block: use proper BLK_RW_ASYNC in blk_queue_start_tag()

Makes it easier to read than the 0.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/block/blk-tag.c b/block/blk-tag.c
index 2e5cfeb59333..6b0f52c20964 100644
--- a/block/blk-tag.c
+++ b/block/blk-tag.c
@@ -359,7 +359,7 @@ int blk_queue_start_tag(struct request_queue *q, struct request *rq)
                 max_depth -= 2;
                 if (!max_depth)
                         max_depth = 1;
-                if (q->in_flight[0] > max_depth)
+                if (q->in_flight[BLK_RW_ASYNC] > max_depth)
                         return 1;
         }