lightnvm: pblk: simplify data validity check on GC

When a line is selected for recycling by the garbage collector (GC), the
line state changes and the invalid bitmap is frozen, preventing
invalidations from happening. Throughout the GC, the L2P map is checked
to verify that not data being recycled has been updated. The last check
is done before the new map is being stored on the L2P table. Though
this algorithm works, it requires a number of corner cases to be checked
each time the L2P table is being updated. This complicates readability
and is error prone in case that the recycling algorithm is modified.

Instead, this patch makes the invalid bitmap accessible even when the
line is being recycled. When recycled data is being remapped, it is
enough to check the invalid bitmap for the line before updating the L2P
table.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 10 insertions, 10 deletions

diff --git a/drivers/lightnvm/pblk-cache.c b/drivers/lightnvm/pblk-cache.c
index 024a8fc93069..1d6b8e3585f1 100644
--- a/drivers/lightnvm/pblk-cache.c
+++ b/drivers/lightnvm/pblk-cache.c
@@ -73,12 +73,11 @@ out:
  * 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)
+int pblk_write_gc_to_cache(struct pblk *pblk, struct pblk_gc_rq *gc_rq)
 {
 	struct pblk_w_ctx w_ctx;
 	unsigned int bpos, pos;
+	void *data = gc_rq->data;
 	int i, valid_entries;
 
 	/* Update the write buffer head (mem) with the entries that we can
@@ -86,28 +85,29 @@ int pblk_write_gc_to_cache(struct pblk *pblk, void *data, u64 *lba_list,
 	 * rollback from here on.
 	 */
 retry:
-	if (!pblk_rb_may_write_gc(&pblk->rwb, nr_rec_entries, &bpos)) {
+	if (!pblk_rb_may_write_gc(&pblk->rwb, gc_rq->secs_to_gc, &bpos)) {
 		io_schedule();
 		goto retry;
 	}
 
-	w_ctx.flags = flags;
+	w_ctx.flags = PBLK_IOTYPE_GC;
 	pblk_ppa_set_empty(&w_ctx.ppa);
 
-	for (i = 0, valid_entries = 0; i < nr_entries; i++) {
-		if (lba_list[i] == ADDR_EMPTY)
+	for (i = 0, valid_entries = 0; i < gc_rq->nr_secs; i++) {
+		if (gc_rq->lba_list[i] == ADDR_EMPTY)
 			continue;
 
-		w_ctx.lba = lba_list[i];
+		w_ctx.lba = gc_rq->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);
+		pblk_rb_write_entry_gc(&pblk->rwb, data, w_ctx, gc_rq->line,
+						gc_rq->paddr_list[i], pos);
 
 		data += PBLK_EXPOSED_PAGE_SIZE;
 		valid_entries++;
 	}
 
-	WARN_ONCE(nr_rec_entries != valid_entries,
+	WARN_ONCE(gc_rq->secs_to_gc != valid_entries,
 					"pblk: inconsistent GC write\n");
 
 #ifdef CONFIG_NVM_DEBUG