md/raid5: fix raid5_set_bi_hw_segments

The @bio->bi_phys_segments consists of active stripes count in the
lower 16 bits and processed stripes count in the upper 16 bits. So
logical-OR operator should be bitwise one.

This bug has been present since 2.6.27 and the fix is suitable for any
-stable kernel since then.  Fortunately the bad code is only used on
error paths and is relatively unlikely to be hit.

Cc: stable@kernel.org
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index f9d2fbc64977eb0eea74e4e10f1a9125b4bef6ea..af8a9a89e4da9c1a19dad17ad5bd66ff8c48fad0 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -129,7 +129,7 @@ static inline int raid5_dec_bi_hw_segments(struct bio *bio)
 
 static inline void raid5_set_bi_hw_segments(struct bio *bio, unsigned int cnt)
 {
-       bio->bi_phys_segments = raid5_bi_phys_segments(bio) || (cnt << 16);
+       bio->bi_phys_segments = raid5_bi_phys_segments(bio) | (cnt << 16);
 }
 
 /* Find first data disk in a raid6 stripe */