[PATCH 3.19 018/101] Fix bug in blk_rq_merge_ok

Greg Kroah-Hartman
2015-04-17T13:35:49Z

From: Wenbo Wang <wenbo.wang@memblaze.com>

commit 7ee8e4f3983c4ff700958a6099c8fd212ea67b94 upstream.

Use the right array index to reference the last
element of rq->biotail->bi_io_vec[]

Signed-off-by: Wenbo Wang <wenbo.wang@memblaze.com>
Reviewed-by: Chong Yuan <chong.yuan@memblaze.com>
Fixes: 66cb45aa41315 ("block: add support for limiting gaps in SG lists")
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
block/blk-merge.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -609,7 +609,7 @@ bool blk_rq_merge_ok(struct request *rq,
if (q->queue_flags & (1 << QUEUE_FLAG_SG_GAPS)) {
struct bio_vec *bprev;

- bprev = &rq->biotail->bi_io_vec[bio->bi_vcnt - 1];
+ bprev = &rq->biotail->bi_io_vec[rq->biotail->bi_vcnt - 1];
if (bvec_gap_to_prev(bprev, bio->bi_io_vec[0].bv_offset))
return false;
}