From: =?UTF-8?q?Javier=20Gonz=C3=A1lez?= <javier@cnexlabs.com>
Date: Fri, 13 Oct 2017 14:46:17 +0200
Subject: [PATCH] lightnvm: pblk: simplify path on REQ_PREFLUSH
Git-commit: 6ca2f71f3e3d94d188000b420ce0529b07f3ce95
Patch-mainline: v4.15-rc1
References: bsc#1104967,FATE#325924
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
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>
Acked-by: Hannes Reinecke <hare@suse.com>
---
drivers/lightnvm/pblk-cache.c | 4 +++-
drivers/lightnvm/pblk-rb.c | 8 +-------
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 @@ int pblk_write_to_cache(struct pblk *pblk, struct bio *bio, unsigned long flags)
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;
}
--
2.12.3