[PATCH V2] lightnvm: generalize rrpc ppa calculations

[Javier GonzÃlez]

From: Javier GonzÃlez <jg@xxxxxxxxxxx>

In rrpc, some calculations assume a certain configuration (e.g., 1 LUN,
1 sector per page). The reason behind this was that we have used a simple
configuration in QEMU to test core features generally in LightNVM, and
concretely in rrpc. This patch relaxes these assumptions and generalizes
calculations in order to support real hardware. Note that more complex
configurations in QEMU, that allow to simulate this hardware, are also
pushed into the qemu-nvme repository implementing LightNVM support,
available under the Open-Channel SSD project in github [1].

[1] https://github.com/OpenChannelSSD/qemu-nvme

V2: Use right operations to calculate modulus on 64-bit integers.

Signed-off-by: Javier GonzÃlez <javier@xxxxxxxxxxxx>
---
 drivers/lightnvm/rrpc.c | 48 +++++++++++++++++++++++++++++++-----------------
 drivers/lightnvm/rrpc.h |  9 +++++++++
 2 files changed, 40 insertions(+), 17 deletions(-)

diff --git a/drivers/lightnvm/rrpc.c b/drivers/lightnvm/rrpc.c
index 775bf6c2..8234378 100644
--- a/drivers/lightnvm/rrpc.c
+++ b/drivers/lightnvm/rrpc.c
@@ -38,7 +38,7 @@ static void rrpc_page_invalidate(struct rrpc *rrpc, struct rrpc_addr *a)
 
 	spin_lock(&rblk->lock);
 
-	div_u64_rem(a->addr, rrpc->dev->pgs_per_blk, &pg_offset);
+	div_u64_rem(a->addr, rrpc->dev->sec_per_blk, &pg_offset);
 	WARN_ON(test_and_set_bit(pg_offset, rblk->invalid_pages));
 	rblk->nr_invalid_pages++;
 
@@ -113,14 +113,24 @@ static void rrpc_discard(struct rrpc *rrpc, struct bio *bio)
 
 static int block_is_full(struct rrpc *rrpc, struct rrpc_block *rblk)
 {
-	return (rblk->next_page == rrpc->dev->pgs_per_blk);
+	return (rblk->next_page == rrpc->dev->sec_per_blk);
 }
 
+/* Calculate relative addr for the given block, considering instantiated LUNs */
+static u64 block_to_rel_addr(struct rrpc *rrpc, struct rrpc_block *rblk)
+{
+	struct nvm_block *blk = rblk->parent;
+	int lun_blk = blk->id % (rrpc->dev->blks_per_lun * rrpc->nr_luns);
+
+	return lun_blk * rrpc->dev->sec_per_blk;
+}
+
+/* Calculate global addr for the given block */
 static u64 block_to_addr(struct rrpc *rrpc, struct rrpc_block *rblk)
 {
 	struct nvm_block *blk = rblk->parent;
 
-	return blk->id * rrpc->dev->pgs_per_blk;
+	return blk->id * rrpc->dev->sec_per_blk;
 }
 
 static struct ppa_addr linear_to_generic_addr(struct nvm_dev *dev,
@@ -136,7 +146,7 @@ static struct ppa_addr linear_to_generic_addr(struct nvm_dev *dev,
 	l.g.sec = secs;
 
 	sector_div(ppa, dev->sec_per_pg);
-	div_u64_rem(ppa, dev->sec_per_blk, &pgs);
+	div_u64_rem(ppa, dev->pgs_per_blk, &pgs);
 	l.g.pg = pgs;
 
 	sector_div(ppa, dev->pgs_per_blk);
@@ -191,12 +201,12 @@ static struct rrpc_block *rrpc_get_blk(struct rrpc *rrpc, struct rrpc_lun *rlun,
 		return NULL;
 	}
 
-	rblk = &rlun->blocks[blk->id];
+	rblk = rrpc_get_rblk(rlun, blk->id);
 	list_add_tail(&rblk->list, &rlun->open_list);
 	spin_unlock(&lun->lock);
 
 	blk->priv = rblk;
-	bitmap_zero(rblk->invalid_pages, rrpc->dev->pgs_per_blk);
+	bitmap_zero(rblk->invalid_pages, rrpc->dev->sec_per_blk);
 	rblk->next_page = 0;
 	rblk->nr_invalid_pages = 0;
 	atomic_set(&rblk->data_cmnt_size, 0);
@@ -286,11 +296,11 @@ static int rrpc_move_valid_pages(struct rrpc *rrpc, struct rrpc_block *rblk)
 	struct bio *bio;
 	struct page *page;
 	int slot;
-	int nr_pgs_per_blk = rrpc->dev->pgs_per_blk;
+	int nr_sec_per_blk = rrpc->dev->sec_per_blk;
 	u64 phys_addr;
 	DECLARE_COMPLETION_ONSTACK(wait);
 
-	if (bitmap_full(rblk->invalid_pages, nr_pgs_per_blk))
+	if (bitmap_full(rblk->invalid_pages, nr_sec_per_blk))
 		return 0;
 
 	bio = bio_alloc(GFP_NOIO, 1);
@@ -306,10 +316,10 @@ static int rrpc_move_valid_pages(struct rrpc *rrpc, struct rrpc_block *rblk)
 	}
 
 	while ((slot = find_first_zero_bit(rblk->invalid_pages,
-					    nr_pgs_per_blk)) < nr_pgs_per_blk) {
+					    nr_sec_per_blk)) < nr_sec_per_blk) {
 
 		/* Lock laddr */
-		phys_addr = (rblk->parent->id * nr_pgs_per_blk) + slot;
+		phys_addr = rblk->parent->id * nr_sec_per_blk + slot;
 
 try:
 		spin_lock(&rrpc->rev_lock);
@@ -381,7 +391,7 @@ finished:
 	mempool_free(page, rrpc->page_pool);
 	bio_put(bio);
 
-	if (!bitmap_full(rblk->invalid_pages, nr_pgs_per_blk)) {
+	if (!bitmap_full(rblk->invalid_pages, nr_sec_per_blk)) {
 		pr_err("nvm: failed to garbage collect block\n");
 		return -EIO;
 	}
@@ -677,7 +687,7 @@ static void rrpc_end_io_write(struct rrpc *rrpc, struct rrpc_rq *rrqd,
 		lun = rblk->parent->lun;
 
 		cmnt_size = atomic_inc_return(&rblk->data_cmnt_size);
-		if (unlikely(cmnt_size == rrpc->dev->pgs_per_blk))
+		if (unlikely(cmnt_size == rrpc->dev->sec_per_blk))
 			rrpc_run_gc(rrpc, rblk);
 	}
 }
@@ -1014,6 +1024,7 @@ static int rrpc_l2p_update(u64 slba, u32 nlb, __le64 *entries, void *private)
 
 	for (i = 0; i < nlb; i++) {
 		u64 pba = le64_to_cpu(entries[i]);
+		unsigned int mod;
 		/* LNVM treats address-spaces as silos, LBA and PBA are
 		 * equally large and zero-indexed.
 		 */
@@ -1029,8 +1040,10 @@ static int rrpc_l2p_update(u64 slba, u32 nlb, __le64 *entries, void *private)
 		if (!pba)
 			continue;
 
+		div_u64_rem(pba, rrpc->nr_sects, &mod);
+
 		addr[i].addr = pba;
-		raddr[pba].addr = slba + i;
+		raddr[mod].addr = slba + i;
 	}
 
 	return 0;
@@ -1137,7 +1150,7 @@ static int rrpc_luns_init(struct rrpc *rrpc, int lun_begin, int lun_end)
 	struct rrpc_lun *rlun;
 	int i, j;
 
-	if (dev->pgs_per_blk > MAX_INVALID_PAGES_STORAGE * BITS_PER_LONG) {
+	if (dev->sec_per_blk > MAX_INVALID_PAGES_STORAGE * BITS_PER_LONG) {
 		pr_err("rrpc: number of pages per block too high.");
 		return -EINVAL;
 	}
@@ -1238,10 +1251,11 @@ static void rrpc_block_map_update(struct rrpc *rrpc, struct rrpc_block *rblk)
 	struct nvm_dev *dev = rrpc->dev;
 	int offset;
 	struct rrpc_addr *laddr;
-	u64 paddr, pladdr;
+	u64 bpaddr, paddr, pladdr;
 
-	for (offset = 0; offset < dev->pgs_per_blk; offset++) {
-		paddr = block_to_addr(rrpc, rblk) + offset;
+	bpaddr = block_to_rel_addr(rrpc, rblk);
+	for (offset = 0; offset < dev->sec_per_blk; offset++) {
+		paddr = bpaddr + offset;
 
 		pladdr = rrpc->rev_trans_map[paddr].addr;
 		if (pladdr == ADDR_EMPTY)
diff --git a/drivers/lightnvm/rrpc.h b/drivers/lightnvm/rrpc.h
index 3989d65..855f4a5 100644
--- a/drivers/lightnvm/rrpc.h
+++ b/drivers/lightnvm/rrpc.h
@@ -156,6 +156,15 @@ struct rrpc_rev_addr {
 	u64 addr;
 };
 
+static inline struct rrpc_block *rrpc_get_rblk(struct rrpc_lun *rlun,
+								int blk_id)
+{
+	struct rrpc *rrpc = rlun->rrpc;
+	int lun_blk = blk_id % rrpc->dev->blks_per_lun;
+
+	return &rlun->blocks[lun_blk];
+}
+
 static inline sector_t rrpc_get_laddr(struct bio *bio)
 {
 	return bio->bi_iter.bi_sector / NR_PHY_IN_LOG;
-- 
2.1.4