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>

diff --git a/block/blk-tag.c b/block/blk-tag.c
index 2e5cfeb..6b0f52c 100644 (file)
--- 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;
        }