Patch "bcache: fix wrong cache_misses statistics" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

bcache: fix wrong cache_misses statistics

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
bcache-fix-wrong-cache_misses-statistics.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: "tang.junhui" <[email protected]>
Date: Mon, 30 Oct 2017 14:46:34 -0700
Subject: bcache: fix wrong cache_misses statistics

From: "tang.junhui" <[email protected]>

[ Upstream commit c157313791a999646901b3e3c6888514ebc36d62 ]

Currently, Cache missed IOs are identified by s->cache_miss, but actually, there are many situations that missed IOs are not assigned a value for s->cache_miss in cached_dev_cache_miss(), for example, a bypassed IO (s->iop.bypass = 1), or the cache_bio allocate failed. In these situations, it will go to out_put or out_submit, and s->cache_miss is null, which leads bch_mark_cache_accounting() to treat this IO as a hit IO.

[ML: applied by 3-way merge]

---
 drivers/md/bcache/request.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

@@ -463,6 +463,7 @@ struct search {
 	unsigned		recoverable:1;
 	unsigned		write:1;
 	unsigned		read_dirty_data:1;
+	unsigned		cache_missed:1;
 
 	unsigned long		start_time;
 

@@ -649,6 +650,7 @@ static inline struct search *search_allo
 
 	s->orig_bio		= bio;
 	s->cache_miss		= NULL;
+	s->cache_missed		= 0;
 	s->d			= d;
 	s->recoverable		= 1;
 	s->write		= op_is_write(bio_op(bio));

@@ -767,7 +769,7 @@ static void cached_dev_read_done_bh(stru
 	struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
 
 	bch_mark_cache_accounting(s->iop.c, s->d,
-				  !s->cache_miss, s->iop.bypass);
+				  !s->cache_missed, s->iop.bypass);
 	trace_bcache_read(s->orig_bio, !s->cache_miss, s->iop.bypass);
 
 	if (s->iop.status)

@@ -786,6 +788,8 @@ static int cached_dev_cache_miss(struct
 	struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
 	struct bio *miss, *cache_bio;
 
+	s->cache_missed = 1;
+
 	if (s->cache_miss || s->iop.bypass) {
 		miss = bio_next_split(bio, sectors, GFP_NOIO, s->d->bio_split);
 		ret = miss == bio ? MAP_DONE : MAP_CONTINUE;

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/bcache-fix-wrong-cache_misses-statistics.patch