geo;
+	struct request_queue *bqueue = dev->q;
+	struct request_queue *tqueue = tdisk->queue;
+	struct pblk *pblk;
+	int ret;
+
+	if (dev->identity.dom & NVM_RSP_L2P) {
+		pr_err("pblk: device-side L2P table not supported. (%x)\n",
+							dev->identity.dom);
+		return ERR_PTR(-EINVAL);
+	}
+
+	pblk = kzalloc(sizeof(struct pblk), GFP_KERNEL);
+	if (!pblk)
+		return ERR_PTR(-ENOMEM);
+
+	pblk->dev = dev;
+	pblk->disk = tdisk;
+
+	spin_lock_init(&pblk->trans_lock);
+	spin_lock_init(&pblk->lock);
+
+	if (flags & NVM_TARGET_FACTORY)
+		pblk_setup_uuid(pblk);
+
+#ifdef CONFIG_NVM_DEBUG
+	atomic_long_set(&pblk->inflight_writes, 0);
+	atomic_long_set(&pblk->padded_writes, 0);
+	atomic_long_set(&pblk->padded_wb, 0);
+	atomic_long_set(&pblk->nr_flush, 0);
+	atomic_long_set(&pblk->req_writes, 0);
+	atomic_long_set(&pblk->sub_writes, 0);
+	atomic_long_set(&pblk->sync_writes, 0);
+	atomic_long_set(&pblk->compl_writes, 0);
+	atomic_long_set(&pblk->inflight_reads, 0);
+	atomic_long_set(&pblk->sync_reads, 0);
+	atomic_long_set(&pblk->recov_writes, 0);
+	atomic_long_set(&pblk->recov_writes, 0);
+	atomic_long_set(&pblk->recov_gc_writes, 0);
+#endif
+
+	atomic_long_set(&pblk->read_failed, 0);
+	atomic_long_set(&pblk->read_empty, 0);
+	atomic_long_set(&pblk->read_high_ecc, 0);
+	atomic_long_set(&pblk->read_failed_gc, 0);
+	atomic_long_set(&pblk->write_failed, 0);
+	atomic_long_set(&pblk->erase_failed, 0);
+
+	ret = pblk_luns_init(pblk, dev->luns);
+	if (ret) {
+		pr_err("pblk: could not initialize luns\n");
+		goto fail;
+	}
+
+	ret = pblk_lines_init(pblk);
+	if (ret) {
+		pr_err("pblk: could not initialize lines\n");
+		goto fail_free_luns;
+	}
+
+	ret = pblk_core_init(pblk);
+	if (ret) {
+		pr_err("pblk: could not initialize core\n");
+		goto fail_free_line_meta;
+	}
+
+	ret = pblk_l2p_init(pblk);
+	if (ret) {
+		pr_err("pblk: could not initialize maps\n");
+		goto fail_free_core;
+	}
+
+	ret = pblk_lines_configure(pblk, flags);
+	if (ret) {
+		pr_err("pblk: could not configure lines\n");
+		goto fail_free_l2p;
+	}
+
+	ret = pblk_writer_init(pblk);
+	if (ret) {
+		pr_err("pblk: could not initialize write thread\n");
+		goto fail_free_lines;
+	}
+
+	ret = pblk_gc_init(pblk);
+	if (ret) {
+		pr_err("pblk: could not initialize gc\n");
+		goto fail_stop_writer;
+	}
+
+	/* inherit the size from the underlying device */
+	blk_queue_logical_block_size(tqueue, queue_physical_block_size(bqueue));
+	blk_queue_max_hw_sectors(tqueue, queue_max_hw_sectors(bqueue));
+
+	blk_queue_write_cache(tqueue, true, false);
+
+	tqueue->limits.discard_granularity = geo->pgs_per_blk * geo->pfpg_size;
+	tqueue->limits.discard_alignment = 0;
+	blk_queue_max_discard_sectors(tqueue, UINT_MAX >> 9);
+	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, tqueue);
+
+	pr_info("pblk init: luns:%u, lines:%d, secs:%llu, buf entries:%u\n",
+			geo->nr_luns, pblk->l_mg.nr_lines,
+			(unsigned long long)pblk->rl.nr_secs,
+			pblk->rwb.nr_entries);
+
+	wake_up_process(pblk->writer_ts);
+	return pblk;
+
+fail_stop_writer:
+	pblk_writer_stop(pblk);
+fail_free_lines:
+	pblk_lines_free(pblk);
+fail_free_l2p:
+	pblk_l2p_free(pblk);
+fail_free_core:
+	pblk_core_free(pblk);
+fail_free_line_meta:
+	pblk_line_meta_free(pblk);
+fail_free_luns:
+	pblk_luns_free(pblk);
+fail:
+	kfree(pblk);
+	return ERR_PTR(ret);
+}
+
+/* physical block device target */
+static struct nvm_tgt_type tt_pblk = {
+	.name		= "pblk",
+	.version	= {1, 0, 0},
+
+	.make_rq	= pblk_make_rq,
+	.capacity	= pblk_capacity,
+
+	.init		= pblk_init,
+	.exit		= pblk_exit,
+
+	.sysfs_init	= pblk_sysfs_init,
+	.sysfs_exit	= pblk_sysfs_exit,
+};
+
+static int __init pblk_module_init(void)
+{
+	return nvm_register_tgt_type(&tt_pblk);
+}
+
+static void pblk_module_exit(void)
+{
+	nvm_unregister_tgt_type(&tt_pblk);
+}
+
+module_init(pblk_module_init);
+module_exit(pblk_module_exit);
+MODULE_AUTHOR("Javier Gonzalez <javier@cnexlabs.com>");
+MODULE_AUTHOR("Matias Bjorling <matias@cnexlabs.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Physical Block-Device for Open-Channel SSDs");

drivers/lightnvm/pblk-map.c

+/*
+ * Copyright (C) 2016 CNEX Labs
+ * Initial release: Javier Gonzalez <javier@cnexlabs.com>
+ *                  Matias Bjorling <matias@cnexlabs.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * pblk-map.c - pblk's lba-ppa mapping strategy
+ *
+ */
+
+#include "pblk.h"
+
+static void pblk_map_page_data(struct pblk *pblk, unsigned int sentry,
+			       struct ppa_addr *ppa_list,
+			       unsigned long *lun_bitmap,
+			       struct pblk_sec_meta *meta_list,
+			       unsigned int valid_secs)
+{
+	struct pblk_line *line = pblk_line_get_data(pblk);
+	struct line_emeta *emeta = line->emeta;
+	struct pblk_w_ctx *w_ctx;
+	__le64 *lba_list = pblk_line_emeta_to_lbas(emeta);
+	u64 paddr;
+	int nr_secs = pblk->min_write_pgs;
+	int i;
+
+	paddr = pblk_alloc_page(pblk, line, nr_secs);
+
+	for (i = 0; i < nr_secs; i++, paddr++) {
+		/* ppa to be sent to the device */
+		ppa_list[i] = addr_to_gen_ppa(pblk, paddr, line->id);
+
+		/* Write context for target bio completion on write buffer. Note
+		 * that the write buffer is protected by the sync backpointer,
+		 * and a single writer thread have access to each specific entry
+		 * at a time. Thus, it is safe to modify the context for the
+		 * entry we are setting up for submission without taking any
+		 * lock or memory barrier.
+		 */
+		if (i < valid_secs) {
+			kref_get(&line->ref);
+			w_ctx = pblk_rb_w_ctx(&pblk->rwb, sentry + i);
+			w_ctx->ppa = ppa_list[i];
+			meta_list[i].lba = cpu_to_le64(w_ctx->lba);
+			lba_list[paddr] = cpu_to_le64(w_ctx->lba);
+			le64_add_cpu(&line->emeta->nr_valid_lbas, 1);
+		} else {
+			meta_list[i].lba = cpu_to_le64(ADDR_EMPTY);
+			lba_list[paddr] = cpu_to_le64(ADDR_EMPTY);
+			pblk_map_pad_invalidate(pblk, line, paddr);
+		}
+	}
+
+	if (pblk_line_is_full(line)) {
+		line = pblk_line_replace_data(pblk);
+		if (!line)
+			return;
+	}
+
+	pblk_down_rq(pblk, ppa_list, nr_secs, lun_bitmap);
+}
+
+void pblk_map_rq(struct pblk *pblk, struct nvm_rq *rqd, unsigned int sentry,
+		 unsigned long *lun_bitmap, unsigned int valid_secs,
+		 unsigned int off)
+{
+	struct pblk_sec_meta *meta_list = rqd->meta_list;
+	unsigned int map_secs;
+	int min = pblk->min_write_pgs;
+	int i;
+
+	for (i = off; i < rqd->nr_ppas; i += min) {
+		map_secs = (i + min > valid_secs) ? (valid_secs % min) : min;
+		pblk_map_page_data(pblk, sentry + i, &rqd->ppa_list[i],
+					lun_bitmap, &meta_list[i], map_secs);
+	}
+}
+
+/* only if erase_ppa is set, acquire erase semaphore */
+void pblk_map_erase_rq(struct pblk *pblk, struct nvm_rq *rqd,
+		       unsigned int sentry, unsigned long *lun_bitmap,
+		       unsigned int valid_secs, struct ppa_addr *erase_ppa)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_line *e_line = pblk_line_get_data_next(pblk);
+	struct pblk_sec_meta *meta_list = rqd->meta_list;
+	unsigned int map_secs;
+	int min = pblk->min_write_pgs;
+	int i, erase_lun;
+
+	for (i = 0; i < rqd->nr_ppas; i += min) {
+		map_secs = (i + min > valid_secs) ? (valid_secs % min) : min;
+		pblk_map_page_data(pblk, sentry + i, &rqd->ppa_list[i],
+					lun_bitmap, &meta_list[i], map_secs);
+
+		erase_lun = rqd->ppa_list[i].g.lun * geo->nr_chnls +
+							rqd->ppa_list[i].g.ch;
+
+		if (!test_bit(erase_lun, e_line->erase_bitmap)) {
+			if (down_trylock(&pblk->erase_sem))
+				continue;
+
+			set_bit(erase_lun, e_line->erase_bitmap);
+			e_line->left_eblks--;
+			*erase_ppa = rqd->ppa_list[i];
+			erase_ppa->g.blk = e_line->id;
+
+			/* Avoid evaluating e_line->left_eblks */
+			return pblk_map_rq(pblk, rqd, sentry, lun_bitmap,
+							valid_secs, i + min);
+		}
+	}
+
+	/* Erase blocks that are bad in this line but might not be in next */
+	if (unlikely(ppa_empty(*erase_ppa))) {
+		struct pblk_line_meta *lm = &pblk->lm;
+
+		i = find_first_zero_bit(e_line->erase_bitmap, lm->blk_per_line);
+		if (i == lm->blk_per_line)
+			return;
+
+		set_bit(i, e_line->erase_bitmap);
+		e_line->left_eblks--;
+		*erase_ppa = pblk->luns[i].bppa; /* set ch and lun */
+		erase_ppa->g.blk = e_line->id;
+	}
+}

drivers/lightnvm/pblk-rb.c

+/*
+ * Copyright (C) 2016 CNEX Labs
+ * Initial release: Javier Gonzalez <javier@cnexlabs.com>
+ *
+ * Based upon the circular ringbuffer.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * pblk-rb.c - pblk's write buffer
+ */
+
+#include <linux/circ_buf.h>
+
+#include "pblk.h"
+
+static DECLARE_RWSEM(pblk_rb_lock);
+
+void pblk_rb_data_free(struct pblk_rb *rb)
+{
+	struct pblk_rb_pages *p, *t;
+
+	down_write(&pblk_rb_lock);
+	list_for_each_entry_safe(p, t, &rb->pages, list) {
+		free_pages((unsigned long)page_address(p->pages), p->order);
+		list_del(&p->list);
+		kfree(p);
+	}
+	up_write(&pblk_rb_lock);
+}
+
+/*
+ * Initialize ring buffer. The data and metadata buffers must be previously
+ * allocated and their size must be a power of two
+ * (Documentation/circular-buffers.txt)
+ */
+int pblk_rb_init(struct pblk_rb *rb, struct pblk_rb_entry *rb_entry_base,
+		 unsigned int power_size, unsigned int power_seg_sz)
+{
+	struct pblk *pblk = container_of(rb, struct pblk, rwb);
+	unsigned int init_entry = 0;
+	unsigned int alloc_order = power_size;
+	unsigned int max_order = MAX_ORDER - 1;
+	unsigned int order, iter;
+
+	down_write(&pblk_rb_lock);
+	rb->entries = rb_entry_base;
+	rb->seg_size = (1 << power_seg_sz);
+	rb->nr_entries = (1 << power_size);
+	rb->mem = rb->subm = rb->sync = rb->l2p_update = 0;
+	rb->sync_point = EMPTY_ENTRY;
+
+	spin_lock_init(&rb->w_lock);
+	spin_lock_init(&rb->s_lock);
+
+	INIT_LIST_HEAD(&rb->pages);
+
+	if (alloc_order >= max_order) {
+		order = max_order;
+		iter = (1 << (alloc_order - max_order));
+	} else {
+		order = alloc_order;
+		iter = 1;
+	}
+
+	do {
+		struct pblk_rb_entry *entry;
+		struct pblk_rb_pages *page_set;
+		void *kaddr;
+		unsigned long set_size;
+		int i;
+
+		page_set = kmalloc(sizeof(struct pblk_rb_pages), GFP_KERNEL);
+		if (!page_set) {
+			up_write(&pblk_rb_lock);
+			return -ENOMEM;
+		}
+
+		page_set->order = order;
+		page_set->pages = alloc_pages(GFP_KERNEL, order);
+		if (!page_set->pages) {
+			kfree(page_set);
+			pblk_rb_data_free(rb);
+			up_write(&pblk_rb_lock);
+			return -ENOMEM;
+		}
+		kaddr = page_address(page_set->pages);
+
+		entry = &rb->entries[init_entry];
+		entry->data = kaddr;
+		entry->cacheline = pblk_cacheline_to_addr(init_entry++);
+		entry->w_ctx.flags = PBLK_WRITABLE_ENTRY;
+
+		set_size = (1 << order);
+		for (i = 1; i < set_size; i++) {
+			entry = &rb->entries[init_entry];
+			entry->cacheline = pblk_cacheline_to_addr(init_entry++);
+			entry->data = kaddr + (i * rb->seg_size);
+			entry->w_ctx.flags = PBLK_WRITABLE_ENTRY;
+			bio_list_init(&entry->w_ctx.bios);
+		}
+
+		list_add_tail(&page_set->list, &rb->pages);
+		iter--;
+	} while (iter > 0);
+	up_write(&pblk_rb_lock);
+
+#ifdef CONFIG_NVM_DEBUG
+	atomic_set(&rb->inflight_sync_point, 0);
+#endif
+
+	/*
+	 * Initialize rate-limiter, which controls access to the write buffer
+	 * but user and GC I/O
+	 */
+	pblk_rl_init(&pblk->rl, rb->nr_entries);
+
+	return 0;
+}
+
+/*
+ * pblk_rb_calculate_size -- calculate the size of the write buffer
+ */
+unsigned int pblk_rb_calculate_size(unsigned int nr_entries)
+{
+	/* Alloc a write buffer that can at least fit 128 entries */
+	return (1 << max(get_count_order(nr_entries), 7));
+}
+
+void *pblk_rb_entries_ref(struct pblk_rb *rb)
+{
+	return rb->entries;
+}
+
+static void clean_wctx(struct pblk_w_ctx *w_ctx)
+{
+	int flags;
+
+try:
+	flags = READ_ONCE(w_ctx->flags);
+	if (!(flags & PBLK_SUBMITTED_ENTRY))
+		goto try;
+
+	/* Release flags on context. Protect from writes and reads */
+	smp_store_release(&w_ctx->flags, PBLK_WRITABLE_ENTRY);
+	pblk_ppa_set_empty(&w_ctx->ppa);
+}
+
+#define pblk_rb_ring_count(head, tail, size) CIRC_CNT(head, tail, size)
+#define pblk_rb_ring_space(rb, head, tail, size) \
+					(CIRC_SPACE(head, tail, size))
+
+/*
+ * Buffer space is calculated with respect to the back pointer signaling
+ * synchronized entries to the media.
+ */
+static unsigned int pblk_rb_space(struct pblk_rb *rb)
+{
+	unsigned int mem = READ_ONCE(rb->mem);
+	unsigned int sync = READ_ONCE(rb->sync);
+
+	return pblk_rb_ring_space(rb, mem, sync, rb->nr_entries);
+}
+
+/*
+ * Buffer count is calculated with respect to the submission entry signaling the
+ * entries that are available to send to the media
+ */
+unsigned int pblk_rb_read_count(struct pblk_rb *rb)
+{
+	unsigned int mem = READ_ONCE(rb->mem);
+	unsigned int subm = READ_ONCE(rb->subm);
+
+	return pblk_rb_ring_count(mem, subm, rb->nr_entries);
+}
+
+unsigned int pblk_rb_read_commit(struct pblk_rb *rb, unsigned int nr_entries)
+{
+	unsigned int subm;
+
+	subm = READ_ONCE(rb->subm);
+	/* Commit read means updating submission pointer */
+	smp_store_release(&rb->subm,
+				(subm + nr_entries) & (rb->nr_entries - 1));
+
+	return subm;
+}
+
+static int __pblk_rb_update_l2p(struct pblk_rb *rb, unsigned int *l2p_upd,
+				unsigned int to_update)
+{
+	struct pblk *pblk = container_of(rb, struct pblk, rwb);
+	struct pblk_line *line;
+	struct pblk_rb_entry *entry;
+	struct pblk_w_ctx *w_ctx;
+	unsigned int i;
+
+	for (i = 0; i < to_update; i++) {
+		entry = &rb->entries[*l2p_upd];
+		w_ctx = &entry->w_ctx;
+
+		pblk_update_map_dev(pblk, w_ctx->lba, w_ctx->ppa,
+							entry->cacheline);
+
+		line = &pblk->lines[pblk_tgt_ppa_to_line(w_ctx->ppa)];
+		kref_put(&line->ref, pblk_line_put);
+		clean_wctx(w_ctx);
+		*l2p_upd = (*l2p_upd + 1) & (rb->nr_entries - 1);
+	}
+
+	return 0;
+}
+
+/*
+ * When we move the l2p_update pointer, we update the l2p table - lookups will
+ * point to the physical address instead of to the cacheline in the write buffer
+ * from this moment on.
+ */
+static int pblk_rb_update_l2p(struct pblk_rb *rb, unsigned int nr_entries,
+			      unsigned int mem, unsigned int sync)
+{
+	unsigned int space, count;
+	int ret = 0;
+
+	lockdep_assert_held(&rb->w_lock);
+
+	/* Update l2p only as buffer entries are being overwritten */
+	space = pblk_rb_ring_space(rb, mem, rb->l2p_update, rb->nr_entries);
+	if (space > nr_entries)
+		goto out;
+
+	count = nr_entries - space;
+	/* l2p_update used exclusively under rb->w_lock */
+	ret = __pblk_rb_update_l2p(rb, &rb->l2p_update, count);
+
+out:
+	return ret;
+}
+
+/*
+ * Update the l2p entry for all sectors stored on the write buffer. This means
+ * that all future lookups to the l2p table will point to a device address, not
+ * to the cacheline in the write buffer.
+ */
+void pblk_rb_sync_l2p(struct pblk_rb *rb)
+{
+	unsigned int sync;
+	unsigned int to_update;
+
+	spin_lock(&rb->w_lock);
+
+	/* Protect from reads and writes */
+	sync = smp_load_acquire(&rb->sync);
+
+	to_update = pblk_rb_ring_count(sync, rb->l2p_update, rb->nr_entries);
+	__pblk_rb_update_l2p(rb, &rb->l2p_update, to_update);
+
+	spin_unlock(&rb->w_lock);
+}
+
+/*
+ * Write @nr_entries to ring buffer from @data buffer if there is enough space.
+ * Typically, 4KB data chunks coming from a bio will be copied to the ring
+ * buffer, thus the write will fail if not all incoming data can be copied.
+ *
+ */
+static void __pblk_rb_write_entry(struct pblk_rb *rb, void *data,
+				  struct pblk_w_ctx w_ctx,
+				  struct pblk_rb_entry *entry)
+{
+	memcpy(entry->data, data, rb->seg_size);
+
+	entry->w_ctx.lba = w_ctx.lba;
+	entry->w_ctx.ppa = w_ctx.ppa;
+}
+
+void pblk_rb_write_entry_user(struct pblk_rb *rb, void *data,
+			      struct pblk_w_ctx w_ctx, unsigned int ring_pos)
+{
+	struct pblk *pblk = container_of(rb, struct pblk, rwb);
+	struct pblk_rb_entry *entry;
+	int flags;
+
+	entry = &rb->entries[ring_pos];
+	flags = READ_ONCE(entry->w_ctx.flags);
+#ifdef CONFIG_NVM_DEBUG
+	/* Caller must guarantee that the entry is free */
+	BUG_ON(!(flags & PBLK_WRITABLE_ENTRY));
+#endif
+
+	__pblk_rb_write_entry(rb, data, w_ctx, entry);
+
+	pblk_update_map_cache(pblk, w_ctx.lba, entry->cacheline);
+	flags = w_ctx.flags | PBLK_WRITTEN_DATA;
+
+	/* Release flags on write context. Protect from writes */
+	smp_store_release(&entry->w_ctx.flags, flags);
+}
+
+void pblk_rb_write_entry_gc(struct pblk_rb *rb, void *data,
+			    struct pblk_w_ctx w_ctx, struct pblk_line *gc_line,
+			    unsigned int ring_pos)
+{
+	struct pblk *pblk = container_of(rb, struct pblk, rwb);
+	struct pblk_rb_entry *entry;
+	int flags;
+
+	entry = &rb->entries[ring_pos];
+	flags = READ_ONCE(entry->w_ctx.flags);
+#ifdef CONFIG_NVM_DEBUG
+	/* Caller must guarantee that the entry is free */
+	BUG_ON(!(flags & PBLK_WRITABLE_ENTRY));
+#endif
+
+	__pblk_rb_write_entry(rb, data, w_ctx, entry);
+
+	if (!pblk_update_map_gc(pblk, w_ctx.lba, entry->cacheline, gc_line))
+		entry->w_ctx.lba = ADDR_EMPTY;
+
+	flags = w_ctx.flags | PBLK_WRITTEN_DATA;
+
+	/* Release flags on write context. Protect from writes */
+	smp_store_release(&entry->w_ctx.flags, flags);
+}
+
+static int pblk_rb_sync_point_set(struct pblk_rb *rb, struct bio *bio,
+				  unsigned int pos)
+{
+	struct pblk_rb_entry *entry;
+	unsigned int subm, sync_point;
+	int flags;
+
+	subm = READ_ONCE(rb->subm);
+
+#ifdef CONFIG_NVM_DEBUG
+	atomic_inc(&rb->inflight_sync_point);
+#endif
+
+	if (pos == subm)
+		return 0;
+
+	sync_point = (pos == 0) ? (rb->nr_entries - 1) : (pos - 1);
+	entry = &rb->entries[sync_point];
+
+	flags = READ_ONCE(entry->w_ctx.flags);
+	flags |= PBLK_FLUSH_ENTRY;
+
+	/* Release flags on context. Protect from writes */
+	smp_store_release(&entry->w_ctx.flags, flags);
+
+	/* Protect syncs */
+	smp_store_release(&rb->sync_point, sync_point);
+
+	spin_lock_irq(&rb->s_lock);
+	bio_list_add(&entry->w_ctx.bios, bio);
+	spin_unlock_irq(&rb->s_lock);
+
+	return 1;
+}
+
+static int __pblk_rb_may_write(struct pblk_rb *rb, unsigned int nr_entries,
+			       unsigned int *pos)
+{
+	unsigned int mem;
+	unsigned int sync;
+
+	sync = READ_ONCE(rb->sync);
+	mem = READ_ONCE(rb->mem);
+
+	if (pblk_rb_ring_space(rb, mem, sync, rb->nr_entries) < nr_entries)
+		return 0;
+
+	if (pblk_rb_update_l2p(rb, nr_entries, mem, sync))
+		return 0;
+
+	*pos = mem;
+
+	return 1;
+}
+
+static int pblk_rb_may_write(struct pblk_rb *rb, unsigned int nr_entries,
+			     unsigned int *pos)
+{
+	if (!__pblk_rb_may_write(rb, nr_entries, pos))
+		return 0;
+
+	/* Protect from read count */
+	smp_store_release(&rb->mem, (*pos + nr_entries) & (rb->nr_entries - 1));
+	return 1;
+}
+
+static int pblk_rb_may_write_flush(struct pblk_rb *rb, unsigned int nr_entries,
+				   unsigned int *pos, struct bio *bio,
+				   int *io_ret)
+{
+	unsigned int mem;
+
+	if (!__pblk_rb_may_write(rb, nr_entries, pos))
+		return 0;
+
+	mem = (*pos + nr_entries) & (rb->nr_entries - 1);
+	*io_ret = NVM_IO_DONE;
+
+	if (bio->bi_opf & REQ_PREFLUSH) {
+		struct pblk *pblk = container_of(rb, struct pblk, rwb);
+
+#ifdef CONFIG_NVM_DEBUG
+		atomic_long_inc(&pblk->nr_flush);
+#endif
+		if (pblk_rb_sync_point_set(&pblk->rwb, bio, mem))
+			*io_ret = NVM_IO_OK;
+	}
+
+	/* Protect from read count */
+	smp_store_release(&rb->mem, mem);
+	return 1;
+}
+
+/*
+ * Atomically check that (i) there is space on the write buffer for the
+ * incoming I/O, and (ii) the current I/O type has enough budget in the write
+ * buffer (rate-limiter).
+ */
+int pblk_rb_may_write_user(struct pblk_rb *rb, struct bio *bio,
+			   unsigned int nr_entries, unsigned int *pos)
+{
+	struct pblk *pblk = container_of(rb, struct pblk, rwb);
+	int flush_done;
+
+	spin_lock(&rb->w_lock);
+	if (!pblk_rl_user_may_insert(&pblk->rl, nr_entries)) {
+		spin_unlock(&rb->w_lock);
+		return NVM_IO_REQUEUE;
+	}
+
+	if (!pblk_rb_may_write_flush(rb, nr_entries, pos, bio, &flush_done)) {
+		spin_unlock(&rb->w_lock);
+		return NVM_IO_REQUEUE;
+	}
+
+	pblk_rl_user_in(&pblk->rl, nr_entries);
+	spin_unlock(&rb->w_lock);
+
+	return flush_done;
+}
+
+/*
+ * Look at pblk_rb_may_write_user comment
+ */
+int pblk_rb_may_write_gc(struct pblk_rb *rb, unsigned int nr_entries,
+			 unsigned int *pos)
+{
+	struct pblk *pblk = container_of(rb, struct pblk, rwb);
+
+	spin_lock(&rb->w_lock);
+	if (!pblk_rl_gc_may_insert(&pblk->rl, nr_entries)) {
+		spin_unlock(&rb->w_lock);
+		return 0;
+	}
+
+	if (!pblk_rb_may_write(rb, nr_entries, pos)) {
+		spin_unlock(&rb->w_lock);
+		return 0;
+	}
+
+	pblk_rl_gc_in(&pblk->rl, nr_entries);
+	spin_unlock(&rb->w_lock);
+
+	return 1;
+}
+
+/*
+ * The caller of this function must ensure that the backpointer will not
+ * overwrite the entries passed on the list.
+ */
+unsigned int pblk_rb_read_to_bio_list(struct pblk_rb *rb, struct bio *bio,
+				      struct list_head *list,
+				      unsigned int max)
+{
+	struct pblk_rb_entry *entry, *tentry;
+	struct page *page;
+	unsigned int read = 0;
+	int ret;
+
+	list_for_each_entry_safe(entry, tentry, list, index) {
+		if (read > max) {
+			pr_err("pblk: too many entries on list\n");
+			goto out;
+		}
+
+		page = virt_to_page(entry->data);
+		if (!page) {
+			pr_err("pblk: could not allocate write bio page\n");
+			goto out;
+		}
+
+		ret = bio_add_page(bio, page, rb->seg_size, 0);
+		if (ret != rb->seg_size) {
+			pr_err("pblk: could not add page to write bio\n");
+			goto out;
+		}
+
+		list_del(&entry->index);
+		read++;
+	}
+
+out:
+	return read;
+}
+
+/*
+ * Read available entries on rb and add them to the given bio. To avoid a memory
+ * copy, a page reference to the write buffer is used to be added to the bio.
+ *
+ * This function is used by the write thread to form the write bio that will
+ * persist data on the write buffer to the media.
+ */
+unsigned int pblk_rb_read_to_bio(struct pblk_rb *rb, struct bio *bio,
+				 struct pblk_c_ctx *c_ctx,
+				 unsigned int pos,
+				 unsigned int nr_entries,
+				 unsigned int count)
+{
+	struct pblk *pblk = container_of(rb, struct pblk, rwb);
+	struct pblk_rb_entry *entry;
+	struct page *page;
+	unsigned int pad = 0, read = 0, to_read = nr_entries;
+	unsigned int user_io = 0, gc_io = 0;
+	unsigned int i;
+	int flags;
+	int ret;
+
+	if (count < nr_entries) {
+		pad = nr_entries - count;
+		to_read = count;
+	}
+
+	c_ctx->sentry = pos;
+	c_ctx->nr_valid = to_read;
+	c_ctx->nr_padded = pad;
+
+	for (i = 0; i < to_read; i++) {
+		entry = &rb->entries[pos];
+
+		/* A write has been allowed into the buffer, but data is still
+		 * being copied to it. It is ok to busy wait.
+		 */
+try:
+		flags = READ_ONCE(entry->w_ctx.flags);
+		if (!(flags & PBLK_WRITTEN_DATA))
+			goto try;
+
+		if (flags & PBLK_IOTYPE_USER)
+			user_io++;
+		else if (flags & PBLK_IOTYPE_GC)
+			gc_io++;
+		else
+			WARN(1, "pblk: unknown IO type\n");
+
+		page = virt_to_page(entry->data);
+		if (!page) {
+			pr_err("pblk: could not allocate write bio page\n");
+			flags &= ~PBLK_WRITTEN_DATA;
+			flags |= PBLK_SUBMITTED_ENTRY;
+			/* Release flags on context. Protect from writes */
+			smp_store_release(&entry->w_ctx.flags, flags);
+			goto out;
+		}
+
+		ret = bio_add_page(bio, page, rb->seg_size, 0);
+		if (ret != rb->seg_size) {
+			pr_err("pblk: could not add page to write bio\n");
+			flags &= ~PBLK_WRITTEN_DATA;
+			flags |= PBLK_SUBMITTED_ENTRY;
+			/* Release flags on context. Protect from writes */
+			smp_store_release(&entry->w_ctx.flags, flags);
+			goto out;
+		}
+
+		if (flags & PBLK_FLUSH_ENTRY) {
+			unsigned int sync_point;
+
+			sync_point = READ_ONCE(rb->sync_point);
+			if (sync_point == pos) {
+				/* Protect syncs */
+				smp_store_release(&rb->sync_point, EMPTY_ENTRY);
+			}
+
+			flags &= ~PBLK_FLUSH_ENTRY;
+#ifdef CONFIG_NVM_DEBUG
+			atomic_dec(&rb->inflight_sync_point);
+#endif
+		}
+
+		flags &= ~PBLK_WRITTEN_DATA;
+		flags |= PBLK_SUBMITTED_ENTRY;
+
+		/* Release flags on context. Protect from writes */
+		smp_store_release(&entry->w_ctx.flags, flags);
+
+		pos = (pos + 1) & (rb->nr_entries - 1);
+	}
+
+	read = to_read;
+	pblk_rl_out(&pblk->rl, user_io, gc_io);
+#ifdef CONFIG_NVM_DEBUG
+	atomic_long_add(pad, &((struct pblk *)
+			(container_of(rb, struct pblk, rwb)))->padded_writes);
+#endif
+out:
+	return read;
+}
+
+/*
+ * Copy to bio only if the lba matches the one on the given cache entry.
+ * Otherwise, it means that the entry has been overwritten, and the bio should
+ * be directed to disk.
+ */
+int pblk_rb_copy_to_bio(struct pblk_rb *rb, struct bio *bio, sector_t lba,
+			u64 pos, int bio_iter)
+{
+	struct pblk_rb_entry *entry;
+	struct pblk_w_ctx *w_ctx;
+	void *data;
+	int flags;
+	int ret = 1;
+
+	spin_lock(&rb->w_lock);
+
+#ifdef CONFIG_NVM_DEBUG
+	/* Caller must ensure that the access will not cause an overflow */
+	BUG_ON(pos >= rb->nr_entries);
+#endif
+	entry = &rb->entries[pos];
+	w_ctx = &entry->w_ctx;
+	flags = READ_ONCE(w_ctx->flags);
+
+	/* Check if the entry has been overwritten or is scheduled to be */
+	if (w_ctx->lba != lba || flags & PBLK_WRITABLE_ENTRY) {
+		ret = 0;
+		goto out;
+	}
+
+	/* Only advance the bio if it hasn't been advanced already. If advanced,
+	 * this bio is at least a partial bio (i.e., it has partially been
+	 * filled with data from the cache). If part of the data resides on the
+	 * media, we will read later on
+	 */
+	if (unlikely(!bio->bi_iter.bi_idx))
+		bio_advance(bio, bio_iter * PBLK_EXPOSED_PAGE_SIZE);
+
+	data = bio_data(bio);
+	memcpy(data, entry->data, rb->seg_size);
+
+out:
+	spin_unlock(&rb->w_lock);
+	return ret;
+}
+
+struct pblk_w_ctx *pblk_rb_w_ctx(struct pblk_rb *rb, unsigned int pos)
+{
+	unsigned int entry = pos & (rb->nr_entries - 1);
+
+	return &rb->entries[entry].w_ctx;
+}
+
+unsigned int pblk_rb_sync_init(struct pblk_rb *rb, unsigned long *flags)
+	__acquires(&rb->s_lock)
+{
+	if (flags)
+		spin_lock_irqsave(&rb->s_lock, *flags);
+	else
+		spin_lock_irq(&rb->s_lock);
+
+	return rb->sync;
+}
+
+void pblk_rb_sync_end(struct pblk_rb *rb, unsigned long *flags)
+	__releases(&rb->s_lock)
+{
+	lockdep_assert_held(&rb->s_lock);
+
+	if (flags)
+		spin_unlock_irqrestore(&rb->s_lock, *flags);
+	else
+		spin_unlock_irq(&rb->s_lock);
+}
+
+unsigned int pblk_rb_sync_advance(struct pblk_rb *rb, unsigned int nr_entries)
+{
+	unsigned int sync;
+	unsigned int i;
+
+	lockdep_assert_held(&rb->s_lock);
+
+	sync = READ_ONCE(rb->sync);
+
+	for (i = 0; i < nr_entries; i++)
+		sync = (sync + 1) & (rb->nr_entries - 1);
+
+	/* Protect from counts */
+	smp_store_release(&rb->sync, sync);
+
+	return sync;
+}
+
+unsigned int pblk_rb_sync_point_count(struct pblk_rb *rb)
+{
+	unsigned int subm, sync_point;
+	unsigned int count;
+
+	/* Protect syncs */
+	sync_point = smp_load_acquire(&rb->sync_point);
+	if (sync_point == EMPTY_ENTRY)
+		return 0;
+
+	subm = READ_ONCE(rb->subm);
+
+	/* The sync point itself counts as a sector to sync */
+	count = pblk_rb_ring_count(sync_point, subm, rb->nr_entries) + 1;
+
+	return count;
+}
+
+/*
+ * Scan from the current position of the sync pointer to find the entry that
+ * corresponds to the given ppa. This is necessary since write requests can be
+ * completed out of order. The assumption is that the ppa is close to the sync
+ * pointer thus the search will not take long.
+ *
+ * The caller of this function must guarantee that the sync pointer will no
+ * reach the entry while it is using the metadata associated with it. With this
+ * assumption in mind, there is no need to take the sync lock.
+ */
+struct pblk_rb_entry *pblk_rb_sync_scan_entry(struct pblk_rb *rb,
+					      struct ppa_addr *ppa)
+{
+	unsigned int sync, subm, count;
+	unsigned int i;
+
+	sync = READ_ONCE(rb->sync);
+	subm = READ_ONCE(rb->subm);
+	count = pblk_rb_ring_count(subm, sync, rb->nr_entries);
+
+	for (i = 0; i < count; i++)
+		sync = (sync + 1) & (rb->nr_entries - 1);
+
+	return NULL;
+}
+
+int pblk_rb_tear_down_check(struct pblk_rb *rb)
+{
+	struct pblk_rb_entry *entry;
+	int i;
+	int ret = 0;
+
+	spin_lock(&rb->w_lock);
+	spin_lock_irq(&rb->s_lock);
+
+	if ((rb->mem == rb->subm) && (rb->subm == rb->sync) &&
+				(rb->sync == rb->l2p_update) &&
+				(rb->sync_point == EMPTY_ENTRY)) {
+		goto out;
+	}
+
+	if (!rb->entries) {
+		ret = 1;
+		goto out;
+	}
+
+	for (i = 0; i < rb->nr_entries; i++) {
+		entry = &rb->entries[i];
+
+		if (!entry->data) {
+			ret = 1;
+			goto out;
+		}
+	}
+
+out:
+	spin_unlock(&rb->w_lock);
+	spin_unlock_irq(&rb->s_lock);
+
+	return ret;
+}
+
+unsigned int pblk_rb_wrap_pos(struct pblk_rb *rb, unsigned int pos)
+{
+	return (pos & (rb->nr_entries - 1));
+}
+
+int pblk_rb_pos_oob(struct pblk_rb *rb, u64 pos)
+{
+	return (pos >= rb->nr_entries);
+}
+
+ssize_t pblk_rb_sysfs(struct pblk_rb *rb, char *buf)
+{
+	struct pblk *pblk = container_of(rb, struct pblk, rwb);
+	struct pblk_c_ctx *c;
+	ssize_t offset;
+	int queued_entries = 0;
+
+	spin_lock_irq(&rb->s_lock);
+	list_for_each_entry(c, &pblk->compl_list, list)
+		queued_entries++;
+	spin_unlock_irq(&rb->s_lock);
+
+	if (rb->sync_point != EMPTY_ENTRY)
+		offset = scnprintf(buf, PAGE_SIZE,
+			"%u\t%u\t%u\t%u\t%u\t%u\t%u - %u/%u/%u - %d\n",
+			rb->nr_entries,
+			rb->mem,
+			rb->subm,
+			rb->sync,
+			rb->l2p_update,
+#ifdef CONFIG_NVM_DEBUG
+			atomic_read(&rb->inflight_sync_point),
+#else
+			0,
+#endif
+			rb->sync_point,
+			pblk_rb_read_count(rb),
+			pblk_rb_space(rb),
+			pblk_rb_sync_point_count(rb),
+			queued_entries);
+	else
+		offset = scnprintf(buf, PAGE_SIZE,
+			"%u\t%u\t%u\t%u\t%u\t%u\tNULL - %u/%u/%u - %d\n",
+			rb->nr_entries,
+			rb->mem,
+			rb->subm,
+			rb->sync,
+			rb->l2p_update,
+#ifdef CONFIG_NVM_DEBUG
+			atomic_read(&rb->inflight_sync_point),
+#else
+			0,
+#endif
+			pblk_rb_read_count(rb),
+			pblk_rb_space(rb),
+			pblk_rb_sync_point_count(rb),
+			queued_entries);
+
+	return offset;
+}

drivers/lightnvm/pblk-read.c

+/*
+ * Copyright (C) 2016 CNEX Labs
+ * Initial release: Javier Gonzalez <javier@cnexlabs.com>
+ *                  Matias Bjorling <matias@cnexlabs.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * pblk-read.c - pblk's read path
+ */
+
+#include "pblk.h"
+
+/*
+ * There is no guarantee that the value read from cache has not been updated and
+ * resides at another location in the cache. We guarantee though that if the
+ * value is read from the cache, it belongs to the mapped lba. In order to
+ * guarantee and order between writes and reads are ordered, a flush must be
+ * issued.
+ */
+static int pblk_read_from_cache(struct pblk *pblk, struct bio *bio,
+				sector_t lba, struct ppa_addr ppa,
+				int bio_iter)
+{
+#ifdef CONFIG_NVM_DEBUG
+	/* Callers must ensure that the ppa points to a cache address */
+	BUG_ON(pblk_ppa_empty(ppa));
+	BUG_ON(!pblk_addr_in_cache(ppa));
+#endif
+
+	return pblk_rb_copy_to_bio(&pblk->rwb, bio, lba,
+					pblk_addr_to_cacheline(ppa), bio_iter);
+}
+
+static void pblk_read_ppalist_rq(struct pblk *pblk, struct nvm_rq *rqd,
+				 unsigned long *read_bitmap)
+{
+	struct bio *bio = rqd->bio;
+	struct ppa_addr ppas[PBLK_MAX_REQ_ADDRS];
+	sector_t blba = pblk_get_lba(bio);
+	int nr_secs = rqd->nr_ppas;
+	int advanced_bio = 0;
+	int i, j = 0;
+
+	/* logic error: lba out-of-bounds. Ignore read request */
+	if (!(blba + nr_secs < pblk->rl.nr_secs)) {
+		WARN_ON("pblk: read lbas out of bounds\n");
+		return;
+	}
+
+	pblk_lookup_l2p_seq(pblk, ppas, blba, nr_secs);
+
+	for (i = 0; i < nr_secs; i++) {
+		struct ppa_addr p = ppas[i];
+		sector_t lba = blba + i;
+
+retry:
+		if (pblk_ppa_empty(p)) {
+			WARN_ON(test_and_set_bit(i, read_bitmap));
+			continue;
+		}
+
+		/* Try to read from write buffer. The address is later checked
+		 * on the write buffer to prevent retrieving overwritten data.
+		 */
+		if (pblk_addr_in_cache(p)) {
+			if (!pblk_read_from_cache(pblk, bio, lba, p, i)) {
+				pblk_lookup_l2p_seq(pblk, &p, lba, 1);
+				goto retry;
+			}
+			WARN_ON(test_and_set_bit(i, read_bitmap));
+			advanced_bio = 1;
+		} else {
+			/* Read from media non-cached sectors */
+			rqd->ppa_list[j++] = p;
+		}
+
+		if (advanced_bio)
+			bio_advance(bio, PBLK_EXPOSED_PAGE_SIZE);
+	}
+
+#ifdef CONFIG_NVM_DEBUG
+	atomic_long_add(nr_secs, &pblk->inflight_reads);
+#endif
+}
+
+static int pblk_submit_read_io(struct pblk *pblk, struct nvm_rq *rqd)
+{
+	int err;
+
+	rqd->flags = pblk_set_read_mode(pblk);
+
+	err = pblk_submit_io(pblk, rqd);
+	if (err)
+		return NVM_IO_ERR;
+
+	return NVM_IO_OK;
+}
+
+static void pblk_end_io_read(struct nvm_rq *rqd)
+{
+	struct pblk *pblk = rqd->private;
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct pblk_r_ctx *r_ctx = nvm_rq_to_pdu(rqd);
+	struct bio *bio = rqd->bio;
+
+	if (rqd->error)
+		pblk_log_read_err(pblk, rqd);
+#ifdef CONFIG_NVM_DEBUG
+	else
+		WARN_ONCE(bio->bi_error, "pblk: corrupted read error\n");
+#endif
+
+	if (rqd->nr_ppas > 1)
+		nvm_dev_dma_free(dev->parent, rqd->ppa_list, rqd->dma_ppa_list);
+
+	bio_put(bio);
+	if (r_ctx->orig_bio) {
+#ifdef CONFIG_NVM_DEBUG
+		WARN_ONCE(r_ctx->orig_bio->bi_error,
+						"pblk: corrupted read bio\n");
+#endif
+		bio_endio(r_ctx->orig_bio);
+		bio_put(r_ctx->orig_bio);
+	}
+
+#ifdef CONFIG_NVM_DEBUG
+	atomic_long_add(rqd->nr_ppas, &pblk->sync_reads);
+	atomic_long_sub(rqd->nr_ppas, &pblk->inflight_reads);
+#endif
+
+	pblk_free_rqd(pblk, rqd, READ);
+}
+
+static int pblk_fill_partial_read_bio(struct pblk *pblk, struct nvm_rq *rqd,
+				      unsigned int bio_init_idx,
+				      unsigned long *read_bitmap)
+{
+	struct bio *new_bio, *bio = rqd->bio;
+	struct bio_vec src_bv, dst_bv;
+	void *ppa_ptr = NULL;
+	void *src_p, *dst_p;
+	dma_addr_t dma_ppa_list = 0;
+	int nr_secs = rqd->nr_ppas;
+	int nr_holes = nr_secs - bitmap_weight(read_bitmap, nr_secs);
+	int i, ret, hole;
+	DECLARE_COMPLETION_ONSTACK(wait);
+
+	new_bio = bio_alloc(GFP_KERNEL, nr_holes);
+	if (!new_bio) {
+		pr_err("pblk: could not alloc read bio\n");
+		return NVM_IO_ERR;
+	}
+
+	if (pblk_bio_add_pages(pblk, new_bio, GFP_KERNEL, nr_holes))
+		goto err;
+
+	if (nr_holes != new_bio->bi_vcnt) {
+		pr_err("pblk: malformed bio\n");
+		goto err;
+	}
+
+	new_bio->bi_iter.bi_sector = 0; /* internal bio */
+	bio_set_op_attrs(new_bio, REQ_OP_READ, 0);
+	new_bio->bi_private = &wait;
+	new_bio->bi_end_io = pblk_end_bio_sync;
+
+	rqd->bio = new_bio;
+	rqd->nr_ppas = nr_holes;
+	rqd->end_io = NULL;
+
+	if (unlikely(nr_secs > 1 && nr_holes == 1)) {
+		ppa_ptr = rqd->ppa_list;
+		dma_ppa_list = rqd->dma_ppa_list;
+		rqd->ppa_addr = rqd->ppa_list[0];
+	}
+
+	ret = pblk_submit_read_io(pblk, rqd);
+	if (ret) {
+		bio_put(rqd->bio);
+		pr_err("pblk: read IO submission failed\n");
+		goto err;
+	}
+
+	if (!wait_for_completion_io_timeout(&wait,
+				msecs_to_jiffies(PBLK_COMMAND_TIMEOUT_MS))) {
+		pr_err("pblk: partial read I/O timed out\n");
+	}
+
+	if (rqd->error) {
+		atomic_long_inc(&pblk->read_failed);
+#ifdef CONFIG_NVM_DEBUG
+		pblk_print_failed_rqd(pblk, rqd, rqd->error);
+#endif
+	}
+
+	if (unlikely(nr_secs > 1 && nr_holes == 1)) {
+		rqd->ppa_list = ppa_ptr;
+		rqd->dma_ppa_list = dma_ppa_list;
+	}
+
+	/* Fill the holes in the original bio */
+	i = 0;
+	hole = find_first_zero_bit(read_bitmap, nr_secs);
+	do {
+		src_bv = new_bio->bi_io_vec[i++];
+		dst_bv = bio->bi_io_vec[bio_init_idx + hole];
+
+		src_p = kmap_atomic(src_bv.bv_page);
+		dst_p = kmap_atomic(dst_bv.bv_page);
+
+		memcpy(dst_p + dst_bv.bv_offset,
+			src_p + src_bv.bv_offset,
+			PBLK_EXPOSED_PAGE_SIZE);
+
+		kunmap_atomic(src_p);
+		kunmap_atomic(dst_p);
+
+		mempool_free(src_bv.bv_page, pblk->page_pool);
+
+		hole = find_next_zero_bit(read_bitmap, nr_secs, hole + 1);
+	} while (hole < nr_secs);
+
+	bio_put(new_bio);
+
+	/* Complete the original bio and associated request */
+	rqd->bio = bio;
+	rqd->nr_ppas = nr_secs;
+	rqd->private = pblk;
+
+	bio_endio(bio);
+	pblk_end_io_read(rqd);
+	return NVM_IO_OK;
+
+err:
+	/* Free allocated pages in new bio */
+	pblk_bio_free_pages(pblk, bio, 0, new_bio->bi_vcnt);
+	rqd->private = pblk;
+	pblk_end_io_read(rqd);
+	return NVM_IO_ERR;
+}
+
+static void pblk_read_rq(struct pblk *pblk, struct nvm_rq *rqd,
+			 unsigned long *read_bitmap)
+{
+	struct bio *bio = rqd->bio;
+	struct ppa_addr ppa;
+	sector_t lba = pblk_get_lba(bio);
+
+	/* logic error: lba out-of-bounds. Ignore read request */
+	if (!(lba < pblk->rl.nr_secs)) {
+		WARN_ON("pblk: read lba out of bounds\n");
+		return;
+	}
+
+	pblk_lookup_l2p_seq(pblk, &ppa, lba, 1);
+
+#ifdef CONFIG_NVM_DEBUG
+	atomic_long_inc(&pblk->inflight_reads);
+#endif
+
+retry:
+	if (pblk_ppa_empty(ppa)) {
+		WARN_ON(test_and_set_bit(0, read_bitmap));
+		return;
+	}
+
+	/* Try to read from write buffer. The address is later checked on the
+	 * write buffer to prevent retrieving overwritten data.
+	 */
+	if (pblk_addr_in_cache(ppa)) {
+		if (!pblk_read_from_cache(pblk, bio, lba, ppa, 0)) {
+			pblk_lookup_l2p_seq(pblk, &ppa, lba, 1);
+			goto retry;
+		}
+		WARN_ON(test_and_set_bit(0, read_bitmap));
+	} else {
+		rqd->ppa_addr = ppa;
+	}
+}
+
+int pblk_submit_read(struct pblk *pblk, struct bio *bio)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	int nr_secs = pblk_get_secs(bio);
+	struct nvm_rq *rqd;
+	unsigned long read_bitmap; /* Max 64 ppas per request */
+	unsigned int bio_init_idx;
+	int ret = NVM_IO_ERR;
+
+	if (nr_secs > PBLK_MAX_REQ_ADDRS)
+		return NVM_IO_ERR;
+
+	bitmap_zero(&read_bitmap, nr_secs);
+
+	rqd = pblk_alloc_rqd(pblk, READ);
+	if (IS_ERR(rqd)) {
+		pr_err_ratelimited("pblk: not able to alloc rqd");
+		return NVM_IO_ERR;
+	}
+
+	rqd->opcode = NVM_OP_PREAD;
+	rqd->bio = bio;
+	rqd->nr_ppas = nr_secs;
+	rqd->private = pblk;
+	rqd->end_io = pblk_end_io_read;
+
+	/* Save the index for this bio's start. This is needed in case
+	 * we need to fill a partial read.
+	 */
+	bio_init_idx = pblk_get_bi_idx(bio);
+
+	if (nr_secs > 1) {
+		rqd->ppa_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
+						&rqd->dma_ppa_list);
+		if (!rqd->ppa_list) {
+			pr_err("pblk: not able to allocate ppa list\n");
+			goto fail_rqd_free;
+		}
+
+		pblk_read_ppalist_rq(pblk, rqd, &read_bitmap);
+	} else {
+		pblk_read_rq(pblk, rqd, &read_bitmap);
+	}
+
+	bio_get(bio);
+	if (bitmap_full(&read_bitmap, nr_secs)) {
+		bio_endio(bio);
+		pblk_end_io_read(rqd);
+		return NVM_IO_OK;
+	}
+
+	/* All sectors are to be read from the device */
+	if (bitmap_empty(&read_bitmap, rqd->nr_ppas)) {
+		struct bio *int_bio = NULL;
+		struct pblk_r_ctx *r_ctx = nvm_rq_to_pdu(rqd);
+
+		/* Clone read bio to deal with read errors internally */
+		int_bio = bio_clone_bioset(bio, GFP_KERNEL, fs_bio_set);
+		if (!int_bio) {
+			pr_err("pblk: could not clone read bio\n");
+			return NVM_IO_ERR;
+		}
+
+		rqd->bio = int_bio;
+		r_ctx->orig_bio = bio;
+
+		ret = pblk_submit_read_io(pblk, rqd);
+		if (ret) {
+			pr_err("pblk: read IO submission failed\n");
+			if (int_bio)
+				bio_put(int_bio);
+			return ret;
+		}
+
+		return NVM_IO_OK;
+	}
+
+	/* The read bio request could be partially filled by the write buffer,
+	 * but there are some holes that need to be read from the drive.
+	 */
+	ret = pblk_fill_partial_read_bio(pblk, rqd, bio_init_idx, &read_bitmap);
+	if (ret) {
+		pr_err("pblk: failed to perform partial read\n");
+		return ret;
+	}
+
+	return NVM_IO_OK;
+
+fail_rqd_free:
+	pblk_free_rqd(pblk, rqd, READ);
+	return ret;
+}
+
+static int read_ppalist_rq_gc(struct pblk *pblk, struct nvm_rq *rqd,
+			      struct pblk_line *line, u64 *lba_list,
+			      unsigned int nr_secs)
+{
+	struct ppa_addr ppas[PBLK_MAX_REQ_ADDRS];
+	int valid_secs = 0;
+	int i;
+
+	pblk_lookup_l2p_rand(pblk, ppas, lba_list, nr_secs);
+
+	for (i = 0; i < nr_secs; i++) {
+		if (pblk_addr_in_cache(ppas[i]) || ppas[i].g.blk != line->id ||
+						pblk_ppa_empty(ppas[i])) {
+			lba_list[i] = ADDR_EMPTY;
+			continue;
+		}
+
+		rqd->ppa_list[valid_secs++] = ppas[i];
+	}
+
+#ifdef CONFIG_NVM_DEBUG
+	atomic_long_add(valid_secs, &pblk->inflight_reads);
+#endif
+	return valid_secs;
+}
+
+static int read_rq_gc(struct pblk *pblk, struct nvm_rq *rqd,
+		      struct pblk_line *line, sector_t lba)
+{
+	struct ppa_addr ppa;
+	int valid_secs = 0;
+
+	/* logic error: lba out-of-bounds */
+	if (!(lba < pblk->rl.nr_secs)) {
+		WARN_ON("pblk: read lba out of bounds\n");
+		goto out;
+	}
+
+	if (lba == ADDR_EMPTY)
+		goto out;
+
+	spin_lock(&pblk->trans_lock);
+	ppa = pblk_trans_map_get(pblk, lba);
+	spin_unlock(&pblk->trans_lock);
+
+	/* Ignore updated values until the moment */
+	if (pblk_addr_in_cache(ppa) || ppa.g.blk != line->id ||
+							pblk_ppa_empty(ppa))
+		goto out;
+
+	rqd->ppa_addr = ppa;
+	valid_secs = 1;
+
+#ifdef CONFIG_NVM_DEBUG
+	atomic_long_inc(&pblk->inflight_reads);
+#endif
+
+out:
+	return valid_secs;
+}
+
+int pblk_submit_read_gc(struct pblk *pblk, u64 *lba_list, void *data,
+			unsigned int nr_secs, unsigned int *secs_to_gc,
+			struct pblk_line *line)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct request_queue *q = dev->q;
+	struct bio *bio;
+	struct nvm_rq rqd;
+	int ret, data_len;
+	DECLARE_COMPLETION_ONSTACK(wait);
+
+	memset(&rqd, 0, sizeof(struct nvm_rq));
+
+	if (nr_secs > 1) {
+		rqd.ppa_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
+							&rqd.dma_ppa_list);
+		if (!rqd.ppa_list)
+			return NVM_IO_ERR;
+
+		*secs_to_gc = read_ppalist_rq_gc(pblk, &rqd, line, lba_list,
+								nr_secs);
+		if (*secs_to_gc == 1) {
+			struct ppa_addr ppa;
+
+			ppa = rqd.ppa_list[0];
+			nvm_dev_dma_free(dev->parent, rqd.ppa_list,
+							rqd.dma_ppa_list);
+			rqd.ppa_addr = ppa;
+		}
+	} else {
+		*secs_to_gc = read_rq_gc(pblk, &rqd, line, lba_list[0]);
+	}
+
+	if (!(*secs_to_gc))
+		goto out;
+
+	data_len = (*secs_to_gc) * geo->sec_size;
+	bio = bio_map_kern(q, data, data_len, GFP_KERNEL);
+	if (IS_ERR(bio)) {
+		pr_err("pblk: could not allocate GC bio (%lu)\n", PTR_ERR(bio));
+		goto err_free_dma;
+	}
+
+	bio->bi_iter.bi_sector = 0; /* internal bio */
+	bio_set_op_attrs(bio, REQ_OP_READ, 0);
+
+	rqd.opcode = NVM_OP_PREAD;
+	rqd.end_io = pblk_end_io_sync;
+	rqd.private = &wait;
+	rqd.nr_ppas = *secs_to_gc;
+	rqd.bio = bio;
+
+	ret = pblk_submit_read_io(pblk, &rqd);
+	if (ret) {
+		bio_endio(bio);
+		pr_err("pblk: GC read request failed\n");
+		goto err_free_dma;
+	}
+
+	if (!wait_for_completion_io_timeout(&wait,
+				msecs_to_jiffies(PBLK_COMMAND_TIMEOUT_MS))) {
+		pr_err("pblk: GC read I/O timed out\n");
+	}
+
+	if (rqd.error) {
+		atomic_long_inc(&pblk->read_failed_gc);
+#ifdef CONFIG_NVM_DEBUG
+		pblk_print_failed_rqd(pblk, &rqd, rqd.error);
+#endif
+	}
+
+#ifdef CONFIG_NVM_DEBUG
+	atomic_long_add(*secs_to_gc, &pblk->sync_reads);
+	atomic_long_add(*secs_to_gc, &pblk->recov_gc_reads);
+	atomic_long_sub(*secs_to_gc, &pblk->inflight_reads);
+#endif
+
+out:
+	if (rqd.nr_ppas > 1)
+		nvm_dev_dma_free(dev->parent, rqd.ppa_list, rqd.dma_ppa_list);
+	return NVM_IO_OK;
+
+err_free_dma:
+	if (rqd.nr_ppas > 1)
+		nvm_dev_dma_free(dev->parent, rqd.ppa_list, rqd.dma_ppa_list);
+	return NVM_IO_ERR;
+}

drivers/lightnvm/pblk-recovery.c

+/*
+ * Copyright (C) 2016 CNEX Labs
+ * Initial: Javier Gonzalez <javier@cnexlabs.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * pblk-recovery.c - pblk's recovery path
+ */
+
+#include "pblk.h"
+
+void pblk_submit_rec(struct work_struct *work)
+{
+	struct pblk_rec_ctx *recovery =
+			container_of(work, struct pblk_rec_ctx, ws_rec);
+	struct pblk *pblk = recovery->pblk;
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_rq *rqd = recovery->rqd;
+	struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
+	int max_secs = nvm_max_phys_sects(dev);
+	struct bio *bio;
+	unsigned int nr_rec_secs;
+	unsigned int pgs_read;
+	int ret;
+
+	nr_rec_secs = bitmap_weight((unsigned long int *)&rqd->ppa_status,
+								max_secs);
+
+	bio = bio_alloc(GFP_KERNEL, nr_rec_secs);
+	if (!bio) {
+		pr_err("pblk: not able to create recovery bio\n");
+		return;
+	}
+
+	bio->bi_iter.bi_sector = 0;
+	bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
+	rqd->bio = bio;
+	rqd->nr_ppas = nr_rec_secs;
+
+	pgs_read = pblk_rb_read_to_bio_list(&pblk->rwb, bio, &recovery->failed,
+								nr_rec_secs);
+	if (pgs_read != nr_rec_secs) {
+		pr_err("pblk: could not read recovery entries\n");
+		goto err;
+	}
+
+	if (pblk_setup_w_rec_rq(pblk, rqd, c_ctx)) {
+		pr_err("pblk: could not setup recovery request\n");
+		goto err;
+	}
+
+#ifdef CONFIG_NVM_DEBUG
+	atomic_long_add(nr_rec_secs, &pblk->recov_writes);
+#endif
+
+	ret = pblk_submit_io(pblk, rqd);
+	if (ret) {
+		pr_err("pblk: I/O submission failed: %d\n", ret);
+		goto err;
+	}
+
+	mempool_free(recovery, pblk->rec_pool);
+	return;
+
+err:
+	bio_put(bio);
+	pblk_free_rqd(pblk, rqd, WRITE);
+}
+
+int pblk_recov_setup_rq(struct pblk *pblk, struct pblk_c_ctx *c_ctx,
+			struct pblk_rec_ctx *recovery, u64 *comp_bits,
+			unsigned int comp)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	int max_secs = nvm_max_phys_sects(dev);
+	struct nvm_rq *rec_rqd;
+	struct pblk_c_ctx *rec_ctx;
+	int nr_entries = c_ctx->nr_valid + c_ctx->nr_padded;
+
+	rec_rqd = pblk_alloc_rqd(pblk, WRITE);
+	if (IS_ERR(rec_rqd)) {
+		pr_err("pblk: could not create recovery req.\n");
+		return -ENOMEM;
+	}
+
+	rec_ctx = nvm_rq_to_pdu(rec_rqd);
+
+	/* Copy completion bitmap, but exclude the first X completed entries */
+	bitmap_shift_right((unsigned long int *)&rec_rqd->ppa_status,
+				(unsigned long int *)comp_bits,
+				comp, max_secs);
+
+	/* Save the context for the entries that need to be re-written and
+	 * update current context with the completed entries.
+	 */
+	rec_ctx->sentry = pblk_rb_wrap_pos(&pblk->rwb, c_ctx->sentry + comp);
+	if (comp >= c_ctx->nr_valid) {
+		rec_ctx->nr_valid = 0;
+		rec_ctx->nr_padded = nr_entries - comp;
+
+		c_ctx->nr_padded = comp - c_ctx->nr_valid;
+	} else {
+		rec_ctx->nr_valid = c_ctx->nr_valid - comp;
+		rec_ctx->nr_padded = c_ctx->nr_padded;
+
+		c_ctx->nr_valid = comp;
+		c_ctx->nr_padded = 0;
+	}
+
+	recovery->rqd = rec_rqd;
+	recovery->pblk = pblk;
+
+	return 0;
+}
+
+__le64 *pblk_recov_get_lba_list(struct pblk *pblk, struct line_emeta *emeta)
+{
+	u32 crc;
+
+	crc = pblk_calc_emeta_crc(pblk, emeta);
+	if (le32_to_cpu(emeta->crc) != crc)
+		return NULL;
+
+	if (le32_to_cpu(emeta->header.identifier) != PBLK_MAGIC)
+		return NULL;
+
+	return pblk_line_emeta_to_lbas(emeta);
+}
+
+static int pblk_recov_l2p_from_emeta(struct pblk *pblk, struct pblk_line *line)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct line_emeta *emeta = line->emeta;
+	__le64 *lba_list;
+	int data_start;
+	int nr_data_lbas, nr_valid_lbas, nr_lbas = 0;
+	int i;
+
+	lba_list = pblk_recov_get_lba_list(pblk, emeta);
+	if (!lba_list)
+		return 1;
+
+	data_start = pblk_line_smeta_start(pblk, line) + lm->smeta_sec;
+	nr_data_lbas = lm->sec_per_line - lm->emeta_sec;
+	nr_valid_lbas = le64_to_cpu(emeta->nr_valid_lbas);
+
+	for (i = data_start; i < nr_data_lbas && nr_lbas < nr_valid_lbas; i++) {
+		struct ppa_addr ppa;
+		int pos;
+
+		ppa = addr_to_pblk_ppa(pblk, i, line->id);
+		pos = pblk_ppa_to_pos(geo, ppa);
+
+		/* Do not update bad blocks */
+		if (test_bit(pos, line->blk_bitmap))
+			continue;
+
+		if (le64_to_cpu(lba_list[i]) == ADDR_EMPTY) {
+			spin_lock(&line->lock);
+			if (test_and_set_bit(i, line->invalid_bitmap))
+				WARN_ON_ONCE("pblk: rec. double invalidate:\n");
+			else
+				line->vsc--;
+			spin_unlock(&line->lock);
+
+			continue;
+		}
+
+		pblk_update_map(pblk, le64_to_cpu(lba_list[i]), ppa);
+		nr_lbas++;
+	}
+
+	if (nr_valid_lbas != nr_lbas)
+		pr_err("pblk: line %d - inconsistent lba list(%llu/%d)\n",
+				line->id, line->emeta->nr_valid_lbas, nr_lbas);
+
+	line->left_msecs = 0;
+
+	return 0;
+}
+
+static int pblk_calc_sec_in_line(struct pblk *pblk, struct pblk_line *line)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_line_meta *lm = &pblk->lm;
+	int nr_bb = bitmap_weight(line->blk_bitmap, lm->blk_per_line);
+
+	return lm->sec_per_line - lm->smeta_sec - lm->emeta_sec -
+				nr_bb * geo->sec_per_blk;
+}
+
+struct pblk_recov_alloc {
+	struct ppa_addr *ppa_list;
+	struct pblk_sec_meta *meta_list;
+	struct nvm_rq *rqd;
+	void *data;
+	dma_addr_t dma_ppa_list;
+	dma_addr_t dma_meta_list;
+};
+
+static int pblk_recov_read_oob(struct pblk *pblk, struct pblk_line *line,
+			       struct pblk_recov_alloc p, u64 r_ptr)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct ppa_addr *ppa_list;
+	struct pblk_sec_meta *meta_list;
+	struct nvm_rq *rqd;
+	struct bio *bio;
+	void *data;
+	dma_addr_t dma_ppa_list, dma_meta_list;
+	u64 r_ptr_int;
+	int left_ppas;
+	int rq_ppas, rq_len;
+	int i, j;
+	int ret = 0;
+	DECLARE_COMPLETION_ONSTACK(wait);
+
+	ppa_list = p.ppa_list;
+	meta_list = p.meta_list;
+	rqd = p.rqd;
+	data = p.data;
+	dma_ppa_list = p.dma_ppa_list;
+	dma_meta_list = p.dma_meta_list;
+
+	left_ppas = line->cur_sec - r_ptr;
+	if (!left_ppas)
+		return 0;
+
+	r_ptr_int = r_ptr;
+
+next_read_rq:
+	memset(rqd, 0, pblk_r_rq_size);
+
+	rq_ppas = pblk_calc_secs(pblk, left_ppas, 0);
+	if (!rq_ppas)
+		rq_ppas = pblk->min_write_pgs;
+	rq_len = rq_ppas * geo->sec_size;
+
+	bio = bio_map_kern(dev->q, data, rq_len, GFP_KERNEL);
+	if (IS_ERR(bio))
+		return PTR_ERR(bio);
+
+	bio->bi_iter.bi_sector = 0; /* internal bio */
+	bio_set_op_attrs(bio, REQ_OP_READ, 0);
+
+	rqd->bio = bio;
+	rqd->opcode = NVM_OP_PREAD;
+	rqd->flags = pblk_set_read_mode(pblk);
+	rqd->meta_list = meta_list;
+	rqd->nr_ppas = rq_ppas;
+	rqd->ppa_list = ppa_list;
+	rqd->dma_ppa_list = dma_ppa_list;
+	rqd->dma_meta_list = dma_meta_list;
+	rqd->end_io = pblk_end_io_sync;
+	rqd->private = &wait;
+
+	for (i = 0; i < rqd->nr_ppas; ) {
+		struct ppa_addr ppa;
+		int pos;
+
+		ppa = addr_to_gen_ppa(pblk, r_ptr_int, line->id);
+		pos = pblk_dev_ppa_to_pos(geo, ppa);
+
+		while (test_bit(pos, line->blk_bitmap)) {
+			r_ptr_int += pblk->min_write_pgs;
+			ppa = addr_to_gen_ppa(pblk, r_ptr_int, line->id);
+			pos = pblk_dev_ppa_to_pos(geo, ppa);
+		}
+
+		for (j = 0; j < pblk->min_write_pgs; j++, i++, r_ptr_int++)
+			rqd->ppa_list[i] =
+				addr_to_gen_ppa(pblk, r_ptr_int, line->id);
+	}
+
+	/* If read fails, more padding is needed */
+	ret = pblk_submit_io(pblk, rqd);
+	if (ret) {
+		pr_err("pblk: I/O submission failed: %d\n", ret);
+		return ret;
+	}
+
+	if (!wait_for_completion_io_timeout(&wait,
+				msecs_to_jiffies(PBLK_COMMAND_TIMEOUT_MS))) {
+		pr_err("pblk: L2P recovery read timed out\n");
+		return -EINTR;
+	}
+
+	reinit_completion(&wait);
+
+	/* At this point, the read should not fail. If it does, it is a problem
+	 * we cannot recover from here. Need FTL log.
+	 */
+	if (rqd->error) {
+		pr_err("pblk: L2P recovery failed (%d)\n", rqd->error);
+		return -EINTR;
+	}
+
+	for (i = 0; i < rqd->nr_ppas; i++) {
+		u64 lba = le64_to_cpu(meta_list[i].lba);
+
+		if (lba == ADDR_EMPTY || lba > pblk->rl.nr_secs)
+			continue;
+
+		pblk_update_map(pblk, lba, rqd->ppa_list[i]);
+	}
+
+	left_ppas -= rq_ppas;
+	if (left_ppas > 0)
+		goto next_read_rq;
+
+	return 0;
+}
+
+static int pblk_recov_pad_oob(struct pblk *pblk, struct pblk_line *line,
+			      struct pblk_recov_alloc p, int left_ppas)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct ppa_addr *ppa_list;
+	struct pblk_sec_meta *meta_list;
+	struct nvm_rq *rqd;
+	struct bio *bio;
+	void *data;
+	dma_addr_t dma_ppa_list, dma_meta_list;
+	__le64 *lba_list = pblk_line_emeta_to_lbas(line->emeta);
+	u64 w_ptr = line->cur_sec;
+	int left_line_ppas = line->left_msecs;
+	int rq_ppas, rq_len;
+	int i, j;
+	int ret = 0;
+	DECLARE_COMPLETION_ONSTACK(wait);
+
+	ppa_list = p.ppa_list;
+	meta_list = p.meta_list;
+	rqd = p.rqd;
+	data = p.data;
+	dma_ppa_list = p.dma_ppa_list;
+	dma_meta_list = p.dma_meta_list;
+
+next_pad_rq:
+	rq_ppas = pblk_calc_secs(pblk, left_ppas, 0);
+	if (!rq_ppas)
+		rq_ppas = pblk->min_write_pgs;
+	rq_len = rq_ppas * geo->sec_size;
+
+	bio = bio_map_kern(dev->q, data, rq_len, GFP_KERNEL);
+	if (IS_ERR(bio))
+		return PTR_ERR(bio);
+
+	bio->bi_iter.bi_sector = 0; /* internal bio */
+	bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
+
+	memset(rqd, 0, pblk_r_rq_size);
+
+	rqd->bio = bio;
+	rqd->opcode = NVM_OP_PWRITE;
+	rqd->flags = pblk_set_progr_mode(pblk, WRITE);
+	rqd->meta_list = meta_list;
+	rqd->nr_ppas = rq_ppas;
+	rqd->ppa_list = ppa_list;
+	rqd->dma_ppa_list = dma_ppa_list;
+	rqd->dma_meta_list = dma_meta_list;
+	rqd->end_io = pblk_end_io_sync;
+	rqd->private = &wait;
+
+	for (i = 0; i < rqd->nr_ppas; ) {
+		struct ppa_addr ppa;
+		int pos;
+
+		w_ptr = pblk_alloc_page(pblk, line, pblk->min_write_pgs);
+		ppa = addr_to_pblk_ppa(pblk, w_ptr, line->id);
+		pos = pblk_ppa_to_pos(geo, ppa);
+
+		while (test_bit(pos, line->blk_bitmap)) {
+			w_ptr += pblk->min_write_pgs;
+			ppa = addr_to_pblk_ppa(pblk, w_ptr, line->id);
+			pos = pblk_ppa_to_pos(geo, ppa);
+		}
+
+		for (j = 0; j < pblk->min_write_pgs; j++, i++, w_ptr++) {
+			struct ppa_addr dev_ppa;
+
+			dev_ppa = addr_to_gen_ppa(pblk, w_ptr, line->id);
+
+			pblk_map_invalidate(pblk, dev_ppa);
+			meta_list[i].lba = cpu_to_le64(ADDR_EMPTY);
+			lba_list[w_ptr] = cpu_to_le64(ADDR_EMPTY);
+			rqd->ppa_list[i] = dev_ppa;
+		}
+	}
+
+	ret = pblk_submit_io(pblk, rqd);
+	if (ret) {
+		pr_err("pblk: I/O submission failed: %d\n", ret);
+		return ret;
+	}
+
+	if (!wait_for_completion_io_timeout(&wait,
+				msecs_to_jiffies(PBLK_COMMAND_TIMEOUT_MS))) {
+		pr_err("pblk: L2P recovery write timed out\n");
+	}
+	reinit_completion(&wait);
+
+	left_line_ppas -= rq_ppas;
+	left_ppas -= rq_ppas;
+	if (left_ppas > 0 && left_line_ppas)
+		goto next_pad_rq;
+
+	return 0;
+}
+
+/* When this function is called, it means that not all upper pages have been
+ * written in a page that contains valid data. In order to recover this data, we
+ * first find the write pointer on the device, then we pad all necessary
+ * sectors, and finally attempt to read the valid data
+ */
+static int pblk_recov_scan_all_oob(struct pblk *pblk, struct pblk_line *line,
+				   struct pblk_recov_alloc p)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct ppa_addr *ppa_list;
+	struct pblk_sec_meta *meta_list;
+	struct nvm_rq *rqd;
+	struct bio *bio;
+	void *data;
+	dma_addr_t dma_ppa_list, dma_meta_list;
+	u64 w_ptr = 0, r_ptr;
+	int rq_ppas, rq_len;
+	int i, j;
+	int ret = 0;
+	int rec_round;
+	int left_ppas = pblk_calc_sec_in_line(pblk, line) - line->cur_sec;
+	DECLARE_COMPLETION_ONSTACK(wait);
+
+	ppa_list = p.ppa_list;
+	meta_list = p.meta_list;
+	rqd = p.rqd;
+	data = p.data;
+	dma_ppa_list = p.dma_ppa_list;
+	dma_meta_list = p.dma_meta_list;
+
+	/* we could recover up until the line write pointer */
+	r_ptr = line->cur_sec;
+	rec_round = 0;
+
+next_rq:
+	memset(rqd, 0, pblk_r_rq_size);
+
+	rq_ppas = pblk_calc_secs(pblk, left_ppas, 0);
+	if (!rq_ppas)
+		rq_ppas = pblk->min_write_pgs;
+	rq_len = rq_ppas * geo->sec_size;
+
+	bio = bio_map_kern(dev->q, data, rq_len, GFP_KERNEL);
+	if (IS_ERR(bio))
+		return PTR_ERR(bio);
+
+	bio->bi_iter.bi_sector = 0; /* internal bio */
+	bio_set_op_attrs(bio, REQ_OP_READ, 0);
+
+	rqd->bio = bio;
+	rqd->opcode = NVM_OP_PREAD;
+	rqd->flags = pblk_set_read_mode(pblk);
+	rqd->meta_list = meta_list;
+	rqd->nr_ppas = rq_ppas;
+	rqd->ppa_list = ppa_list;
+	rqd->dma_ppa_list = dma_ppa_list;
+	rqd->dma_meta_list = dma_meta_list;
+	rqd->end_io = pblk_end_io_sync;
+	rqd->private = &wait;
+
+	for (i = 0; i < rqd->nr_ppas; ) {
+		struct ppa_addr ppa;
+		int pos;
+
+		w_ptr = pblk_alloc_page(pblk, line, pblk->min_write_pgs);
+		ppa = addr_to_gen_ppa(pblk, w_ptr, line->id);
+		pos = pblk_dev_ppa_to_pos(geo, ppa);
+
+		while (test_bit(pos, line->blk_bitmap)) {
+			w_ptr += pblk->min_write_pgs;
+			ppa = addr_to_gen_ppa(pblk, w_ptr, line->id);
+			pos = pblk_dev_ppa_to_pos(geo, ppa);
+		}
+
+		for (j = 0; j < pblk->min_write_pgs; j++, i++, w_ptr++)
+			rqd->ppa_list[i] =
+				addr_to_gen_ppa(pblk, w_ptr, line->id);
+	}
+
+	ret = pblk_submit_io(pblk, rqd);
+	if (ret) {
+		pr_err("pblk: I/O submission failed: %d\n", ret);
+		return ret;
+	}
+
+	if (!wait_for_completion_io_timeout(&wait,
+				msecs_to_jiffies(PBLK_COMMAND_TIMEOUT_MS))) {
+		pr_err("pblk: L2P recovery read timed out\n");
+	}
+	reinit_completion(&wait);
+
+	/* This should not happen since the read failed during normal recovery,
+	 * but the media works funny sometimes...
+	 */
+	if (!rec_round++ && !rqd->error) {
+		rec_round = 0;
+		for (i = 0; i < rqd->nr_ppas; i++, r_ptr++) {
+			u64 lba = le64_to_cpu(meta_list[i].lba);
+
+			if (lba == ADDR_EMPTY || lba > pblk->rl.nr_secs)
+				continue;
+
+			pblk_update_map(pblk, lba, rqd->ppa_list[i]);
+		}
+	}
+
+	/* Reached the end of the written line */
+	if (rqd->error == NVM_RSP_ERR_EMPTYPAGE) {
+		int pad_secs, nr_error_bits, bit;
+		int ret;
+
+		bit = find_first_bit((void *)&rqd->ppa_status, rqd->nr_ppas);
+		nr_error_bits = rqd->nr_ppas - bit;
+
+		/* Roll back failed sectors */
+		line->cur_sec -= nr_error_bits;
+		line->left_msecs += nr_error_bits;
+		bitmap_clear(line->map_bitmap, line->cur_sec, nr_error_bits);
+
+		pad_secs = pblk_pad_distance(pblk);
+		if (pad_secs > line->left_msecs)
+			pad_secs = line->left_msecs;
+
+		ret = pblk_recov_pad_oob(pblk, line, p, pad_secs);
+		if (ret)
+			pr_err("pblk: OOB padding failed (err:%d)\n", ret);
+
+		ret = pblk_recov_read_oob(pblk, line, p, r_ptr);
+		if (ret)
+			pr_err("pblk: OOB read failed (err:%d)\n", ret);
+
+		line->left_ssecs = line->left_msecs;
+		left_ppas = 0;
+	}
+
+	left_ppas -= rq_ppas;
+	if (left_ppas > 0)
+		goto next_rq;
+
+	return ret;
+}
+
+static int pblk_recov_scan_oob(struct pblk *pblk, struct pblk_line *line,
+			       struct pblk_recov_alloc p, int *done)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct ppa_addr *ppa_list;
+	struct pblk_sec_meta *meta_list;
+	struct nvm_rq *rqd;
+	struct bio *bio;
+	void *data;
+	dma_addr_t dma_ppa_list, dma_meta_list;
+	u64 paddr;
+	int rq_ppas, rq_len;
+	int i, j;
+	int ret = 0;
+	int left_ppas = pblk_calc_sec_in_line(pblk, line);
+	DECLARE_COMPLETION_ONSTACK(wait);
+
+	ppa_list = p.ppa_list;
+	meta_list = p.meta_list;
+	rqd = p.rqd;
+	data = p.data;
+	dma_ppa_list = p.dma_ppa_list;
+	dma_meta_list = p.dma_meta_list;
+
+	*done = 1;
+
+next_rq:
+	memset(rqd, 0, pblk_r_rq_size);
+
+	rq_ppas = pblk_calc_secs(pblk, left_ppas, 0);
+	if (!rq_ppas)
+		rq_ppas = pblk->min_write_pgs;
+	rq_len = rq_ppas * geo->sec_size;
+
+	bio = bio_map_kern(dev->q, data, rq_len, GFP_KERNEL);
+	if (IS_ERR(bio))
+		return PTR_ERR(bio);
+
+	bio->bi_iter.bi_sector = 0; /* internal bio */
+	bio_set_op_attrs(bio, REQ_OP_READ, 0);
+
+	rqd->bio = bio;
+	rqd->opcode = NVM_OP_PREAD;
+	rqd->flags = pblk_set_read_mode(pblk);
+	rqd->meta_list = meta_list;
+	rqd->nr_ppas = rq_ppas;
+	rqd->ppa_list = ppa_list;
+	rqd->dma_ppa_list = dma_ppa_list;
+	rqd->dma_meta_list = dma_meta_list;
+	rqd->end_io = pblk_end_io_sync;
+	rqd->private = &wait;
+
+	for (i = 0; i < rqd->nr_ppas; ) {
+		struct ppa_addr ppa;
+		int pos;
+
+		paddr = pblk_alloc_page(pblk, line, pblk->min_write_pgs);
+		ppa = addr_to_gen_ppa(pblk, paddr, line->id);
+		pos = pblk_dev_ppa_to_pos(geo, ppa);
+
+		while (test_bit(pos, line->blk_bitmap)) {
+			paddr += pblk->min_write_pgs;
+			ppa = addr_to_gen_ppa(pblk, paddr, line->id);
+			pos = pblk_dev_ppa_to_pos(geo, ppa);
+		}
+
+		for (j = 0; j < pblk->min_write_pgs; j++, i++, paddr++)
+			rqd->ppa_list[i] =
+				addr_to_gen_ppa(pblk, paddr, line->id);
+	}
+
+	ret = pblk_submit_io(pblk, rqd);
+	if (ret) {
+		pr_err("pblk: I/O submission failed: %d\n", ret);
+		bio_put(bio);
+		return ret;
+	}
+
+	if (!wait_for_completion_io_timeout(&wait,
+				msecs_to_jiffies(PBLK_COMMAND_TIMEOUT_MS))) {
+		pr_err("pblk: L2P recovery read timed out\n");
+	}
+	reinit_completion(&wait);
+
+	/* Reached the end of the written line */
+	if (rqd->error) {
+		int nr_error_bits, bit;
+
+		bit = find_first_bit((void *)&rqd->ppa_status, rqd->nr_ppas);
+		nr_error_bits = rqd->nr_ppas - bit;
+
+		/* Roll back failed sectors */
+		line->cur_sec -= nr_error_bits;
+		line->left_msecs += nr_error_bits;
+		line->left_ssecs = line->left_msecs;
+		bitmap_clear(line->map_bitmap, line->cur_sec, nr_error_bits);
+
+		left_ppas = 0;
+		rqd->nr_ppas = bit;
+
+		if (rqd->error != NVM_RSP_ERR_EMPTYPAGE)
+			*done = 0;
+	}
+
+	for (i = 0; i < rqd->nr_ppas; i++) {
+		u64 lba = le64_to_cpu(meta_list[i].lba);
+
+		if (lba == ADDR_EMPTY || lba > pblk->rl.nr_secs)
+			continue;
+
+		pblk_update_map(pblk, lba, rqd->ppa_list[i]);
+	}
+
+	left_ppas -= rq_ppas;
+	if (left_ppas > 0)
+		goto next_rq;
+
+	return ret;
+}
+
+/* Scan line for lbas on out of bound area */
+static int pblk_recov_l2p_from_oob(struct pblk *pblk, struct pblk_line *line)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct nvm_rq *rqd;
+	struct ppa_addr *ppa_list;
+	struct pblk_sec_meta *meta_list;
+	struct pblk_recov_alloc p;
+	void *data;
+	dma_addr_t dma_ppa_list, dma_meta_list;
+	int done, ret = 0;
+
+	rqd = pblk_alloc_rqd(pblk, READ);
+	if (IS_ERR(rqd))
+		return PTR_ERR(rqd);
+
+	meta_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL, &dma_meta_list);
+	if (!meta_list) {
+		ret = -ENOMEM;
+		goto free_rqd;
+	}
+
+	ppa_list = (void *)(meta_list) + pblk_dma_meta_size;
+	dma_ppa_list = dma_meta_list + pblk_dma_meta_size;
+
+	data = kcalloc(pblk->max_write_pgs, geo->sec_size, GFP_KERNEL);
+	if (!data) {
+		ret = -ENOMEM;
+		goto free_meta_list;
+	}
+
+	p.ppa_list = ppa_list;
+	p.meta_list = meta_list;
+	p.rqd = rqd;
+	p.data = data;
+	p.dma_ppa_list = dma_ppa_list;
+	p.dma_meta_list = dma_meta_list;
+
+	ret = pblk_recov_scan_oob(pblk, line, p, &done);
+	if (ret) {
+		pr_err("pblk: could not recover L2P from OOB\n");
+		goto out;
+	}
+
+	if (!done) {
+		ret = pblk_recov_scan_all_oob(pblk, line, p);
+		if (ret) {
+			pr_err("pblk: could not recover L2P from OOB\n");
+			goto out;
+		}
+	}
+
+	if (pblk_line_is_full(line))
+		pblk_line_recov_close(pblk, line);
+
+out:
+	kfree(data);
+free_meta_list:
+	nvm_dev_dma_free(dev->parent, meta_list, dma_meta_list);
+free_rqd:
+	pblk_free_rqd(pblk, rqd, READ);
+
+	return ret;
+}
+
+/* Insert lines ordered by sequence number (seq_num) on list */
+static void pblk_recov_line_add_ordered(struct list_head *head,
+					struct pblk_line *line)
+{
+	struct pblk_line *t = NULL;
+
+	list_for_each_entry(t, head, list)
+		if (t->seq_nr > line->seq_nr)
+			break;
+
+	__list_add(&line->list, t->list.prev, &t->list);
+}
+
+struct pblk_line *pblk_recov_l2p(struct pblk *pblk)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct pblk_line *line, *tline, *data_line = NULL;
+	struct line_smeta *smeta;
+	struct line_emeta *emeta;
+	int found_lines = 0, recovered_lines = 0, open_lines = 0;
+	int is_next = 0;
+	int meta_line;
+	int i, valid_uuid = 0;
+	LIST_HEAD(recov_list);
+
+	/* TODO: Implement FTL snapshot */
+
+	/* Scan recovery - takes place when FTL snapshot fails */
+	spin_lock(&l_mg->free_lock);
+	meta_line = find_first_zero_bit(&l_mg->meta_bitmap, PBLK_DATA_LINES);
+	set_bit(meta_line, &l_mg->meta_bitmap);
+	smeta = l_mg->sline_meta[meta_line].meta;
+	emeta = l_mg->eline_meta[meta_line].meta;
+	spin_unlock(&l_mg->free_lock);
+
+	/* Order data lines using their sequence number */
+	for (i = 0; i < l_mg->nr_lines; i++) {
+		u32 crc;
+
+		line = &pblk->lines[i];
+
+		memset(smeta, 0, lm->smeta_len);
+		line->smeta = smeta;
+		line->lun_bitmap = ((void *)(smeta)) +
+						sizeof(struct line_smeta);
+
+		/* Lines that cannot be read are assumed as not written here */
+		if (pblk_line_read_smeta(pblk, line))
+			continue;
+
+		crc = pblk_calc_smeta_crc(pblk, smeta);
+		if (le32_to_cpu(smeta->crc) != crc)
+			continue;
+
+		if (le32_to_cpu(smeta->header.identifier) != PBLK_MAGIC)
+			continue;
+
+		if (le16_to_cpu(smeta->header.version) != 1) {
+			pr_err("pblk: found incompatible line version %u\n",
+					smeta->header.version);
+			return ERR_PTR(-EINVAL);
+		}
+
+		/* The first valid instance uuid is used for initialization */
+		if (!valid_uuid) {
+			memcpy(pblk->instance_uuid, smeta->header.uuid, 16);
+			valid_uuid = 1;
+		}
+
+		if (memcmp(pblk->instance_uuid, smeta->header.uuid, 16)) {
+			pr_debug("pblk: ignore line %u due to uuid mismatch\n",
+					i);
+			continue;
+		}
+
+		/* Update line metadata */
+		spin_lock(&line->lock);
+		line->id = le32_to_cpu(line->smeta->header.id);
+		line->type = le16_to_cpu(line->smeta->header.type);
+		line->seq_nr = le64_to_cpu(line->smeta->seq_nr);
+		spin_unlock(&line->lock);
+
+		/* Update general metadata */
+		spin_lock(&l_mg->free_lock);
+		if (line->seq_nr >= l_mg->d_seq_nr)
+			l_mg->d_seq_nr = line->seq_nr + 1;
+		l_mg->nr_free_lines--;
+		spin_unlock(&l_mg->free_lock);
+
+		if (pblk_line_recov_alloc(pblk, line))
+			goto out;
+
+		pblk_recov_line_add_ordered(&recov_list, line);
+		found_lines++;
+		pr_debug("pblk: recovering data line %d, seq:%llu\n",
+						line->id, smeta->seq_nr);
+	}
+
+	if (!found_lines) {
+		pblk_setup_uuid(pblk);
+
+		spin_lock(&l_mg->free_lock);
+		WARN_ON_ONCE(!test_and_clear_bit(meta_line,
+							&l_mg->meta_bitmap));
+		spin_unlock(&l_mg->free_lock);
+
+		goto out;
+	}
+
+	/* Verify closed blocks and recover this portion of L2P table*/
+	list_for_each_entry_safe(line, tline, &recov_list, list) {
+		int off, nr_bb;
+
+		recovered_lines++;
+		/* Calculate where emeta starts based on the line bb */
+		off = lm->sec_per_line - lm->emeta_sec;
+		nr_bb = bitmap_weight(line->blk_bitmap, lm->blk_per_line);
+		off -= nr_bb * geo->sec_per_pl;
+
+		memset(emeta, 0, lm->emeta_len);
+		line->emeta = emeta;
+		line->emeta_ssec = off;
+
+		if (pblk_line_read_emeta(pblk, line)) {
+			pblk_recov_l2p_from_oob(pblk, line);
+			goto next;
+		}
+
+		if (pblk_recov_l2p_from_emeta(pblk, line))
+			pblk_recov_l2p_from_oob(pblk, line);
+
+next:
+		if (pblk_line_is_full(line)) {
+			struct list_head *move_list;
+
+			spin_lock(&line->lock);
+			line->state = PBLK_LINESTATE_CLOSED;
+			move_list = pblk_line_gc_list(pblk, line);
+			spin_unlock(&line->lock);
+
+			spin_lock(&l_mg->gc_lock);
+			list_move_tail(&line->list, move_list);
+			spin_unlock(&l_mg->gc_lock);
+
+			mempool_free(line->map_bitmap, pblk->line_meta_pool);
+			line->map_bitmap = NULL;
+			line->smeta = NULL;
+			line->emeta = NULL;
+		} else {
+			if (open_lines > 1)
+				pr_err("pblk: failed to recover L2P\n");
+
+			open_lines++;
+			line->meta_line = meta_line;
+			data_line = line;
+		}
+	}
+
+	spin_lock(&l_mg->free_lock);
+	if (!open_lines) {
+		WARN_ON_ONCE(!test_and_clear_bit(meta_line,
+							&l_mg->meta_bitmap));
+		pblk_line_replace_data(pblk);
+	} else {
+		/* Allocate next line for preparation */
+		l_mg->data_next = pblk_line_get(pblk);
+		if (l_mg->data_next) {
+			l_mg->data_next->seq_nr = l_mg->d_seq_nr++;
+			l_mg->data_next->type = PBLK_LINETYPE_DATA;
+			is_next = 1;
+		}
+	}
+	spin_unlock(&l_mg->free_lock);
+
+	if (is_next) {
+		pblk_line_erase(pblk, l_mg->data_next);
+		pblk_rl_free_lines_dec(&pblk->rl, l_mg->data_next);
+	}
+
+out:
+	if (found_lines != recovered_lines)
+		pr_err("pblk: failed to recover all found lines %d/%d\n",
+						found_lines, recovered_lines);
+
+	return data_line;
+}
+
+/*
+ * Pad until smeta can be read on current data line
+ */
+void pblk_recov_pad(struct pblk *pblk)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_line *line;
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct nvm_rq *rqd;
+	struct pblk_recov_alloc p;
+	struct ppa_addr *ppa_list;
+	struct pblk_sec_meta *meta_list;
+	void *data;
+	dma_addr_t dma_ppa_list, dma_meta_list;
+
+	spin_lock(&l_mg->free_lock);
+	line = l_mg->data_line;
+	spin_unlock(&l_mg->free_lock);
+
+	rqd = pblk_alloc_rqd(pblk, READ);
+	if (IS_ERR(rqd))
+		return;
+
+	meta_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL, &dma_meta_list);
+	if (!meta_list)
+		goto free_rqd;
+
+	ppa_list = (void *)(meta_list) + pblk_dma_meta_size;
+	dma_ppa_list = dma_meta_list + pblk_dma_meta_size;
+
+	data = kcalloc(pblk->max_write_pgs, geo->sec_size, GFP_KERNEL);
+	if (!data)
+		goto free_meta_list;
+
+	p.ppa_list = ppa_list;
+	p.meta_list = meta_list;
+	p.rqd = rqd;
+	p.data = data;
+	p.dma_ppa_list = dma_ppa_list;
+	p.dma_meta_list = dma_meta_list;
+
+	if (pblk_recov_pad_oob(pblk, line, p, line->left_msecs)) {
+		pr_err("pblk: Tear down padding failed\n");
+		goto free_data;
+	}
+
+	pblk_line_close(pblk, line);
+
+free_data:
+	kfree(data);
+free_meta_list:
+	nvm_dev_dma_free(dev->parent, meta_list, dma_meta_list);
+free_rqd:
+	pblk_free_rqd(pblk, rqd, READ);
+}

drivers/lightnvm/pblk-rl.c

+/*
+ * Copyright (C) 2016 CNEX Labs
+ * Initial release: Javier Gonzalez <javier@cnexlabs.com>
+ *                  Matias Bjorling <matias@cnexlabs.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * pblk-rl.c - pblk's rate limiter for user I/O
+ *
+ */
+
+#include "pblk.h"
+
+static void pblk_rl_kick_u_timer(struct pblk_rl *rl)
+{
+	mod_timer(&rl->u_timer, jiffies + msecs_to_jiffies(5000));
+}
+
+int pblk_rl_user_may_insert(struct pblk_rl *rl, int nr_entries)
+{
+	int rb_user_cnt = atomic_read(&rl->rb_user_cnt);
+
+	return (!(rb_user_cnt + nr_entries > rl->rb_user_max));
+}
+
+int pblk_rl_gc_may_insert(struct pblk_rl *rl, int nr_entries)
+{
+	int rb_gc_cnt = atomic_read(&rl->rb_gc_cnt);
+	int rb_user_active;
+
+	/* If there is no user I/O let GC take over space on the write buffer */
+	rb_user_active = READ_ONCE(rl->rb_user_active);
+	return (!(rb_gc_cnt + nr_entries > rl->rb_gc_max && rb_user_active));
+}
+
+void pblk_rl_user_in(struct pblk_rl *rl, int nr_entries)
+{
+	atomic_add(nr_entries, &rl->rb_user_cnt);
+
+	/* Release user I/O state. Protect from GC */
+	smp_store_release(&rl->rb_user_active, 1);
+	pblk_rl_kick_u_timer(rl);
+}
+
+void pblk_rl_gc_in(struct pblk_rl *rl, int nr_entries)
+{
+	atomic_add(nr_entries, &rl->rb_gc_cnt);
+}
+
+void pblk_rl_out(struct pblk_rl *rl, int nr_user, int nr_gc)
+{
+	atomic_sub(nr_user, &rl->rb_user_cnt);
+	atomic_sub(nr_gc, &rl->rb_gc_cnt);
+}
+
+unsigned long pblk_rl_nr_free_blks(struct pblk_rl *rl)
+{
+	return atomic_read(&rl->free_blocks);
+}
+
+/*
+ * We check for (i) the number of free blocks in the current LUN and (ii) the
+ * total number of free blocks in the pblk instance. This is to even out the
+ * number of free blocks on each LUN when GC kicks in.
+ *
+ * Only the total number of free blocks is used to configure the rate limiter.
+ */
+static int pblk_rl_update_rates(struct pblk_rl *rl, unsigned long max)
+{
+	unsigned long free_blocks = pblk_rl_nr_free_blks(rl);
+
+	if (free_blocks >= rl->high) {
+		rl->rb_user_max = max - rl->rb_gc_rsv;
+		rl->rb_gc_max = rl->rb_gc_rsv;
+		rl->rb_state = PBLK_RL_HIGH;
+	} else if (free_blocks < rl->high) {
+		int shift = rl->high_pw - rl->rb_windows_pw;
+		int user_windows = free_blocks >> shift;
+		int user_max = user_windows << PBLK_MAX_REQ_ADDRS_PW;
+		int gc_max;
+
+		rl->rb_user_max = user_max;
+		gc_max = max - rl->rb_user_max;
+		rl->rb_gc_max = max(gc_max, rl->rb_gc_rsv);
+
+		if (free_blocks > rl->low)
+			rl->rb_state = PBLK_RL_MID;
+		else
+			rl->rb_state = PBLK_RL_LOW;
+	}
+
+	return rl->rb_state;
+}
+
+void pblk_rl_set_gc_rsc(struct pblk_rl *rl, int rsv)
+{
+	rl->rb_gc_rsv = rl->rb_gc_max = rsv;
+}
+
+void pblk_rl_free_lines_inc(struct pblk_rl *rl, struct pblk_line *line)
+{
+	struct pblk *pblk = container_of(rl, struct pblk, rl);
+	int ret;
+
+	atomic_add(line->blk_in_line, &rl->free_blocks);
+	/* Rates will not change that often - no need to lock update */
+	ret = pblk_rl_update_rates(rl, rl->rb_budget);
+
+	if (ret == (PBLK_RL_MID | PBLK_RL_LOW))
+		pblk_gc_should_start(pblk);
+	else
+		pblk_gc_should_stop(pblk);
+}
+
+void pblk_rl_free_lines_dec(struct pblk_rl *rl, struct pblk_line *line)
+{
+	struct pblk *pblk = container_of(rl, struct pblk, rl);
+	int ret;
+
+	atomic_sub(line->blk_in_line, &rl->free_blocks);
+
+	/* Rates will not change that often - no need to lock update */
+	ret = pblk_rl_update_rates(rl, rl->rb_budget);
+	if (ret == (PBLK_RL_MID | PBLK_RL_LOW))
+		pblk_gc_should_start(pblk);
+	else
+		pblk_gc_should_stop(pblk);
+}
+
+int pblk_rl_gc_thrs(struct pblk_rl *rl)
+{
+	return rl->high;
+}
+
+int pblk_rl_sysfs_rate_show(struct pblk_rl *rl)
+{
+	return rl->rb_user_max;
+}
+
+static void pblk_rl_u_timer(unsigned long data)
+{
+	struct pblk_rl *rl = (struct pblk_rl *)data;
+
+	/* Release user I/O state. Protect from GC */
+	smp_store_release(&rl->rb_user_active, 0);
+}
+
+void pblk_rl_free(struct pblk_rl *rl)
+{
+	del_timer(&rl->u_timer);
+}
+
+void pblk_rl_init(struct pblk_rl *rl, int budget)
+{
+	unsigned int rb_windows;
+
+	rl->high = rl->total_blocks / PBLK_USER_HIGH_THRS;
+	rl->low = rl->total_blocks / PBLK_USER_LOW_THRS;
+	rl->high_pw = get_count_order(rl->high);
+
+	/* This will always be a power-of-2 */
+	rb_windows = budget / PBLK_MAX_REQ_ADDRS;
+	rl->rb_windows_pw = get_count_order(rb_windows) + 1;
+
+	/* To start with, all buffer is available to user I/O writers */
+	rl->rb_budget = budget;
+	rl->rb_user_max = budget;
+	atomic_set(&rl->rb_user_cnt, 0);
+	rl->rb_gc_max = 0;
+	rl->rb_state = PBLK_RL_HIGH;
+	atomic_set(&rl->rb_gc_cnt, 0);
+
+	setup_timer(&rl->u_timer, pblk_rl_u_timer, (unsigned long)rl);
+	rl->rb_user_active = 0;
+}

drivers/lightnvm/pblk-sysfs.c

+/*
+ * Copyright (C) 2016 CNEX Labs
+ * Initial release: Javier Gonzalez <javier@cnexlabs.com>
+ *                  Matias Bjorling <matias@cnexlabs.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * Implementation of a physical block-device target for Open-channel SSDs.
+ *
+ * pblk-sysfs.c - pblk's sysfs
+ *
+ */
+
+#include "pblk.h"
+
+static ssize_t pblk_sysfs_luns_show(struct pblk *pblk, char *page)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_lun *rlun;
+	ssize_t sz = 0;
+	int i;
+
+	for (i = 0; i < geo->nr_luns; i++) {
+		int active = 1;
+
+		rlun = &pblk->luns[i];
+		if (!down_trylock(&rlun->wr_sem)) {
+			active = 0;
+			up(&rlun->wr_sem);
+		}
+		sz += snprintf(page + sz, PAGE_SIZE - sz,
+				"pblk: pos:%d, ch:%d, lun:%d - %d\n",
+					i,
+					rlun->bppa.g.ch,
+					rlun->bppa.g.lun,
+					active);
+	}
+
+	return sz;
+}
+
+static ssize_t pblk_sysfs_rate_limiter(struct pblk *pblk, char *page)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	int free_blocks, total_blocks;
+	int rb_user_max, rb_user_cnt;
+	int rb_gc_max, rb_gc_rsv, rb_gc_cnt, rb_budget, rb_state;
+
+	free_blocks = atomic_read(&pblk->rl.free_blocks);
+	rb_user_max = pblk->rl.rb_user_max;
+	rb_user_cnt = atomic_read(&pblk->rl.rb_user_cnt);
+	rb_gc_max = pblk->rl.rb_gc_max;
+	rb_gc_rsv = pblk->rl.rb_gc_rsv;
+	rb_gc_cnt = atomic_read(&pblk->rl.rb_gc_cnt);
+	rb_budget = pblk->rl.rb_budget;
+	rb_state = pblk->rl.rb_state;
+
+	total_blocks = geo->blks_per_lun * geo->nr_luns;
+
+	return snprintf(page, PAGE_SIZE,
+		"u:%u/%u,gc:%u/%u/%u(%u/%u)(stop:<%u,full:>%u,free:%d/%d)-%d\n",
+				rb_user_cnt,
+				rb_user_max,
+				rb_gc_cnt,
+				rb_gc_max,
+				rb_gc_rsv,
+				rb_state,
+				rb_budget,
+				pblk->rl.low,
+				pblk->rl.high,
+				free_blocks,
+				total_blocks,
+				READ_ONCE(pblk->rl.rb_user_active));
+}
+
+static ssize_t pblk_sysfs_gc_state_show(struct pblk *pblk, char *page)
+{
+	int gc_enabled, gc_active;
+
+	pblk_gc_sysfs_state_show(pblk, &gc_enabled, &gc_active);
+	return snprintf(page, PAGE_SIZE, "gc_enabled=%d, gc_active=%d\n",
+					gc_enabled, gc_active);
+}
+
+static ssize_t pblk_sysfs_stats(struct pblk *pblk, char *page)
+{
+	ssize_t sz;
+
+	sz = snprintf(page, PAGE_SIZE,
+			"read_failed=%lu, read_high_ecc=%lu, read_empty=%lu, read_failed_gc=%lu, write_failed=%lu, erase_failed=%lu\n",
+			atomic_long_read(&pblk->read_failed),
+			atomic_long_read(&pblk->read_high_ecc),
+			atomic_long_read(&pblk->read_empty),
+			atomic_long_read(&pblk->read_failed_gc),
+			atomic_long_read(&pblk->write_failed),
+			atomic_long_read(&pblk->erase_failed));
+
+	return sz;
+}
+
+static ssize_t pblk_sysfs_write_buffer(struct pblk *pblk, char *page)
+{
+	return pblk_rb_sysfs(&pblk->rwb, page);
+}
+
+static ssize_t pblk_sysfs_ppaf(struct pblk *pblk, char *page)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	ssize_t sz = 0;
+
+	sz = snprintf(page, PAGE_SIZE - sz,
+		"g:(b:%d)blk:%d/%d,pg:%d/%d,lun:%d/%d,ch:%d/%d,pl:%d/%d,sec:%d/%d\n",
+		pblk->ppaf_bitsize,
+		pblk->ppaf.blk_offset, geo->ppaf.blk_len,
+		pblk->ppaf.pg_offset, geo->ppaf.pg_len,
+		pblk->ppaf.lun_offset, geo->ppaf.lun_len,
+		pblk->ppaf.ch_offset, geo->ppaf.ch_len,
+		pblk->ppaf.pln_offset, geo->ppaf.pln_len,
+		pblk->ppaf.sec_offset, geo->ppaf.sect_len);
+
+	sz += snprintf(page + sz, PAGE_SIZE - sz,
+		"d:blk:%d/%d,pg:%d/%d,lun:%d/%d,ch:%d/%d,pl:%d/%d,sec:%d/%d\n",
+		geo->ppaf.blk_offset, geo->ppaf.blk_len,
+		geo->ppaf.pg_offset, geo->ppaf.pg_len,
+		geo->ppaf.lun_offset, geo->ppaf.lun_len,
+		geo->ppaf.ch_offset, geo->ppaf.ch_len,
+		geo->ppaf.pln_offset, geo->ppaf.pln_len,
+		geo->ppaf.sect_offset, geo->ppaf.sect_len);
+
+	return sz;
+}
+
+static ssize_t pblk_sysfs_lines(struct pblk *pblk, char *page)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct pblk_line_mgmt *l_mg = &pblk->l_mg;
+	struct pblk_line *line;
+	ssize_t sz = 0;
+	int nr_free_lines;
+	int cur_data, cur_log;
+	int free_line_cnt = 0, closed_line_cnt = 0;
+	int d_line_cnt = 0, l_line_cnt = 0;
+	int gc_full = 0, gc_high = 0, gc_mid = 0, gc_low = 0, gc_empty = 0;
+	int free = 0, bad = 0, cor = 0;
+	int msecs = 0, ssecs = 0, cur_sec = 0, vsc = 0, sec_in_line = 0;
+	int map_weight = 0, meta_weight = 0;
+
+	spin_lock(&l_mg->free_lock);
+	cur_data = (l_mg->data_line) ? l_mg->data_line->id : -1;
+	cur_log = (l_mg->log_line) ? l_mg->log_line->id : -1;
+	nr_free_lines = l_mg->nr_free_lines;
+
+	list_for_each_entry(line, &l_mg->free_list, list)
+		free_line_cnt++;
+	spin_unlock(&l_mg->free_lock);
+
+	spin_lock(&l_mg->gc_lock);
+	list_for_each_entry(line, &l_mg->gc_full_list, list) {
+		if (line->type == PBLK_LINETYPE_DATA)
+			d_line_cnt++;
+		else if (line->type == PBLK_LINETYPE_LOG)
+			l_line_cnt++;
+		closed_line_cnt++;
+		gc_full++;
+	}
+
+	list_for_each_entry(line, &l_mg->gc_high_list, list) {
+		if (line->type == PBLK_LINETYPE_DATA)
+			d_line_cnt++;
+		else if (line->type == PBLK_LINETYPE_LOG)
+			l_line_cnt++;
+		closed_line_cnt++;
+		gc_high++;
+	}
+
+	list_for_each_entry(line, &l_mg->gc_mid_list, list) {
+		if (line->type == PBLK_LINETYPE_DATA)
+			d_line_cnt++;
+		else if (line->type == PBLK_LINETYPE_LOG)
+			l_line_cnt++;
+		closed_line_cnt++;
+		gc_mid++;
+	}
+
+	list_for_each_entry(line, &l_mg->gc_low_list, list) {
+		if (line->type == PBLK_LINETYPE_DATA)
+			d_line_cnt++;
+		else if (line->type == PBLK_LINETYPE_LOG)
+			l_line_cnt++;
+		closed_line_cnt++;
+		gc_low++;
+	}
+
+	list_for_each_entry(line, &l_mg->gc_empty_list, list) {
+		if (line->type == PBLK_LINETYPE_DATA)
+			d_line_cnt++;
+		else if (line->type == PBLK_LINETYPE_LOG)
+			l_line_cnt++;
+		closed_line_cnt++;
+		gc_empty++;
+	}
+
+	list_for_each_entry(line, &l_mg->free_list, list)
+		free++;
+	list_for_each_entry(line, &l_mg->bad_list, list)
+		bad++;
+	list_for_each_entry(line, &l_mg->corrupt_list, list)
+		cor++;
+	spin_unlock(&l_mg->gc_lock);
+
+	spin_lock(&l_mg->free_lock);
+	if (l_mg->data_line) {
+		cur_sec = l_mg->data_line->cur_sec;
+		msecs = l_mg->data_line->left_msecs;
+		ssecs = l_mg->data_line->left_ssecs;
+		vsc = l_mg->data_line->vsc;
+		sec_in_line = l_mg->data_line->sec_in_line;
+		meta_weight = bitmap_weight(&l_mg->meta_bitmap,
+							PBLK_DATA_LINES);
+		map_weight = bitmap_weight(l_mg->data_line->map_bitmap,
+							lm->sec_per_line);
+	}
+	spin_unlock(&l_mg->free_lock);
+
+	if (nr_free_lines != free_line_cnt)
+		pr_err("pblk: corrupted free line list\n");
+
+	sz = snprintf(page, PAGE_SIZE - sz,
+		"line: nluns:%d, nblks:%d, nsecs:%d\n",
+		geo->nr_luns, lm->blk_per_line, lm->sec_per_line);
+
+	sz += snprintf(page + sz, PAGE_SIZE - sz,
+		"lines:d:%d,l:%d-f:%d(%d),b:%d,co:%d,c:%d(d:%d,l:%d)t:%d\n",
+					cur_data, cur_log,
+					free, nr_free_lines, bad, cor,
+					closed_line_cnt,
+					d_line_cnt, l_line_cnt,
+					l_mg->nr_lines);
+
+	sz += snprintf(page + sz, PAGE_SIZE - sz,
+		"GC: full:%d, high:%d, mid:%d, low:%d, empty:%d, queue:%d\n",
+			gc_full, gc_high, gc_mid, gc_low, gc_empty,
+			atomic_read(&pblk->gc.inflight_gc));
+
+	sz += snprintf(page + sz, PAGE_SIZE - sz,
+		"data (%d) cur:%d, left:%d/%d, vsc:%d, s:%d, map:%d/%d (%d)\n",
+			cur_data, cur_sec, msecs, ssecs, vsc, sec_in_line,
+			map_weight, lm->sec_per_line, meta_weight);
+
+	return sz;
+}
+
+static ssize_t pblk_sysfs_lines_info(struct pblk *pblk, char *page)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	struct pblk_line_meta *lm = &pblk->lm;
+	ssize_t sz = 0;
+
+	sz = snprintf(page, PAGE_SIZE - sz,
+				"smeta - len:%d, secs:%d\n",
+					lm->smeta_len, lm->smeta_sec);
+	sz += snprintf(page + sz, PAGE_SIZE - sz,
+				"emeta - len:%d, sec:%d, bb_start:%d\n",
+					lm->emeta_len, lm->emeta_sec,
+					lm->emeta_bb);
+	sz += snprintf(page + sz, PAGE_SIZE - sz,
+				"bitmap lengths: sec:%d, blk:%d, lun:%d\n",
+					lm->sec_bitmap_len,
+					lm->blk_bitmap_len,
+					lm->lun_bitmap_len);
+	sz += snprintf(page + sz, PAGE_SIZE - sz,
+				"blk_line:%d, sec_line:%d, sec_blk:%d\n",
+					lm->blk_per_line,
+					lm->sec_per_line,
+					geo->sec_per_blk);
+
+	return sz;
+}
+
+#ifdef CONFIG_NVM_DEBUG
+static ssize_t pblk_sysfs_stats_debug(struct pblk *pblk, char *page)
+{
+	return snprintf(page, PAGE_SIZE,
+		"%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\t%lu\n",
+			atomic_long_read(&pblk->inflight_writes),
+			atomic_long_read(&pblk->inflight_reads),
+			atomic_long_read(&pblk->req_writes),
+			atomic_long_read(&pblk->nr_flush),
+			atomic_long_read(&pblk->padded_writes),
+			atomic_long_read(&pblk->padded_wb),
+			atomic_long_read(&pblk->sub_writes),
+			atomic_long_read(&pblk->sync_writes),
+			atomic_long_read(&pblk->compl_writes),
+			atomic_long_read(&pblk->recov_writes),
+			atomic_long_read(&pblk->recov_gc_writes),
+			atomic_long_read(&pblk->recov_gc_reads),
+			atomic_long_read(&pblk->sync_reads));
+}
+#endif
+
+static ssize_t pblk_sysfs_rate_store(struct pblk *pblk, const char *page,
+				     size_t len)
+{
+	struct pblk_gc *gc = &pblk->gc;
+	size_t c_len;
+	int value;
+
+	c_len = strcspn(page, "\n");
+	if (c_len >= len)
+		return -EINVAL;
+
+	if (kstrtouint(page, 0, &value))
+		return -EINVAL;
+
+	spin_lock(&gc->lock);
+	pblk_rl_set_gc_rsc(&pblk->rl, value);
+	spin_unlock(&gc->lock);
+
+	return len;
+}
+
+static ssize_t pblk_sysfs_gc_force(struct pblk *pblk, const char *page,
+				   size_t len)
+{
+	size_t c_len;
+	int force;
+
+	c_len = strcspn(page, "\n");
+	if (c_len >= len)
+		return -EINVAL;
+
+	if (kstrtouint(page, 0, &force))
+		return -EINVAL;
+
+	if (force < 0 || force > 1)
+		return -EINVAL;
+
+	pblk_gc_sysfs_force(pblk, force);
+
+	return len;
+}
+
+static struct attribute sys_write_luns = {
+	.name = "write_luns",
+	.mode = 0444,
+};
+
+static struct attribute sys_rate_limiter_attr = {
+	.name = "rate_limiter",
+	.mode = 0444,
+};
+
+static struct attribute sys_gc_state = {
+	.name = "gc_state",
+	.mode = 0444,
+};
+
+static struct attribute sys_errors_attr = {
+	.name = "errors",
+	.mode = 0444,
+};
+
+static struct attribute sys_rb_attr = {
+	.name = "write_buffer",
+	.mode = 0444,
+};
+
+static struct attribute sys_stats_ppaf_attr = {
+	.name = "ppa_format",
+	.mode = 0444,
+};
+
+static struct attribute sys_lines_attr = {
+	.name = "lines",
+	.mode = 0444,
+};
+
+static struct attribute sys_lines_info_attr = {
+	.name = "lines_info",
+	.mode = 0444,
+};
+
+static struct attribute sys_gc_force = {
+	.name = "gc_force",
+	.mode = 0200,
+};
+
+static struct attribute sys_gc_rl_max = {
+	.name = "gc_rl_max",
+	.mode = 0200,
+};
+
+#ifdef CONFIG_NVM_DEBUG
+static struct attribute sys_stats_debug_attr = {
+	.name = "stats",
+	.mode = 0444,
+};
+#endif
+
+static struct attribute *pblk_attrs[] = {
+	&sys_write_luns,
+	&sys_rate_limiter_attr,
+	&sys_errors_attr,
+	&sys_gc_state,
+	&sys_gc_force,
+	&sys_gc_rl_max,
+	&sys_rb_attr,
+	&sys_stats_ppaf_attr,
+	&sys_lines_attr,
+	&sys_lines_info_attr,
+#ifdef CONFIG_NVM_DEBUG
+	&sys_stats_debug_attr,
+#endif
+	NULL,
+};
+
+static ssize_t pblk_sysfs_show(struct kobject *kobj, struct attribute *attr,
+			       char *buf)
+{
+	struct pblk *pblk = container_of(kobj, struct pblk, kobj);
+
+	if (strcmp(attr->name, "rate_limiter") == 0)
+		return pblk_sysfs_rate_limiter(pblk, buf);
+	else if (strcmp(attr->name, "write_luns") == 0)
+		return pblk_sysfs_luns_show(pblk, buf);
+	else if (strcmp(attr->name, "gc_state") == 0)
+		return pblk_sysfs_gc_state_show(pblk, buf);
+	else if (strcmp(attr->name, "errors") == 0)
+		return pblk_sysfs_stats(pblk, buf);
+	else if (strcmp(attr->name, "write_buffer") == 0)
+		return pblk_sysfs_write_buffer(pblk, buf);
+	else if (strcmp(attr->name, "ppa_format") == 0)
+		return pblk_sysfs_ppaf(pblk, buf);
+	else if (strcmp(attr->name, "lines") == 0)
+		return pblk_sysfs_lines(pblk, buf);
+	else if (strcmp(attr->name, "lines_info") == 0)
+		return pblk_sysfs_lines_info(pblk, buf);
+#ifdef CONFIG_NVM_DEBUG
+	else if (strcmp(attr->name, "stats") == 0)
+		return pblk_sysfs_stats_debug(pblk, buf);
+#endif
+	return 0;
+}
+
+static ssize_t pblk_sysfs_store(struct kobject *kobj, struct attribute *attr,
+				const char *buf, size_t len)
+{
+	struct pblk *pblk = container_of(kobj, struct pblk, kobj);
+
+	if (strcmp(attr->name, "gc_rl_max") == 0)
+		return pblk_sysfs_rate_store(pblk, buf, len);
+	else if (strcmp(attr->name, "gc_force") == 0)
+		return pblk_sysfs_gc_force(pblk, buf, len);
+
+	return 0;
+}
+
+static const struct sysfs_ops pblk_sysfs_ops = {
+	.show = pblk_sysfs_show,
+	.store = pblk_sysfs_store,
+};
+
+static struct kobj_type pblk_ktype = {
+	.sysfs_ops	= &pblk_sysfs_ops,
+	.default_attrs	= pblk_attrs,
+};
+
+int pblk_sysfs_init(struct gendisk *tdisk)
+{
+	struct pblk *pblk = tdisk->private_data;
+	struct device *parent_dev = disk_to_dev(pblk->disk);
+	int ret;
+
+	ret = kobject_init_and_add(&pblk->kobj, &pblk_ktype,
+					kobject_get(&parent_dev->kobj),
+					"%s", "pblk");
+	if (ret) {
+		pr_err("pblk: could not register %s/pblk\n",
+						tdisk->disk_name);
+		return ret;
+	}
+
+	kobject_uevent(&pblk->kobj, KOBJ_ADD);
+	return 0;
+}
+
+void pblk_sysfs_exit(struct gendisk *tdisk)
+{
+	struct pblk *pblk = tdisk->private_data;
+
+	kobject_uevent(&pblk->kobj, KOBJ_REMOVE);
+	kobject_del(&pblk->kobj);
+	kobject_put(&pblk->kobj);
+}

drivers/lightnvm/pblk-write.c

+/*
+ * Copyright (C) 2016 CNEX Labs
+ * Initial release: Javier Gonzalez <javier@cnexlabs.com>
+ *                  Matias Bjorling <matias@cnexlabs.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * pblk-write.c - pblk's write path from write buffer to media
+ */
+
+#include "pblk.h"
+
+static void pblk_sync_line(struct pblk *pblk, struct pblk_line *line)
+{
+#ifdef CONFIG_NVM_DEBUG
+	atomic_long_inc(&pblk->sync_writes);
+#endif
+
+	/* Counter protected by rb sync lock */
+	line->left_ssecs--;
+	if (!line->left_ssecs)
+		pblk_line_run_ws(pblk, line, NULL, pblk_line_close_ws);
+}
+
+static unsigned long pblk_end_w_bio(struct pblk *pblk, struct nvm_rq *rqd,
+				    struct pblk_c_ctx *c_ctx)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct bio *original_bio;
+	unsigned long ret;
+	int i;
+
+	for (i = 0; i < c_ctx->nr_valid; i++) {
+		struct pblk_w_ctx *w_ctx;
+		struct ppa_addr p;
+		struct pblk_line *line;
+
+		w_ctx = pblk_rb_w_ctx(&pblk->rwb, c_ctx->sentry + i);
+
+		p = rqd->ppa_list[i];
+		line = &pblk->lines[pblk_dev_ppa_to_line(p)];
+		pblk_sync_line(pblk, line);
+
+		while ((original_bio = bio_list_pop(&w_ctx->bios)))
+			bio_endio(original_bio);
+	}
+
+#ifdef CONFIG_NVM_DEBUG
+	atomic_long_add(c_ctx->nr_valid, &pblk->compl_writes);
+#endif
+
+	ret = pblk_rb_sync_advance(&pblk->rwb, c_ctx->nr_valid);
+
+	if (rqd->meta_list)
+		nvm_dev_dma_free(dev->parent, rqd->meta_list,
+							rqd->dma_meta_list);
+
+	bio_put(rqd->bio);
+	pblk_free_rqd(pblk, rqd, WRITE);
+
+	return ret;
+}
+
+static unsigned long pblk_end_queued_w_bio(struct pblk *pblk,
+					   struct nvm_rq *rqd,
+					   struct pblk_c_ctx *c_ctx)
+{
+	list_del(&c_ctx->list);
+	return pblk_end_w_bio(pblk, rqd, c_ctx);
+}
+
+static void pblk_complete_write(struct pblk *pblk, struct nvm_rq *rqd,
+				struct pblk_c_ctx *c_ctx)
+{
+	struct pblk_c_ctx *c, *r;
+	unsigned long flags;
+	unsigned long pos;
+
+#ifdef CONFIG_NVM_DEBUG
+	atomic_long_sub(c_ctx->nr_valid, &pblk->inflight_writes);
+#endif
+
+	pblk_up_rq(pblk, rqd->ppa_list, rqd->nr_ppas, c_ctx->lun_bitmap);
+
+	pos = pblk_rb_sync_init(&pblk->rwb, &flags);
+	if (pos == c_ctx->sentry) {
+		pos = pblk_end_w_bio(pblk, rqd, c_ctx);
+
+retry:
+		list_for_each_entry_safe(c, r, &pblk->compl_list, list) {
+			rqd = nvm_rq_from_c_ctx(c);
+			if (c->sentry == pos) {
+				pos = pblk_end_queued_w_bio(pblk, rqd, c);
+				goto retry;
+			}
+		}
+	} else {
+		WARN_ON(nvm_rq_from_c_ctx(c_ctx) != rqd);
+		list_add_tail(&c_ctx->list, &pblk->compl_list);
+	}
+	pblk_rb_sync_end(&pblk->rwb, &flags);
+}
+
+/* When a write fails, we are not sure whether the block has grown bad or a page
+ * range is more susceptible to write errors. If a high number of pages fail, we
+ * assume that the block is bad and we mark it accordingly. In all cases, we
+ * remap and resubmit the failed entries as fast as possible; if a flush is
+ * waiting on a completion, the whole stack would stall otherwise.
+ */
+static void pblk_end_w_fail(struct pblk *pblk, struct nvm_rq *rqd)
+{
+	void *comp_bits = &rqd->ppa_status;
+	struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
+	struct pblk_rec_ctx *recovery;
+	struct ppa_addr *ppa_list = rqd->ppa_list;
+	int nr_ppas = rqd->nr_ppas;
+	unsigned int c_entries;
+	int bit, ret;
+
+	if (unlikely(nr_ppas == 1))
+		ppa_list = &rqd->ppa_addr;
+
+	recovery = mempool_alloc(pblk->rec_pool, GFP_ATOMIC);
+	if (!recovery) {
+		pr_err("pblk: could not allocate recovery context\n");
+		return;
+	}
+	INIT_LIST_HEAD(&recovery->failed);
+
+	bit = -1;
+	while ((bit = find_next_bit(comp_bits, nr_ppas, bit + 1)) < nr_ppas) {
+		struct pblk_rb_entry *entry;
+		struct ppa_addr ppa;
+
+		/* Logic error */
+		if (bit > c_ctx->nr_valid) {
+			WARN_ON_ONCE("pblk: corrupted write request\n");
+			goto out;
+		}
+
+		ppa = ppa_list[bit];
+		entry = pblk_rb_sync_scan_entry(&pblk->rwb, &ppa);
+		if (!entry) {
+			pr_err("pblk: could not scan entry on write failure\n");
+			goto out;
+		}
+
+		/* The list is filled first and emptied afterwards. No need for
+		 * protecting it with a lock
+		 */
+		list_add_tail(&entry->index, &recovery->failed);
+	}
+
+	c_entries = find_first_bit(comp_bits, nr_ppas);
+	ret = pblk_recov_setup_rq(pblk, c_ctx, recovery, comp_bits, c_entries);
+	if (ret) {
+		pr_err("pblk: could not recover from write failure\n");
+		goto out;
+	}
+
+	INIT_WORK(&recovery->ws_rec, pblk_submit_rec);
+	queue_work(pblk->kw_wq, &recovery->ws_rec);
+
+out:
+	pblk_complete_write(pblk, rqd, c_ctx);
+}
+
+static void pblk_end_io_write(struct nvm_rq *rqd)
+{
+	struct pblk *pblk = rqd->private;
+	struct pblk_c_ctx *c_ctx = nvm_rq_to_pdu(rqd);
+
+	if (rqd->error) {
+		pblk_log_write_err(pblk, rqd);
+		return pblk_end_w_fail(pblk, rqd);
+	}
+#ifdef CONFIG_NVM_DEBUG
+	else
+		WARN_ONCE(rqd->bio->bi_error, "pblk: corrupted write error\n");
+#endif
+
+	pblk_complete_write(pblk, rqd, c_ctx);
+}
+
+static int pblk_alloc_w_rq(struct pblk *pblk, struct nvm_rq *rqd,
+			   unsigned int nr_secs)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+
+	/* Setup write request */
+	rqd->opcode = NVM_OP_PWRITE;
+	rqd->nr_ppas = nr_secs;
+	rqd->flags = pblk_set_progr_mode(pblk, WRITE);
+	rqd->private = pblk;
+	rqd->end_io = pblk_end_io_write;
+
+	rqd->meta_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
+							&rqd->dma_meta_list);
+	if (!rqd->meta_list)
+		return -ENOMEM;
+
+	if (unlikely(nr_secs == 1))
+		return 0;
+
+	rqd->ppa_list = rqd->meta_list + pblk_dma_meta_size;
+	rqd->dma_ppa_list = rqd->dma_meta_list + pblk_dma_meta_size;
+
+	return 0;
+}
+
+static int pblk_setup_w_rq(struct pblk *pblk, struct nvm_rq *rqd,
+			   struct pblk_c_ctx *c_ctx)
+{
+	struct pblk_line_meta *lm = &pblk->lm;
+	struct pblk_line *e_line = pblk_line_get_data_next(pblk);
+	struct ppa_addr erase_ppa;
+	unsigned int valid = c_ctx->nr_valid;
+	unsigned int padded = c_ctx->nr_padded;
+	unsigned int nr_secs = valid + padded;
+	unsigned long *lun_bitmap;
+	int ret = 0;
+
+	lun_bitmap = kzalloc(lm->lun_bitmap_len, GFP_KERNEL);
+	if (!lun_bitmap) {
+		ret = -ENOMEM;
+		goto out;
+	}
+	c_ctx->lun_bitmap = lun_bitmap;
+
+	ret = pblk_alloc_w_rq(pblk, rqd, nr_secs);
+	if (ret) {
+		kfree(lun_bitmap);
+		goto out;
+	}
+
+	ppa_set_empty(&erase_ppa);
+	if (likely(!e_line || !e_line->left_eblks))
+		pblk_map_rq(pblk, rqd, c_ctx->sentry, lun_bitmap, valid, 0);
+	else
+		pblk_map_erase_rq(pblk, rqd, c_ctx->sentry, lun_bitmap,
+							valid, &erase_ppa);
+
+out:
+	if (unlikely(e_line && !ppa_empty(erase_ppa))) {
+		if (pblk_blk_erase_async(pblk, erase_ppa)) {
+			struct nvm_tgt_dev *dev = pblk->dev;
+			struct nvm_geo *geo = &dev->geo;
+			int bit;
+
+			e_line->left_eblks++;
+			bit = erase_ppa.g.lun * geo->nr_chnls + erase_ppa.g.ch;
+			WARN_ON(!test_and_clear_bit(bit, e_line->erase_bitmap));
+			up(&pblk->erase_sem);
+		}
+	}
+
+	return ret;
+}
+
+int pblk_setup_w_rec_rq(struct pblk *pblk, struct nvm_rq *rqd,
+			struct pblk_c_ctx *c_ctx)
+{
+	struct pblk_line_meta *lm = &pblk->lm;
+	unsigned long *lun_bitmap;
+	int ret;
+
+	lun_bitmap = kzalloc(lm->lun_bitmap_len, GFP_KERNEL);
+	if (!lun_bitmap)
+		return -ENOMEM;
+
+	c_ctx->lun_bitmap = lun_bitmap;
+
+	ret = pblk_alloc_w_rq(pblk, rqd, rqd->nr_ppas);
+	if (ret)
+		return ret;
+
+	pblk_map_rq(pblk, rqd, c_ctx->sentry, lun_bitmap, c_ctx->nr_valid, 0);
+
+	rqd->ppa_status = (u64)0;
+	rqd->flags = pblk_set_progr_mode(pblk, WRITE);
+
+	return ret;
+}
+
+static int pblk_calc_secs_to_sync(struct pblk *pblk, unsigned int secs_avail,
+				  unsigned int secs_to_flush)
+{
+	int secs_to_sync;
+
+	secs_to_sync = pblk_calc_secs(pblk, secs_avail, secs_to_flush);
+
+#ifdef CONFIG_NVM_DEBUG
+	if ((!secs_to_sync && secs_to_flush)
+			|| (secs_to_sync < 0)
+			|| (secs_to_sync > secs_avail && !secs_to_flush)) {
+		pr_err("pblk: bad sector calculation (a:%d,s:%d,f:%d)\n",
+				secs_avail, secs_to_sync, secs_to_flush);
+	}
+#endif
+
+	return secs_to_sync;
+}
+
+static int pblk_submit_write(struct pblk *pblk)
+{
+	struct bio *bio;
+	struct nvm_rq *rqd;
+	struct pblk_c_ctx *c_ctx;
+	unsigned int pgs_read;
+	unsigned int secs_avail, secs_to_sync, secs_to_com;
+	unsigned int secs_to_flush;
+	unsigned long pos;
+	int err;
+
+	/* If there are no sectors in the cache, flushes (bios without data)
+	 * will be cleared on the cache threads
+	 */
+	secs_avail = pblk_rb_read_count(&pblk->rwb);
+	if (!secs_avail)
+		return 1;
+
+	secs_to_flush = pblk_rb_sync_point_count(&pblk->rwb);
+	if (!secs_to_flush && secs_avail < pblk->min_write_pgs)
+		return 1;
+
+	rqd = pblk_alloc_rqd(pblk, WRITE);
+	if (IS_ERR(rqd)) {
+		pr_err("pblk: cannot allocate write req.\n");
+		return 1;
+	}
+	c_ctx = nvm_rq_to_pdu(rqd);
+
+	bio = bio_alloc(GFP_KERNEL, pblk->max_write_pgs);
+	if (!bio) {
+		pr_err("pblk: cannot allocate write bio\n");
+		goto fail_free_rqd;
+	}
+	bio->bi_iter.bi_sector = 0; /* internal bio */
+	bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
+	rqd->bio = bio;
+
+	secs_to_sync = pblk_calc_secs_to_sync(pblk, secs_avail, secs_to_flush);
+	if (secs_to_sync > pblk->max_write_pgs) {
+		pr_err("pblk: bad buffer sync calculation\n");
+		goto fail_put_bio;
+	}
+
+	secs_to_com = (secs_to_sync > secs_avail) ? secs_avail : secs_to_sync;
+	pos = pblk_rb_read_commit(&pblk->rwb, secs_to_com);
+
+	pgs_read = pblk_rb_read_to_bio(&pblk->rwb, bio, c_ctx, pos,
+						secs_to_sync, secs_avail);
+	if (!pgs_read) {
+		pr_err("pblk: corrupted write bio\n");
+		goto fail_put_bio;
+	}
+
+	if (c_ctx->nr_padded)
+		if (pblk_bio_add_pages(pblk, bio, GFP_KERNEL, c_ctx->nr_padded))
+			goto fail_put_bio;
+
+	/* Assign lbas to ppas and populate request structure */
+	err = pblk_setup_w_rq(pblk, rqd, c_ctx);
+	if (err) {
+		pr_err("pblk: could not setup write request\n");
+		goto fail_free_bio;
+	}
+
+	err = pblk_submit_io(pblk, rqd);
+	if (err) {
+		pr_err("pblk: I/O submission failed: %d\n", err);
+		goto fail_free_bio;
+	}
+
+#ifdef CONFIG_NVM_DEBUG
+	atomic_long_add(secs_to_sync, &pblk->sub_writes);
+#endif
+
+	return 0;
+
+fail_free_bio:
+	if (c_ctx->nr_padded)
+		pblk_bio_free_pages(pblk, bio, secs_to_sync, c_ctx->nr_padded);
+fail_put_bio:
+	bio_put(bio);
+fail_free_rqd:
+	pblk_free_rqd(pblk, rqd, WRITE);
+
+	return 1;
+}
+
+int pblk_write_ts(void *data)
+{
+	struct pblk *pblk = data;
+
+	while (!kthread_should_stop()) {
+		if (!pblk_submit_write(pblk))
+			continue;
+		set_current_state(TASK_INTERRUPTIBLE);
+		io_schedule();
+	}
+
+	return 0;
+}

drivers/lightnvm/pblk.h

+/*
+ * Copyright (C) 2015 IT University of Copenhagen (rrpc.h)
+ * Copyright (C) 2016 CNEX Labs
+ * Initial release: Matias Bjorling <matias@cnexlabs.com>
+ * Write buffering: Javier Gonzalez <javier@cnexlabs.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * Implementation of a Physical Block-device target for Open-channel SSDs.
+ *
+ */
+
+#ifndef PBLK_H_
+#define PBLK_H_
+
+#include <linux/blkdev.h>
+#include <linux/blk-mq.h>
+#include <linux/bio.h>
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/vmalloc.h>
+#include <linux/crc32.h>
+#include <linux/uuid.h>
+
+#include <linux/lightnvm.h>
+
+/* Run only GC if less than 1/X blocks are free */
+#define GC_LIMIT_INVERSE 5
+#define GC_TIME_MSECS 1000
+
+#define PBLK_SECTOR (512)
+#define PBLK_EXPOSED_PAGE_SIZE (4096)
+#define PBLK_MAX_REQ_ADDRS (64)
+#define PBLK_MAX_REQ_ADDRS_PW (6)
+
+#define PBLK_CACHE_NAME_LEN (DISK_NAME_LEN + 16)
+
+#define PBLK_COMMAND_TIMEOUT_MS 30000
+
+/* Max 512 LUNs per device */
+#define PBLK_MAX_LUNS_BITMAP (4)
+
+#define NR_PHY_IN_LOG (PBLK_EXPOSED_PAGE_SIZE / PBLK_SECTOR)
+
+#define pblk_for_each_lun(pblk, rlun, i) \
+		for ((i) = 0, rlun = &(pblk)->luns[0]; \
+			(i) < (pblk)->nr_luns; (i)++, rlun = &(pblk)->luns[(i)])
+
+#define ERASE 2 /* READ = 0, WRITE = 1 */
+
+enum {
+	/* IO Types */
+	PBLK_IOTYPE_USER	= 1 << 0,
+	PBLK_IOTYPE_GC		= 1 << 1,
+
+	/* Write buffer flags */
+	PBLK_FLUSH_ENTRY	= 1 << 2,
+	PBLK_WRITTEN_DATA	= 1 << 3,
+	PBLK_SUBMITTED_ENTRY	= 1 << 4,
+	PBLK_WRITABLE_ENTRY	= 1 << 5,
+};
+
+enum {
+	PBLK_BLK_ST_OPEN =	0x1,
+	PBLK_BLK_ST_CLOSED =	0x2,
+};
+
+/* The number of GC lists and the rate-limiter states go together. This way the
+ * rate-limiter can dictate how much GC is needed based on resource utilization.
+ */
+#define PBLK_NR_GC_LISTS 3
+#define PBLK_MAX_GC_JOBS 32
+
+enum {
+	PBLK_RL_HIGH = 1,
+	PBLK_RL_MID = 2,
+	PBLK_RL_LOW = 3,
+};
+
+struct pblk_sec_meta {
+	u64 reserved;
+	__le64 lba;
+};
+
+#define pblk_dma_meta_size (sizeof(struct pblk_sec_meta) * PBLK_MAX_REQ_ADDRS)
+
+/* write completion context */
+struct pblk_c_ctx {
+	struct list_head list;		/* Head for out-of-order completion */
+
+	unsigned long *lun_bitmap;	/* Luns used on current request */
+	unsigned int sentry;
+	unsigned int nr_valid;
+	unsigned int nr_padded;
+};
+
+/* Read context */
+struct pblk_r_ctx {
+	struct bio *orig_bio;
+};
+
+/* Recovery context */
+struct pblk_rec_ctx {
+	struct pblk *pblk;
+	struct nvm_rq *rqd;
+	struct list_head failed;
+	struct work_struct ws_rec;
+};
+
+/* Write context */
+struct pblk_w_ctx {
+	struct bio_list bios;		/* Original bios - used for completion
+					 * in REQ_FUA, REQ_FLUSH case
+					 */
+	sector_t lba;			/* Logic addr. associated with entry */
+	struct ppa_addr ppa;		/* Physic addr. associated with entry */
+	int flags;			/* Write context flags */
+};
+
+struct pblk_rb_entry {
+	struct ppa_addr cacheline;	/* Cacheline for this entry */
+	void *data;			/* Pointer to data on this entry */
+	struct pblk_w_ctx w_ctx;	/* Context for this entry */
+	struct list_head index;		/* List head to enable indexes */
+};
+
+#define EMPTY_ENTRY (~0U)
+
+struct pblk_rb_pages {
+	struct page *pages;
+	int order;
+	struct list_head list;
+};
+
+struct pblk_rb {
+	struct pblk_rb_entry *entries;	/* Ring buffer entries */
+	unsigned int mem;		/* Write offset - points to next
+					 * writable entry in memory
+					 */
+	unsigned int subm;		/* Read offset - points to last entry
+					 * that has been submitted to the media
+					 * to be persisted
+					 */
+	unsigned int sync;		/* Synced - backpointer that signals
+					 * the last submitted entry that has
+					 * been successfully persisted to media
+					 */
+	unsigned int sync_point;	/* Sync point - last entry that must be
+					 * flushed to the media. Used with
+					 * REQ_FLUSH and REQ_FUA
+					 */
+	unsigned int l2p_update;	/* l2p update point - next entry for
+					 * which l2p mapping will be updated to
+					 * contain a device ppa address (instead
+					 * of a cacheline
+					 */
+	unsigned int nr_entries;	/* Number of entries in write buffer -
+					 * must be a power of two
+					 */
+	unsigned int seg_size;		/* Size of the data segments being
+					 * stored on each entry. Typically this
+					 * will be 4KB
+					 */
+
+	struct list_head pages;		/* List of data pages */
+
+	spinlock_t w_lock;		/* Write lock */
+	spinlock_t s_lock;		/* Sync lock */
+
+#ifdef CONFIG_NVM_DEBUG
+	atomic_t inflight_sync_point;	/* Not served REQ_FLUSH | REQ_FUA */
+#endif
+};
+
+#define PBLK_RECOVERY_SECTORS 16
+
+struct pblk_lun {
+	struct ppa_addr bppa;
+
+	u8 *bb_list;			/* Bad block list for LUN. Only used on
+					 * bring up. Bad blocks are managed
+					 * within lines on run-time.
+					 */
+
+	struct semaphore wr_sem;
+};
+
+struct pblk_gc_rq {
+	struct pblk_line *line;
+	void *data;
+	u64 *lba_list;
+	int nr_secs;
+	int secs_to_gc;
+	struct list_head list;
+};
+
+struct pblk_gc {
+	int gc_active;
+	int gc_enabled;
+	int gc_forced;
+	int gc_jobs_active;
+	atomic_t inflight_gc;
+
+	struct task_struct *gc_ts;
+	struct task_struct *gc_writer_ts;
+	struct workqueue_struct *gc_reader_wq;
+	struct timer_list gc_timer;
+
+	int w_entries;
+	struct list_head w_list;
+
+	spinlock_t lock;
+	spinlock_t w_lock;
+};
+
+struct pblk_rl {
+	unsigned int high;	/* Upper threshold for rate limiter (free run -
+				 * user I/O rate limiter
+				 */
+	unsigned int low;	/* Lower threshold for rate limiter (user I/O
+				 * rate limiter - stall)
+				 */
+	unsigned int high_pw;	/* High rounded up as a power of 2 */
+
+#define PBLK_USER_HIGH_THRS 2	/* Begin write limit at 50 percent
+				 * available blks
+				 */
+#define PBLK_USER_LOW_THRS 20	/* Aggressive GC at 5% available blocks */
+
+	int rb_windows_pw;	/* Number of rate windows in the write buffer
+				 * given as a power-of-2. This guarantees that
+				 * when user I/O is being rate limited, there
+				 * will be reserved enough space for the GC to
+				 * place its payload. A window is of
+				 * pblk->max_write_pgs size, which in NVMe is
+				 * 64, i.e., 256kb.
+				 */
+	int rb_budget;		/* Total number of entries available for I/O */
+	int rb_user_max;	/* Max buffer entries available for user I/O */
+	atomic_t rb_user_cnt;	/* User I/O buffer counter */
+	int rb_gc_max;		/* Max buffer entries available for GC I/O */
+	int rb_gc_rsv;		/* Reserved buffer entries for GC I/O */
+	int rb_state;		/* Rate-limiter current state */
+	atomic_t rb_gc_cnt;	/* GC I/O buffer counter */
+
+	int rb_user_active;
+	struct timer_list u_timer;
+
+	unsigned long long nr_secs;
+	unsigned long total_blocks;
+	atomic_t free_blocks;
+};
+
+#define PBLK_LINE_NR_LUN_BITMAP 2
+#define PBLK_LINE_NR_SEC_BITMAP 2
+#define PBLK_LINE_EMPTY (~0U)
+
+enum {
+	/* Line Types */
+	PBLK_LINETYPE_FREE = 0,
+	PBLK_LINETYPE_LOG = 1,
+	PBLK_LINETYPE_DATA = 2,
+
+	/* Line state */
+	PBLK_LINESTATE_FREE = 10,
+	PBLK_LINESTATE_OPEN = 11,
+	PBLK_LINESTATE_CLOSED = 12,
+	PBLK_LINESTATE_GC = 13,
+	PBLK_LINESTATE_BAD = 14,
+	PBLK_LINESTATE_CORRUPT = 15,
+
+	/* GC group */
+	PBLK_LINEGC_NONE = 20,
+	PBLK_LINEGC_EMPTY = 21,
+	PBLK_LINEGC_LOW = 22,
+	PBLK_LINEGC_MID = 23,
+	PBLK_LINEGC_HIGH = 24,
+	PBLK_LINEGC_FULL = 25,
+};
+
+#define PBLK_MAGIC 0x70626c6b /*pblk*/
+
+struct line_header {
+	__le32 crc;
+	__le32 identifier;	/* pblk identifier */
+	__u8 uuid[16];		/* instance uuid */
+	__le16 type;		/* line type */
+	__le16 version;		/* type version */
+	__le32 id;		/* line id for current line */
+};
+
+struct line_smeta {
+	struct line_header header;
+
+	__le32 crc;		/* Full structure including struct crc */
+	/* Previous line metadata */
+	__le32 prev_id;		/* Line id for previous line */
+
+	/* Current line metadata */
+	__le64 seq_nr;		/* Sequence number for current line */
+
+	/* Active writers */
+	__le32 window_wr_lun;	/* Number of parallel LUNs to write */
+
+	__le32 rsvd[2];
+};
+
+/*
+ * Metadata Layout:
+ *	1. struct pblk_emeta
+ *	2. nr_lbas u64 forming lba list
+ *	3. nr_lines (all) u32 valid sector count (vsc) (~0U: non-alloc line)
+ *	4. nr_luns bits (u64 format) forming line bad block bitmap
+ *
+ *	3. and 4. will be part of FTL log
+ */
+struct line_emeta {
+	struct line_header header;
+
+	__le32 crc;		/* Full structure including struct crc */
+
+	/* Previous line metadata */
+	__le32 prev_id;		/* Line id for prev line */
+
+	/* Current line metadata */
+	__le64 seq_nr;		/* Sequence number for current line */
+
+	/* Active writers */
+	__le32 window_wr_lun;	/* Number of parallel LUNs to write */
+
+	/* Bookkeeping for recovery */
+	__le32 next_id;		/* Line id for next line */
+	__le64 nr_lbas;		/* Number of lbas mapped in line */
+	__le64 nr_valid_lbas;	/* Number of valid lbas mapped in line */
+};
+
+struct pblk_line {
+	struct pblk *pblk;
+	unsigned int id;		/* Line number corresponds to the
+					 * block line
+					 */
+	unsigned int seq_nr;		/* Unique line sequence number */
+
+	int state;			/* PBLK_LINESTATE_X */
+	int type;			/* PBLK_LINETYPE_X */
+	int gc_group;			/* PBLK_LINEGC_X */
+	struct list_head list;		/* Free, GC lists */
+
+	unsigned long *lun_bitmap;	/* Bitmap for LUNs mapped in line */
+
+	struct line_smeta *smeta;	/* Start metadata */
+	struct line_emeta *emeta;	/* End metadata */
+	int meta_line;			/* Metadata line id */
+	u64 smeta_ssec;			/* Sector where smeta starts */
+	u64 emeta_ssec;			/* Sector where emeta starts */
+
+	unsigned int sec_in_line;	/* Number of usable secs in line */
+
+	unsigned int blk_in_line;	/* Number of good blocks in line */
+	unsigned long *blk_bitmap;	/* Bitmap for valid/invalid blocks */
+	unsigned long *erase_bitmap;	/* Bitmap for erased blocks */
+
+	unsigned long *map_bitmap;	/* Bitmap for mapped sectors in line */
+	unsigned long *invalid_bitmap;	/* Bitmap for invalid sectors in line */
+
+	int left_eblks;			/* Blocks left for erasing */
+	atomic_t left_seblks;		/* Blocks left for sync erasing */
+
+	int left_msecs;			/* Sectors left for mapping */
+	int left_ssecs;			/* Sectors left to sync */
+	unsigned int cur_sec;		/* Sector map pointer */
+	unsigned int vsc;		/* Valid sector count in line */
+
+	struct kref ref;		/* Write buffer L2P references */
+
+	spinlock_t lock;		/* Necessary for invalid_bitmap only */
+};
+
+#define PBLK_DATA_LINES 2
+
+enum{
+	PBLK_KMALLOC_META = 1,
+	PBLK_VMALLOC_META = 2,
+};
+
+struct pblk_line_metadata {
+	void *meta;
+};
+
+struct pblk_line_mgmt {
+	int nr_lines;			/* Total number of full lines */
+	int nr_free_lines;		/* Number of full lines in free list */
+
+	/* Free lists - use free_lock */
+	struct list_head free_list;	/* Full lines ready to use */
+	struct list_head corrupt_list;	/* Full lines corrupted */
+	struct list_head bad_list;	/* Full lines bad */
+
+	/* GC lists - use gc_lock */
+	struct list_head *gc_lists[PBLK_NR_GC_LISTS];
+	struct list_head gc_high_list;	/* Full lines ready to GC, high isc */
+	struct list_head gc_mid_list;	/* Full lines ready to GC, mid isc */
+	struct list_head gc_low_list;	/* Full lines ready to GC, low isc */
+
+	struct list_head gc_full_list;	/* Full lines ready to GC, no valid */
+	struct list_head gc_empty_list;	/* Full lines close, all valid */
+
+	struct pblk_line *log_line;	/* Current FTL log line */
+	struct pblk_line *data_line;	/* Current data line */
+	struct pblk_line *log_next;	/* Next FTL log line */
+	struct pblk_line *data_next;	/* Next data line */
+
+	/* Metadata allocation type: VMALLOC | KMALLOC */
+	int smeta_alloc_type;
+	int emeta_alloc_type;
+
+	/* Pre-allocated metadata for data lines */
+	struct pblk_line_metadata sline_meta[PBLK_DATA_LINES];
+	struct pblk_line_metadata eline_meta[PBLK_DATA_LINES];
+	unsigned long meta_bitmap;
+
+	/* Helpers for fast bitmap calculations */
+	unsigned long *bb_template;
+	unsigned long *bb_aux;
+
+	unsigned long d_seq_nr;		/* Data line unique sequence number */
+	unsigned long l_seq_nr;		/* Log line unique sequence number */
+
+	spinlock_t free_lock;
+	spinlock_t gc_lock;
+};
+
+struct pblk_line_meta {
+	unsigned int smeta_len;		/* Total length for smeta */
+	unsigned int smeta_sec;		/* Sectors needed for smeta*/
+	unsigned int emeta_len;		/* Total length for emeta */
+	unsigned int emeta_sec;		/* Sectors needed for emeta*/
+	unsigned int emeta_bb;		/* Boundary for bb that affects emeta */
+	unsigned int sec_bitmap_len;	/* Length for sector bitmap in line */
+	unsigned int blk_bitmap_len;	/* Length for block bitmap in line */
+	unsigned int lun_bitmap_len;	/* Length for lun bitmap in line */
+
+	unsigned int blk_per_line;	/* Number of blocks in a full line */
+	unsigned int sec_per_line;	/* Number of sectors in a line */
+	unsigned int min_blk_line;	/* Min. number of good blocks in line */
+
+	unsigned int mid_thrs;		/* Threshold for GC mid list */
+	unsigned int high_thrs;		/* Threshold for GC high list */
+};
+
+struct pblk_addr_format {
+	u64	ch_mask;
+	u64	lun_mask;
+	u64	pln_mask;
+	u64	blk_mask;
+	u64	pg_mask;
+	u64	sec_mask;
+	u8	ch_offset;
+	u8	lun_offset;
+	u8	pln_offset;
+	u8	blk_offset;
+	u8	pg_offset;
+	u8	sec_offset;
+};
+
+struct pblk {
+	struct nvm_tgt_dev *dev;
+	struct gendisk *disk;
+
+	struct kobject kobj;
+
+	struct pblk_lun *luns;
+
+	struct pblk_line *lines;		/* Line array */
+	struct pblk_line_mgmt l_mg;		/* Line management */
+	struct pblk_line_meta lm;		/* Line metadata */
+
+	int ppaf_bitsize;
+	struct pblk_addr_format ppaf;
+
+	struct pblk_rb rwb;
+
+	int min_write_pgs; /* Minimum amount of pages required by controller */
+	int max_write_pgs; /* Maximum amount of pages supported by controller */
+	int pgs_in_buffer; /* Number of pages that need to be held in buffer to
+			    * guarantee successful reads.
+			    */
+
+	sector_t capacity; /* Device capacity when bad blocks are subtracted */
+	int over_pct;      /* Percentage of device used for over-provisioning */
+
+	/* pblk provisioning values. Used by rate limiter */
+	struct pblk_rl rl;
+
+	struct semaphore erase_sem;
+
+	unsigned char instance_uuid[16];
+#ifdef CONFIG_NVM_DEBUG
+	/* All debug counters apply to 4kb sector I/Os */
+	atomic_long_t inflight_writes;	/* Inflight writes (user and gc) */
+	atomic_long_t padded_writes;	/* Sectors padded due to flush/fua */
+	atomic_long_t padded_wb;	/* Sectors padded in write buffer */
+	atomic_long_t nr_flush;		/* Number of flush/fua I/O */
+	atomic_long_t req_writes;	/* Sectors stored on write buffer */
+	atomic_long_t sub_writes;	/* Sectors submitted from buffer */
+	atomic_long_t sync_writes;	/* Sectors synced to media */
+	atomic_long_t compl_writes;	/* Sectors completed in write bio */
+	atomic_long_t inflight_reads;	/* Inflight sector read requests */
+	atomic_long_t sync_reads;	/* Completed sector read requests */
+	atomic_long_t recov_writes;	/* Sectors submitted from recovery */
+	atomic_long_t recov_gc_writes;	/* Sectors submitted from write GC */
+	atomic_long_t recov_gc_reads;	/* Sectors submitted from read GC */
+#endif
+
+	spinlock_t lock;
+
+	atomic_long_t read_failed;
+	atomic_long_t read_empty;
+	atomic_long_t read_high_ecc;
+	atomic_long_t read_failed_gc;
+	atomic_long_t write_failed;
+	atomic_long_t erase_failed;
+
+	struct task_struct *writer_ts;
+
+	/* Simple translation map of logical addresses to physical addresses.
+	 * The logical addresses is known by the host system, while the physical
+	 * addresses are used when writing to the disk block device.
+	 */
+	unsigned char *trans_map;
+	spinlock_t trans_lock;
+
+	struct list_head compl_list;
+
+	mempool_t *page_pool;
+	mempool_t *line_ws_pool;
+	mempool_t *rec_pool;
+	mempool_t *r_rq_pool;
+	mempool_t *w_rq_pool;
+	mempool_t *line_meta_pool;
+
+	struct workqueue_struct *kw_wq;
+	struct timer_list wtimer;
+
+	struct pblk_gc gc;
+};
+
+struct pblk_line_ws {
+	struct pblk *pblk;
+	struct pblk_line *line;
+	void *priv;
+	struct work_struct ws;
+};
+
+#define pblk_r_rq_size (sizeof(struct nvm_rq) + sizeof(struct pblk_r_ctx))
+#define pblk_w_rq_size (sizeof(struct nvm_rq) + sizeof(struct pblk_c_ctx))
+
+/*
+ * pblk ring buffer operations
+ */
+int pblk_rb_init(struct pblk_rb *rb, struct pblk_rb_entry *rb_entry_base,
+		 unsigned int power_size, unsigned int power_seg_sz);
+unsigned int pblk_rb_calculate_size(unsigned int nr_entries);
+void *pblk_rb_entries_ref(struct pblk_rb *rb);
+int pblk_rb_may_write_user(struct pblk_rb *rb, struct bio *bio,
+			   unsigned int nr_entries, unsigned int *pos);
+int pblk_rb_may_write_gc(struct pblk_rb *rb, unsigned int nr_entries,
+			 unsigned int *pos);
+void pblk_rb_write_entry_user(struct pblk_rb *rb, void *data,
+			      struct pblk_w_ctx w_ctx, unsigned int pos);
+void pblk_rb_write_entry_gc(struct pblk_rb *rb, void *data,
+			    struct pblk_w_ctx w_ctx, struct pblk_line *gc_line,
+			    unsigned int pos);
+struct pblk_w_ctx *pblk_rb_w_ctx(struct pblk_rb *rb, unsigned int pos);
+
+void pblk_rb_sync_l2p(struct pblk_rb *rb);
+unsigned int pblk_rb_read_to_bio(struct pblk_rb *rb, struct bio *bio,
+				 struct pblk_c_ctx *c_ctx,
+				 unsigned int pos,
+				 unsigned int nr_entries,
+				 unsigned int count);
+unsigned int pblk_rb_read_to_bio_list(struct pblk_rb *rb, struct bio *bio,
+				      struct list_head *list,
+				      unsigned int max);
+int pblk_rb_copy_to_bio(struct pblk_rb *rb, struct bio *bio, sector_t lba,
+			u64 pos, int bio_iter);
+unsigned int pblk_rb_read_commit(struct pblk_rb *rb, unsigned int entries);
+
+unsigned int pblk_rb_sync_init(struct pblk_rb *rb, unsigned long *flags);
+unsigned int pblk_rb_sync_advance(struct pblk_rb *rb, unsigned int nr_entries);
+struct pblk_rb_entry *pblk_rb_sync_scan_entry(struct pblk_rb *rb,
+					      struct ppa_addr *ppa);
+void pblk_rb_sync_end(struct pblk_rb *rb, unsigned long *flags);
+unsigned int pblk_rb_sync_point_count(struct pblk_rb *rb);
+
+unsigned int pblk_rb_read_count(struct pblk_rb *rb);
+unsigned int pblk_rb_wrap_pos(struct pblk_rb *rb, unsigned int pos);
+
+int pblk_rb_tear_down_check(struct pblk_rb *rb);
+int pblk_rb_pos_oob(struct pblk_rb *rb, u64 pos);
+void pblk_rb_data_free(struct pblk_rb *rb);
+ssize_t pblk_rb_sysfs(struct pblk_rb *rb, char *buf);
+
+/*
+ * pblk core
+ */
+struct nvm_rq *pblk_alloc_rqd(struct pblk *pblk, int rw);
+int pblk_setup_w_rec_rq(struct pblk *pblk, struct nvm_rq *rqd,
+			struct pblk_c_ctx *c_ctx);
+void pblk_free_rqd(struct pblk *pblk, struct nvm_rq *rqd, int rw);
+void pblk_flush_writer(struct pblk *pblk);
+struct ppa_addr pblk_get_lba_map(struct pblk *pblk, sector_t lba);
+void pblk_discard(struct pblk *pblk, struct bio *bio);
+void pblk_log_write_err(struct pblk *pblk, struct nvm_rq *rqd);
+void pblk_log_read_err(struct pblk *pblk, struct nvm_rq *rqd);
+int pblk_submit_io(struct pblk *pblk, struct nvm_rq *rqd);
+struct bio *pblk_bio_map_addr(struct pblk *pblk, void *data,
+			      unsigned int nr_secs, unsigned int len,
+			      gfp_t gfp_mask);
+struct pblk_line *pblk_line_get(struct pblk *pblk);
+struct pblk_line *pblk_line_get_first_data(struct pblk *pblk);
+struct pblk_line *pblk_line_replace_data(struct pblk *pblk);
+int pblk_line_recov_alloc(struct pblk *pblk, struct pblk_line *line);
+void pblk_line_recov_close(struct pblk *pblk, struct pblk_line *line);
+struct pblk_line *pblk_line_get_data(struct pblk *pblk);
+struct pblk_line *pblk_line_get_data_next(struct pblk *pblk);
+int pblk_line_erase(struct pblk *pblk, struct pblk_line *line);
+int pblk_line_is_full(struct pblk_line *line);
+void pblk_line_free(struct pblk *pblk, struct pblk_line *line);
+void pblk_line_close_ws(struct work_struct *work);
+void pblk_line_close(struct pblk *pblk, struct pblk_line *line);
+void pblk_line_mark_bb(struct work_struct *work);
+void pblk_line_run_ws(struct pblk *pblk, struct pblk_line *line, void *priv,
+		      void (*work)(struct work_struct *));
+u64 pblk_line_smeta_start(struct pblk *pblk, struct pblk_line *line);
+int pblk_line_read_smeta(struct pblk *pblk, struct pblk_line *line);
+int pblk_line_read_emeta(struct pblk *pblk, struct pblk_line *line);
+int pblk_blk_erase_async(struct pblk *pblk, struct ppa_addr erase_ppa);
+void pblk_line_put(struct kref *ref);
+struct list_head *pblk_line_gc_list(struct pblk *pblk, struct pblk_line *line);
+u64 pblk_alloc_page(struct pblk *pblk, struct pblk_line *line, int nr_secs);
+int pblk_calc_secs(struct pblk *pblk, unsigned long secs_avail,
+		   unsigned long secs_to_flush);
+void pblk_down_rq(struct pblk *pblk, struct ppa_addr *ppa_list, int nr_ppas,
+		  unsigned long *lun_bitmap);
+void pblk_up_rq(struct pblk *pblk, struct ppa_addr *ppa_list, int nr_ppas,
+		unsigned long *lun_bitmap);
+void pblk_end_bio_sync(struct bio *bio);
+void pblk_end_io_sync(struct nvm_rq *rqd);
+int pblk_bio_add_pages(struct pblk *pblk, struct bio *bio, gfp_t flags,
+		       int nr_pages);
+void pblk_map_pad_invalidate(struct pblk *pblk, struct pblk_line *line,
+			     u64 paddr);
+void pblk_bio_free_pages(struct pblk *pblk, struct bio *bio, int off,
+			 int nr_pages);
+void pblk_map_invalidate(struct pblk *pblk, struct ppa_addr ppa);
+void pblk_update_map(struct pblk *pblk, sector_t lba, struct ppa_addr ppa);
+void pblk_update_map_cache(struct pblk *pblk, sector_t lba,
+			   struct ppa_addr ppa);
+void pblk_update_map_dev(struct pblk *pblk, sector_t lba,
+			 struct ppa_addr ppa, struct ppa_addr entry_line);
+int pblk_update_map_gc(struct pblk *pblk, sector_t lba, struct ppa_addr ppa,
+		       struct pblk_line *gc_line);
+void pblk_lookup_l2p_rand(struct pblk *pblk, struct ppa_addr *ppas,
+			  u64 *lba_list, int nr_secs);
+void pblk_lookup_l2p_seq(struct pblk *pblk, struct ppa_addr *ppas,
+			 sector_t blba, int nr_secs);
+
+/*
+ * pblk user I/O write path
+ */
+int pblk_write_to_cache(struct pblk *pblk, struct bio *bio,
+			unsigned long flags);
+int pblk_write_gc_to_cache(struct pblk *pblk, void *data, u64 *lba_list,
+			   unsigned int nr_entries, unsigned int nr_rec_entries,
+			   struct pblk_line *gc_line, unsigned long flags);
+
+/*
+ * pblk map
+ */
+void pblk_map_erase_rq(struct pblk *pblk, struct nvm_rq *rqd,
+		       unsigned int sentry, unsigned long *lun_bitmap,
+		       unsigned int valid_secs, struct ppa_addr *erase_ppa);
+void pblk_map_rq(struct pblk *pblk, struct nvm_rq *rqd, unsigned int sentry,
+		 unsigned long *lun_bitmap, unsigned int valid_secs,
+		 unsigned int off);
+
+/*
+ * pblk write thread
+ */
+int pblk_write_ts(void *data);
+void pblk_write_timer_fn(unsigned long data);
+void pblk_write_should_kick(struct pblk *pblk);
+
+/*
+ * pblk read path
+ */
+int pblk_submit_read(struct pblk *pblk, struct bio *bio);
+int pblk_submit_read_gc(struct pblk *pblk, u64 *lba_list, void *data,
+			unsigned int nr_secs, unsigned int *secs_to_gc,
+			struct pblk_line *line);
+/*
+ * pblk recovery
+ */
+void pblk_submit_rec(struct work_struct *work);
+struct pblk_line *pblk_recov_l2p(struct pblk *pblk);
+void pblk_recov_pad(struct pblk *pblk);
+__le64 *pblk_recov_get_lba_list(struct pblk *pblk, struct line_emeta *emeta);
+int pblk_recov_setup_rq(struct pblk *pblk, struct pblk_c_ctx *c_ctx,
+			struct pblk_rec_ctx *recovery, u64 *comp_bits,
+			unsigned int comp);
+
+/*
+ * pblk gc
+ */
+#define PBLK_GC_TRIES 3
+
+int pblk_gc_init(struct pblk *pblk);
+void pblk_gc_exit(struct pblk *pblk);
+void pblk_gc_should_start(struct pblk *pblk);
+void pblk_gc_should_stop(struct pblk *pblk);
+int pblk_gc_status(struct pblk *pblk);
+void pblk_gc_sysfs_state_show(struct pblk *pblk, int *gc_enabled,
+			      int *gc_active);
+void pblk_gc_sysfs_force(struct pblk *pblk, int force);
+
+/*
+ * pblk rate limiter
+ */
+void pblk_rl_init(struct pblk_rl *rl, int budget);
+void pblk_rl_free(struct pblk_rl *rl);
+int pblk_rl_gc_thrs(struct pblk_rl *rl);
+unsigned long pblk_rl_nr_free_blks(struct pblk_rl *rl);
+int pblk_rl_user_may_insert(struct pblk_rl *rl, int nr_entries);
+void pblk_rl_user_in(struct pblk_rl *rl, int nr_entries);
+int pblk_rl_gc_may_insert(struct pblk_rl *rl, int nr_entries);
+void pblk_rl_gc_in(struct pblk_rl *rl, int nr_entries);
+void pblk_rl_out(struct pblk_rl *rl, int nr_user, int nr_gc);
+void pblk_rl_set_gc_rsc(struct pblk_rl *rl, int rsv);
+int pblk_rl_sysfs_rate_show(struct pblk_rl *rl);
+void pblk_rl_free_lines_inc(struct pblk_rl *rl, struct pblk_line *line);
+void pblk_rl_free_lines_dec(struct pblk_rl *rl, struct pblk_line *line);
+
+/*
+ * pblk sysfs
+ */
+int pblk_sysfs_init(struct gendisk *tdisk);
+void pblk_sysfs_exit(struct gendisk *tdisk);
+
+static inline void *pblk_malloc(size_t size, int type, gfp_t flags)
+{
+	if (type == PBLK_KMALLOC_META)
+		return kmalloc(size, flags);
+	return vmalloc(size);
+}
+
+static inline void pblk_mfree(void *ptr, int type)
+{
+	if (type == PBLK_KMALLOC_META)
+		kfree(ptr);
+	else
+		vfree(ptr);
+}
+
+static inline struct nvm_rq *nvm_rq_from_c_ctx(void *c_ctx)
+{
+	return c_ctx - sizeof(struct nvm_rq);
+}
+
+static inline void *pblk_line_emeta_to_lbas(struct line_emeta *emeta)
+{
+	return (emeta) + 1;
+}
+
+#define NVM_MEM_PAGE_WRITE (8)
+
+static inline int pblk_pad_distance(struct pblk *pblk)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+
+	return NVM_MEM_PAGE_WRITE * geo->nr_luns * geo->sec_per_pl;
+}
+
+static inline int pblk_dev_ppa_to_line(struct ppa_addr p)
+{
+	return p.g.blk;
+}
+
+static inline int pblk_tgt_ppa_to_line(struct ppa_addr p)
+{
+	return p.g.blk;
+}
+
+static inline int pblk_ppa_to_pos(struct nvm_geo *geo, struct ppa_addr p)
+{
+	return p.g.lun * geo->nr_chnls + p.g.ch;
+}
+
+/* A block within a line corresponds to the lun */
+static inline int pblk_dev_ppa_to_pos(struct nvm_geo *geo, struct ppa_addr p)
+{
+	return p.g.lun * geo->nr_chnls + p.g.ch;
+}
+
+static inline struct ppa_addr pblk_ppa32_to_ppa64(struct pblk *pblk, u32 ppa32)
+{
+	struct ppa_addr ppa64;
+
+	ppa64.ppa = 0;
+
+	if (ppa32 == -1) {
+		ppa64.ppa = ADDR_EMPTY;
+	} else if (ppa32 & (1U << 31)) {
+		ppa64.c.line = ppa32 & ((~0U) >> 1);
+		ppa64.c.is_cached = 1;
+	} else {
+		ppa64.g.blk = (ppa32 & pblk->ppaf.blk_mask) >>
+							pblk->ppaf.blk_offset;
+		ppa64.g.pg = (ppa32 & pblk->ppaf.pg_mask) >>
+							pblk->ppaf.pg_offset;
+		ppa64.g.lun = (ppa32 & pblk->ppaf.lun_mask) >>
+							pblk->ppaf.lun_offset;
+		ppa64.g.ch = (ppa32 & pblk->ppaf.ch_mask) >>
+							pblk->ppaf.ch_offset;
+		ppa64.g.pl = (ppa32 & pblk->ppaf.pln_mask) >>
+							pblk->ppaf.pln_offset;
+		ppa64.g.sec = (ppa32 & pblk->ppaf.sec_mask) >>
+							pblk->ppaf.sec_offset;
+	}
+
+	return ppa64;
+}
+
+static inline struct ppa_addr pblk_trans_map_get(struct pblk *pblk,
+								sector_t lba)
+{
+	struct ppa_addr ppa;
+
+	if (pblk->ppaf_bitsize < 32) {
+		u32 *map = (u32 *)pblk->trans_map;
+
+		ppa = pblk_ppa32_to_ppa64(pblk, map[lba]);
+	} else {
+		struct ppa_addr *map = (struct ppa_addr *)pblk->trans_map;
+
+		ppa = map[lba];
+	}
+
+	return ppa;
+}
+
+static inline u32 pblk_ppa64_to_ppa32(struct pblk *pblk, struct ppa_addr ppa64)
+{
+	u32 ppa32 = 0;
+
+	if (ppa64.ppa == ADDR_EMPTY) {
+		ppa32 = ~0U;
+	} else if (ppa64.c.is_cached) {
+		ppa32 |= ppa64.c.line;
+		ppa32 |= 1U << 31;
+	} else {
+		ppa32 |= ppa64.g.blk << pblk->ppaf.blk_offset;
+		ppa32 |= ppa64.g.pg << pblk->ppaf.pg_offset;
+		ppa32 |= ppa64.g.lun << pblk->ppaf.lun_offset;
+		ppa32 |= ppa64.g.ch << pblk->ppaf.ch_offset;
+		ppa32 |= ppa64.g.pl << pblk->ppaf.pln_offset;
+		ppa32 |= ppa64.g.sec << pblk->ppaf.sec_offset;
+	}
+
+	return ppa32;
+}
+
+static inline void pblk_trans_map_set(struct pblk *pblk, sector_t lba,
+						struct ppa_addr ppa)
+{
+	if (pblk->ppaf_bitsize < 32) {
+		u32 *map = (u32 *)pblk->trans_map;
+
+		map[lba] = pblk_ppa64_to_ppa32(pblk, ppa);
+	} else {
+		u64 *map = (u64 *)pblk->trans_map;
+
+		map[lba] = ppa.ppa;
+	}
+}
+
+static inline u64 pblk_dev_ppa_to_line_addr(struct pblk *pblk,
+							struct ppa_addr p)
+{
+	u64 paddr;
+
+	paddr = 0;
+	paddr |= (u64)p.g.pg << pblk->ppaf.pg_offset;
+	paddr |= (u64)p.g.lun << pblk->ppaf.lun_offset;
+	paddr |= (u64)p.g.ch << pblk->ppaf.ch_offset;
+	paddr |= (u64)p.g.pl << pblk->ppaf.pln_offset;
+	paddr |= (u64)p.g.sec << pblk->ppaf.sec_offset;
+
+	return paddr;
+}
+
+static inline int pblk_ppa_empty(struct ppa_addr ppa_addr)
+{
+	return (ppa_addr.ppa == ADDR_EMPTY);
+}
+
+static inline void pblk_ppa_set_empty(struct ppa_addr *ppa_addr)
+{
+	ppa_addr->ppa = ADDR_EMPTY;
+}
+
+static inline int pblk_addr_in_cache(struct ppa_addr ppa)
+{
+	return (ppa.ppa != ADDR_EMPTY && ppa.c.is_cached);
+}
+
+static inline int pblk_addr_to_cacheline(struct ppa_addr ppa)
+{
+	return ppa.c.line;
+}
+
+static inline struct ppa_addr pblk_cacheline_to_addr(int addr)
+{
+	struct ppa_addr p;
+
+	p.c.line = addr;
+	p.c.is_cached = 1;
+
+	return p;
+}
+
+static inline struct ppa_addr addr_to_gen_ppa(struct pblk *pblk, u64 paddr,
+					      u64 line_id)
+{
+	struct ppa_addr ppa;
+
+	ppa.ppa = 0;
+	ppa.g.blk = line_id;
+	ppa.g.pg = (paddr & pblk->ppaf.pg_mask) >> pblk->ppaf.pg_offset;
+	ppa.g.lun = (paddr & pblk->ppaf.lun_mask) >> pblk->ppaf.lun_offset;
+	ppa.g.ch = (paddr & pblk->ppaf.ch_mask) >> pblk->ppaf.ch_offset;
+	ppa.g.pl = (paddr & pblk->ppaf.pln_mask) >> pblk->ppaf.pln_offset;
+	ppa.g.sec = (paddr & pblk->ppaf.sec_mask) >> pblk->ppaf.sec_offset;
+
+	return ppa;
+}
+
+static inline struct ppa_addr addr_to_pblk_ppa(struct pblk *pblk, u64 paddr,
+					 u64 line_id)
+{
+	struct ppa_addr ppa;
+
+	ppa = addr_to_gen_ppa(pblk, paddr, line_id);
+
+	return ppa;
+}
+
+static inline u32 pblk_calc_meta_header_crc(struct pblk *pblk,
+					    struct line_smeta *smeta)
+{
+	u32 crc = ~(u32)0;
+
+	crc = crc32_le(crc, (unsigned char *)smeta + sizeof(crc),
+				sizeof(struct line_header) - sizeof(crc));
+
+	return crc;
+}
+
+static inline u32 pblk_calc_smeta_crc(struct pblk *pblk,
+				      struct line_smeta *smeta)
+{
+	struct pblk_line_meta *lm = &pblk->lm;
+	u32 crc = ~(u32)0;
+
+	crc = crc32_le(crc, (unsigned char *)smeta +
+				sizeof(struct line_header) + sizeof(crc),
+				lm->smeta_len -
+				sizeof(struct line_header) - sizeof(crc));
+
+	return crc;
+}
+
+static inline u32 pblk_calc_emeta_crc(struct pblk *pblk,
+				      struct line_emeta *emeta)
+{
+	struct pblk_line_meta *lm = &pblk->lm;
+	u32 crc = ~(u32)0;
+
+	crc = crc32_le(crc, (unsigned char *)emeta +
+				sizeof(struct line_header) + sizeof(crc),
+				lm->emeta_len -
+				sizeof(struct line_header) - sizeof(crc));
+
+	return crc;
+}
+
+static inline int pblk_set_progr_mode(struct pblk *pblk, int type)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct nvm_geo *geo = &dev->geo;
+	int flags;
+
+	flags = geo->plane_mode >> 1;
+
+	if (type == WRITE)
+		flags |= NVM_IO_SCRAMBLE_ENABLE;
+
+	return flags;
+}
+
+static inline int pblk_set_read_mode(struct pblk *pblk)
+{
+	return NVM_IO_SNGL_ACCESS | NVM_IO_SUSPEND | NVM_IO_SCRAMBLE_ENABLE;
+}
+
+#ifdef CONFIG_NVM_DEBUG
+static inline void print_ppa(struct ppa_addr *p, char *msg, int error)
+{
+	if (p->c.is_cached) {
+		pr_err("ppa: (%s: %x) cache line: %llu\n",
+				msg, error, (u64)p->c.line);
+	} else {
+		pr_err("ppa: (%s: %x):ch:%d,lun:%d,blk:%d,pg:%d,pl:%d,sec:%d\n",
+			msg, error,
+			p->g.ch, p->g.lun, p->g.blk,
+			p->g.pg, p->g.pl, p->g.sec);
+	}
+}
+
+static inline void pblk_print_failed_rqd(struct pblk *pblk, struct nvm_rq *rqd,
+					 int error)
+{
+	int bit = -1;
+
+	if (rqd->nr_ppas ==  1) {
+		print_ppa(&rqd->ppa_addr, "rqd", error);
+		return;
+	}
+
+	while ((bit = find_next_bit((void *)&rqd->ppa_status, rqd->nr_ppas,
+						bit + 1)) < rqd->nr_ppas) {
+		print_ppa(&rqd->ppa_list[bit], "rqd", error);
+	}
+
+	pr_err("error:%d, ppa_status:%llx\n", error, rqd->ppa_status);
+}
+#endif
+
+static inline int pblk_boundary_ppa_checks(struct nvm_tgt_dev *tgt_dev,
+				       struct ppa_addr *ppas, int nr_ppas)
+{
+	struct nvm_geo *geo = &tgt_dev->geo;
+	struct ppa_addr *ppa;
+	int i;
+
+	for (i = 0; i < nr_ppas; i++) {
+		ppa = &ppas[i];
+
+		if (!ppa->c.is_cached &&
+				ppa->g.ch < geo->nr_chnls &&
+				ppa->g.lun < geo->luns_per_chnl &&
+				ppa->g.pl < geo->nr_planes &&
+				ppa->g.blk < geo->blks_per_lun &&
+				ppa->g.pg < geo->pgs_per_blk &&
+				ppa->g.sec < geo->sec_per_pg)
+			continue;
+
+#ifdef CONFIG_NVM_DEBUG
+		print_ppa(ppa, "boundary", i);
+#endif
+		return 1;
+	}
+	return 0;
+}
+
+static inline int pblk_boundary_paddr_checks(struct pblk *pblk, u64 paddr)
+{
+	struct pblk_line_meta *lm = &pblk->lm;
+
+	if (paddr > lm->sec_per_line)
+		return 1;
+
+	return 0;
+}
+
+static inline unsigned int pblk_get_bi_idx(struct bio *bio)
+{
+	return bio->bi_iter.bi_idx;
+}
+
+static inline sector_t pblk_get_lba(struct bio *bio)
+{
+	return bio->bi_iter.bi_sector / NR_PHY_IN_LOG;
+}
+
+static inline unsigned int pblk_get_secs(struct bio *bio)
+{
+	return  bio->bi_iter.bi_size / PBLK_EXPOSED_PAGE_SIZE;
+}
+
+static inline sector_t pblk_get_sector(sector_t lba)
+{
+	return lba * NR_PHY_IN_LOG;
+}
+
+static inline void pblk_setup_uuid(struct pblk *pblk)
+{
+	uuid_le uuid;
+
+	uuid_le_gen(&uuid);
+	memcpy(pblk->instance_uuid, uuid.b, 16);
+}
+#endif /* PBLK_H_ */