Fix bug in blk_rq_merge_ok

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")
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/blk-merge.c b/block/blk-merge.c
index fc1ff3b1ea1f4a9ea2dcd18d6e49eea7281eb9b3..fd3fee81c23ce2f1cdc73d2bf4e76188c90358cb 100644 (file)
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -592,7 +592,7 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
        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;
        }