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authorNeilBrown <neilb@suse.com>2017-03-15 06:05:13 +0300
committerShaohua Li <shli@fb.com>2017-03-23 05:16:30 +0300
commit016c76ac76e4c678b01a75a602dc6be0282f5b29 (patch)
treeed943bdfc80ab4ff7aa3228023f6f0dc0c0992fa /drivers/md/raid5.h
parentbd83d0a28c68bacba88a3193a1bd6a083bb8d9f5 (diff)
downloadlinux-016c76ac76e4c678b01a75a602dc6be0282f5b29.tar.xz
md/raid5: use bio_inc_remaining() instead of repurposing bi_phys_segments as a counter
md/raid5 needs to keep track of how many stripe_heads are processing a bio so that it can delay calling bio_endio() until all stripe_heads have completed. It currently uses 16 bits of ->bi_phys_segments for this purpose. 16 bits is only enough for 256M requests, and it is possible for a single bio to be larger than this, which causes problems. Also, the bio struct contains a larger counter, __bi_remaining, which has a purpose very similar to the purpose of our counter. So stop using ->bi_phys_segments, and instead use __bi_remaining. This means we don't need to initialize the counter, as our caller initializes it to '1'. It also means we can call bio_endio() directly as it tests this counter internally. Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md/raid5.h')
-rw-r--r--drivers/md/raid5.h17
1 files changed, 1 insertions, 16 deletions
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index fd5c21cde77f..7d74fb3f2ec6 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -488,8 +488,7 @@ static inline struct bio *r5_next_bio(struct bio *bio, sector_t sector)
}
/*
- * We maintain a biased count of active stripes in the bottom 16 bits of
- * bi_phys_segments, and a count of processed stripes in the upper 16 bits
+ * We maintain a count of processed stripes in the upper 16 bits
*/
static inline int raid5_bi_processed_stripes(struct bio *bio)
{
@@ -498,20 +497,6 @@ static inline int raid5_bi_processed_stripes(struct bio *bio)
return (atomic_read(segments) >> 16) & 0xffff;
}
-static inline int raid5_dec_bi_active_stripes(struct bio *bio)
-{
- atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
-
- return atomic_sub_return(1, segments) & 0xffff;
-}
-
-static inline void raid5_inc_bi_active_stripes(struct bio *bio)
-{
- atomic_t *segments = (atomic_t *)&bio->bi_phys_segments;
-
- atomic_inc(segments);
-}
-
static inline void raid5_set_bi_processed_stripes(struct bio *bio,
unsigned int cnt)
{