lightnvm: eliminate nvm_lun abstraction in mm

In order to naturally support multi-target instances on an Open-Channel
SSD, targets should own the LUNs they get blocks from and manage
provisioning internally. This is done in several steps.

Since targets own the LUNs the are instantiated on top of and manage the
free block list internally, there is no need for a LUN abstraction in
the media manager. LUNs are intrinsically managed as in the physical
layout (ch:0,lun:0, ..., ch:0,lun:n, ch:1,lun:0, ch:1,lun:n, ...,
ch:m,lun:0, ch:m,lun:n) and given to the targets based on the target
creation ioctl. This simplifies LUN management and clears the path for a
partition manager to sit directly underneath LightNVM targets.
Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>

drivers/lightnvm/core.c

@@ -203,15 +203,19 @@ int nvm_set_bb_tbl(struct nvm_dev *dev, struct ppa_addr *ppas, int nr_ppas,
 }
 EXPORT_SYMBOL(nvm_set_bb_tbl);
 
-int nvm_submit_io(struct nvm_dev *dev, struct nvm_rq *rqd)
+int nvm_submit_io(struct nvm_tgt_dev *tgt_dev, struct nvm_rq *rqd)
 {
-	return dev->mt->submit_io(dev, rqd);
+	struct nvm_dev *dev = tgt_dev->parent;
+
+	return dev->mt->submit_io(tgt_dev, rqd);
 }
 EXPORT_SYMBOL(nvm_submit_io);
 
-int nvm_erase_blk(struct nvm_dev *dev, struct ppa_addr *p, int flags)
+int nvm_erase_blk(struct nvm_tgt_dev *tgt_dev, struct ppa_addr *p, int flags)
 {
-	return dev->mt->erase_blk(dev, p, flags);
+	struct nvm_dev *dev = tgt_dev->parent;
+
+	return dev->mt->erase_blk(tgt_dev, p, flags);
 }
 EXPORT_SYMBOL(nvm_erase_blk);
 
@@ -350,7 +354,7 @@ static int __nvm_submit_ppa(struct nvm_dev *dev, struct nvm_rq *rqd, int opcode,
 
 	nvm_generic_to_addr_mode(dev, rqd);
 
-	rqd->dev = dev;
+	rqd->dev = NULL;
 	rqd->opcode = opcode;
 	rqd->flags = flags;
 	rqd->bio = bio;

drivers/lightnvm/gennvm.h

@@ -24,19 +24,37 @@ struct gen_dev {
 	struct nvm_dev *dev;
 
 	int nr_luns;
-	struct nvm_lun *luns;
 	struct list_head area_list;
 
 	struct mutex lock;
 	struct list_head targets;
 };
 
+/* Map between virtual and physical channel and lun */
+struct gen_ch_map {
+	int ch_off;
+	int nr_luns;
+	int *lun_offs;
+};
+
+struct gen_dev_map {
+	struct gen_ch_map *chnls;
+	int nr_chnls;
+};
+
 struct gen_area {
 	struct list_head list;
 	sector_t begin;
 	sector_t end;	/* end is excluded */
 };
 
+static inline void *ch_map_to_lun_offs(struct gen_ch_map *ch_map)
+{
+	return ch_map + 1;
+}
+
+typedef int (gen_trans_fn)(struct nvm_tgt_dev *, struct ppa_addr *);
+
 #define gen_for_each_lun(bm, lun, i) \
 		for ((i) = 0, lun = &(bm)->luns[0]; \
 			(i) < (bm)->nr_luns; (i)++, lun = &(bm)->luns[(i)])

drivers/lightnvm/rrpc.h

@@ -74,7 +74,9 @@ struct rrpc_block {
 
 struct rrpc_lun {
 	struct rrpc *rrpc;
-	struct nvm_lun *parent;
+
+	int id;
+	struct ppa_addr bppa;
 
 	struct rrpc_block *cur, *gc_cur;
 	struct rrpc_block *blocks;	/* Reference to block allocation */
@@ -107,7 +109,6 @@ struct rrpc {
 	struct gendisk *disk;
 
 	sector_t soffset; /* logical sector offset */
-	u64 poffset; /* physical page offset */
 
 	int nr_luns;
 	struct rrpc_lun *luns;
@@ -164,14 +165,37 @@ struct rrpc_rev_addr {
 	u64 addr;
 };
 
+static inline struct ppa_addr rrpc_linear_to_generic_addr(struct nvm_geo *geo,
+							  struct ppa_addr r)
+{
+	struct ppa_addr l;
+	int secs, pgs;
+	sector_t ppa = r.ppa;
+
+	l.ppa = 0;
+
+	div_u64_rem(ppa, geo->sec_per_pg, &secs);
+	l.g.sec = secs;
+
+	sector_div(ppa, geo->sec_per_pg);
+	div_u64_rem(ppa, geo->pgs_per_blk, &pgs);
+	l.g.pg = pgs;
+
+	return l;
+}
+
+static inline struct ppa_addr rrpc_recov_addr(struct nvm_dev *dev, u64 pba)
+{
+	return linear_to_generic_addr(&dev->geo, pba);
+}
+
 static inline u64 rrpc_blk_to_ppa(struct rrpc *rrpc, struct rrpc_block *rblk)
 {
 	struct nvm_tgt_dev *dev = rrpc->dev;
 	struct nvm_geo *geo = &dev->geo;
 	struct rrpc_lun *rlun = rblk->rlun;
-	struct nvm_lun *lun = rlun->parent;
 
-	return (lun->id * geo->sec_per_lun) + (rblk->id * geo->sec_per_blk);
+	return (rlun->id * geo->sec_per_lun) + (rblk->id * geo->sec_per_blk);
 }
 
 static inline sector_t rrpc_get_laddr(struct bio *bio)

drivers/nvme/host/lightnvm.c

@@ -371,6 +371,9 @@ static int nvme_nvm_get_l2p_tbl(struct nvm_dev *nvmdev, u64 slba, u32 nlb,
 			return -EINVAL;
 		}
 
+		/* Transform physical address to target address space */
+		nvmdev->mt->part_to_tgt(nvmdev, entries, cmd_nlb);
+
 		if (update_l2p(cmd_slba, cmd_nlb, entries, priv)) {
 			ret = -EINTR;
 			goto out;

include/linux/lightnvm.h

@@ -47,6 +47,7 @@ struct ppa_addr {
 struct nvm_rq;
 struct nvm_id;
 struct nvm_dev;
+struct nvm_tgt_dev;
 
 typedef int (nvm_l2p_update_fn)(u64, u32, __le64 *, void *);
 typedef int (nvm_id_fn)(struct nvm_dev *, struct nvm_id *);
@@ -210,7 +211,6 @@ struct nvm_id {
 
 struct nvm_target {
 	struct list_head list;
-	struct list_head lun_list;
 	struct nvm_tgt_dev *dev;
 	struct nvm_tgt_type *type;
 	struct gendisk *disk;
@@ -231,7 +231,7 @@ typedef void (nvm_end_io_fn)(struct nvm_rq *);
 
 struct nvm_rq {
 	struct nvm_tgt_instance *ins;
-	struct nvm_dev *dev;
+	struct nvm_tgt_dev *dev;
 
 	struct bio *bio;
 
@@ -266,15 +266,6 @@ static inline void *nvm_rq_to_pdu(struct nvm_rq *rqdata)
 	return rqdata + 1;
 }
 
-struct nvm_lun {
-	int id;
-
-	int lun_id;
-	int chnl_id;
-
-	struct list_head list;
-};
-
 enum {
 	NVM_BLK_ST_FREE =	0x1,	/* Free block */
 	NVM_BLK_ST_TGT =	0x2,	/* Block in use by target */
@@ -321,6 +312,9 @@ struct nvm_tgt_dev {
 	/* Device information */
 	struct nvm_geo geo;
 
+	/* Base ppas for target LUNs */
+	struct ppa_addr *luns;
+
 	sector_t total_secs;
 
 	struct nvm_id identity;
@@ -330,6 +324,7 @@ struct nvm_tgt_dev {
 	struct nvm_dev_ops *ops;
 
 	void *parent;
+	void *map;
 };
 
 struct nvm_dev {
@@ -363,16 +358,18 @@ struct nvm_dev {
 	char name[DISK_NAME_LEN];
 	void *private_data;
 
+	void *rmap;
+
 	struct mutex mlock;
 	spinlock_t lock;
 };
 
 static inline struct ppa_addr linear_to_generic_addr(struct nvm_geo *geo,
-							struct ppa_addr r)
+						     u64 pba)
 {
 	struct ppa_addr l;
 	int secs, pgs, blks, luns;
-	sector_t ppa = r.ppa;
+	sector_t ppa = pba;
 
 	l.ppa = 0;
 
@@ -465,8 +462,7 @@ static inline int ppa_to_slc(struct nvm_dev *dev, int slc_pg)
 
 typedef blk_qc_t (nvm_tgt_make_rq_fn)(struct request_queue *, struct bio *);
 typedef sector_t (nvm_tgt_capacity_fn)(void *);
-typedef void *(nvm_tgt_init_fn)(struct nvm_tgt_dev *, struct gendisk *,
-				struct list_head *lun_list);
+typedef void *(nvm_tgt_init_fn)(struct nvm_tgt_dev *, struct gendisk *);
 typedef void (nvm_tgt_exit_fn)(void *);
 
 struct nvm_tgt_type {
@@ -499,10 +495,11 @@ typedef void (nvmm_unregister_fn)(struct nvm_dev *);
 
 typedef int (nvmm_create_tgt_fn)(struct nvm_dev *, struct nvm_ioctl_create *);
 typedef int (nvmm_remove_tgt_fn)(struct nvm_dev *, struct nvm_ioctl_remove *);
-typedef int (nvmm_submit_io_fn)(struct nvm_dev *, struct nvm_rq *);
-typedef int (nvmm_erase_blk_fn)(struct nvm_dev *, struct ppa_addr *, int);
+typedef int (nvmm_submit_io_fn)(struct nvm_tgt_dev *, struct nvm_rq *);
+typedef int (nvmm_erase_blk_fn)(struct nvm_tgt_dev *, struct ppa_addr *, int);
 typedef int (nvmm_get_area_fn)(struct nvm_dev *, sector_t *, sector_t);
 typedef void (nvmm_put_area_fn)(struct nvm_dev *, sector_t);
+typedef void (nvmm_part_to_tgt_fn)(struct nvm_dev *, sector_t*, int);
 
 struct nvmm_type {
 	const char *name;
@@ -520,6 +517,8 @@ struct nvmm_type {
 	nvmm_get_area_fn *get_area;
 	nvmm_put_area_fn *put_area;
 
+	nvmm_part_to_tgt_fn *part_to_tgt;
+
 	struct list_head list;
 };
 
@@ -533,14 +532,18 @@ extern void nvm_unregister(struct nvm_dev *);
 extern int nvm_set_bb_tbl(struct nvm_dev *dev, struct ppa_addr *ppas,
 							int nr_ppas, int type);
 
-extern int nvm_submit_io(struct nvm_dev *, struct nvm_rq *);
+extern int nvm_submit_io(struct nvm_tgt_dev *, struct nvm_rq *);
 extern void nvm_generic_to_addr_mode(struct nvm_dev *, struct nvm_rq *);
 extern void nvm_addr_to_generic_mode(struct nvm_dev *, struct nvm_rq *);
 extern int nvm_set_rqd_ppalist(struct nvm_dev *, struct nvm_rq *,
 					const struct ppa_addr *, int, int);
 extern void nvm_free_rqd_ppalist(struct nvm_dev *, struct nvm_rq *);
 extern int nvm_erase_ppa(struct nvm_dev *, struct ppa_addr *, int, int);
-extern int nvm_erase_blk(struct nvm_dev *, struct ppa_addr *, int);
+extern int nvm_erase_blk(struct nvm_tgt_dev *, struct ppa_addr *, int);
+extern int nvm_get_l2p_tbl(struct nvm_dev *, u64, u32, nvm_l2p_update_fn *,
+			   void *);
+extern int nvm_get_area(struct nvm_dev *, sector_t *, sector_t);
+extern void nvm_put_area(struct nvm_dev *, sector_t);
 extern void nvm_end_io(struct nvm_rq *, int);
 extern int nvm_submit_ppa(struct nvm_dev *, struct ppa_addr *, int, int, int,
 								void *, int);