blk-mq: blk_mq_tag_to_rq should handle flush request

flush request is special, which borrows the tag from the parent
request. Hence blk_mq_tag_to_rq needs special handling to return
the flush request from the tag.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/block/blk-flush.c b/block/blk-flush.c
index ef608b35d9be..ff87c664b7df 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -223,8 +223,10 @@ static void flush_end_io(struct request *flush_rq, int error)
         struct request *rq, *n;
         unsigned long flags = 0;
 
-        if (q->mq_ops)
+        if (q->mq_ops) {
                 spin_lock_irqsave(&q->mq_flush_lock, flags);
+                q->flush_rq->cmd_flags = 0;
+        }
 
         running = &q->flush_queue[q->flush_running_idx];
         BUG_ON(q->flush_pending_idx == q->flush_running_idx);