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authorJavier González <javier@cnexlabs.com>2017-10-13 14:46:17 +0200
committerJens Axboe <axboe@kernel.dk>2017-10-13 08:34:57 -0600
commit6ca2f71f3e3d94d188000b420ce0529b07f3ce95 (patch)
treee99c846fd3bbbd5786e41425371584763abe0d0a
parent55e836d401601e7903b36db015ce899dc11085ab (diff)
lightnvm: pblk: simplify path on REQ_PREFLUSH
On REQ_PREFLUSH, directly tag the I/O context flags to signal a flush in the write to cache path, instead of finding the correct entry context and imposing a memory barrier. This simplifies the code and might potentially prevent race conditions when adding functionality to the write path. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--drivers/lightnvm/pblk-cache.c4
-rw-r--r--drivers/lightnvm/pblk-rb.c8
2 files changed, 4 insertions, 8 deletions
diff --git a/drivers/lightnvm/pblk-cache.c b/drivers/lightnvm/pblk-cache.c
index 1d6b8e3585f1..0d227ef7d1b9 100644
--- a/drivers/lightnvm/pblk-cache.c
+++ b/drivers/lightnvm/pblk-cache.c
@@ -43,8 +43,10 @@ retry:
if (unlikely(!bio_has_data(bio)))
goto out;
- w_ctx.flags = flags;
pblk_ppa_set_empty(&w_ctx.ppa);
+ w_ctx.flags = flags;
+ if (bio->bi_opf & REQ_PREFLUSH)
+ w_ctx.flags |= PBLK_FLUSH_ENTRY;
for (i = 0; i < nr_entries; i++) {
void *data = bio_data(bio);
diff --git a/drivers/lightnvm/pblk-rb.c b/drivers/lightnvm/pblk-rb.c
index 74c768ce09ef..05e6b2e9221d 100644
--- a/drivers/lightnvm/pblk-rb.c
+++ b/drivers/lightnvm/pblk-rb.c
@@ -355,7 +355,6 @@ static int pblk_rb_sync_point_set(struct pblk_rb *rb, struct bio *bio,
{
struct pblk_rb_entry *entry;
unsigned int subm, sync_point;
- int flags;
subm = READ_ONCE(rb->subm);
@@ -369,12 +368,6 @@ static int pblk_rb_sync_point_set(struct pblk_rb *rb, struct bio *bio,
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);
@@ -454,6 +447,7 @@ static int pblk_rb_may_write_flush(struct pblk_rb *rb, unsigned int nr_entries,
/* Protect from read count */
smp_store_release(&rb->mem, mem);
+
return 1;
}