lightnvm: dynamic DMA pool entry size

Currently lightnvm and pblk uses single DMA pool, for which the entry
size always is equal to PAGE_SIZE. The contents of each entry allocated
from the DMA pool consists of a PPA list (8bytes * 64), leaving
56bytes * 64 space for metadata. Since the metadata field can be bigger,
such as 128 bytes, the static size does not cover this use-case.

This patch adds support for I/O metadata above 56 bytes by changing DMA
pool size based on device meta size and allows pblk to use OOB metadata
>=16B.
Reviewed-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Igor Konopko <igor.j.konopko@intel.com>
Signed-off-by: Matias Bjørling <mb@lightnvm.io>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/lightnvm/core.c

@@ -1140,7 +1140,7 @@ EXPORT_SYMBOL(nvm_alloc_dev);
 
 int nvm_register(struct nvm_dev *dev)
 {
-	int ret;
+	int ret, exp_pool_size;
 
 	if (!dev->q || !dev->ops)
 		return -EINVAL;
@@ -1149,7 +1149,12 @@ int nvm_register(struct nvm_dev *dev)
 	if (ret)
 		return ret;
 
-	dev->dma_pool = dev->ops->create_dma_pool(dev, "ppalist");
+	exp_pool_size = max_t(int, PAGE_SIZE,
+			      (NVM_MAX_VLBA * (sizeof(u64) + dev->geo.sos)));
+	exp_pool_size = round_up(exp_pool_size, PAGE_SIZE);
+
+	dev->dma_pool = dev->ops->create_dma_pool(dev, "ppalist",
+						  exp_pool_size);
 	if (!dev->dma_pool) {
 		pr_err("nvm: could not create dma pool\n");
 		nvm_free(dev);

drivers/lightnvm/pblk-core.c

@@ -250,8 +250,8 @@ int pblk_alloc_rqd_meta(struct pblk *pblk, struct nvm_rq *rqd)
 	if (rqd->nr_ppas == 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;
+	rqd->ppa_list = rqd->meta_list + pblk_dma_meta_size(pblk);
+	rqd->dma_ppa_list = rqd->dma_meta_list + pblk_dma_meta_size(pblk);
 
 	return 0;
 }
@@ -846,8 +846,8 @@ int pblk_line_emeta_read(struct pblk *pblk, struct pblk_line *line,
 	if (!meta_list)
 		return -ENOMEM;
 
-	ppa_list = meta_list + pblk_dma_meta_size;
-	dma_ppa_list = dma_meta_list + pblk_dma_meta_size;
+	ppa_list = meta_list + pblk_dma_meta_size(pblk);
+	dma_ppa_list = dma_meta_list + pblk_dma_meta_size(pblk);
 
 next_rq:
 	memset(&rqd, 0, sizeof(struct nvm_rq));

drivers/lightnvm/pblk-init.c

@@ -406,7 +406,7 @@ static int pblk_core_init(struct pblk *pblk)
 	pblk_set_sec_per_write(pblk, pblk->min_write_pgs);
 
 	pblk->oob_meta_size = geo->sos;
-	if (pblk->oob_meta_size != sizeof(struct pblk_sec_meta)) {
+	if (pblk->oob_meta_size < sizeof(struct pblk_sec_meta)) {
 		pblk_err(pblk, "Unsupported metadata size\n");
 		return -EINVAL;
 	}

drivers/lightnvm/pblk-recovery.c

@@ -481,8 +481,8 @@ static int pblk_recov_l2p_from_oob(struct pblk *pblk, struct pblk_line *line)
 	if (!meta_list)
 		return -ENOMEM;
 
-	ppa_list = (void *)(meta_list) + pblk_dma_meta_size;
-	dma_ppa_list = dma_meta_list + pblk_dma_meta_size;
+	ppa_list = (void *)(meta_list) + pblk_dma_meta_size(pblk);
+	dma_ppa_list = dma_meta_list + pblk_dma_meta_size(pblk);
 
 	data = kcalloc(pblk->max_write_pgs, geo->csecs, GFP_KERNEL);
 	if (!data) {

drivers/lightnvm/pblk.h

@@ -104,7 +104,6 @@ enum {
 	PBLK_RL_LOW = 4
 };
 
-#define pblk_dma_meta_size (sizeof(struct pblk_sec_meta) * NVM_MAX_VLBA)
 #define pblk_dma_ppa_size (sizeof(u64) * NVM_MAX_VLBA)
 
 /* write buffer completion context */
@@ -1388,4 +1387,9 @@ static inline struct pblk_sec_meta *pblk_get_meta(struct pblk *pblk,
 {
 	return meta + pblk->oob_meta_size * index;
 }
+
+static inline int pblk_dma_meta_size(struct pblk *pblk)
+{
+	return pblk->oob_meta_size * NVM_MAX_VLBA;
+}
 #endif /* PBLK_H_ */

drivers/nvme/host/lightnvm.c

@@ -732,11 +732,12 @@ static int nvme_nvm_submit_io_sync(struct nvm_dev *dev, struct nvm_rq *rqd)
 	return ret;
 }
 
-static void *nvme_nvm_create_dma_pool(struct nvm_dev *nvmdev, char *name)
+static void *nvme_nvm_create_dma_pool(struct nvm_dev *nvmdev, char *name,
+					int size)
 {
 	struct nvme_ns *ns = nvmdev->q->queuedata;
 
-	return dma_pool_create(name, ns->ctrl->dev, PAGE_SIZE, PAGE_SIZE, 0);
+	return dma_pool_create(name, ns->ctrl->dev, size, PAGE_SIZE, 0);
 }
 
 static void nvme_nvm_destroy_dma_pool(void *pool)

include/linux/lightnvm.h

@@ -90,7 +90,7 @@ typedef int (nvm_get_chk_meta_fn)(struct nvm_dev *, sector_t, int,
 							struct nvm_chk_meta *);
 typedef int (nvm_submit_io_fn)(struct nvm_dev *, struct nvm_rq *);
 typedef int (nvm_submit_io_sync_fn)(struct nvm_dev *, struct nvm_rq *);
-typedef void *(nvm_create_dma_pool_fn)(struct nvm_dev *, char *);
+typedef void *(nvm_create_dma_pool_fn)(struct nvm_dev *, char *, int);
 typedef void (nvm_destroy_dma_pool_fn)(void *);
 typedef void *(nvm_dev_dma_alloc_fn)(struct nvm_dev *, void *, gfp_t,
 								dma_addr_t *);