[PATCH] blk-mq: put driver tag when this request is completed

[Ming Lei <ming.lei@redhat.com>]

It is natural to release driver tag when this request is completed by
LLD or device since its purpose is for LLD use.

One big benefit is that the released tag can be re-used quicker since
bio_endio() may take too long.

Meantime we don't need to release driver tag for flush request.

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 block/blk-flush.c | 6 ------
 block/blk-mq.c    | 2 ++
 2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/block/blk-flush.c b/block/blk-flush.c
index 15ae0155ec07..21108a550fbf 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -240,7 +240,6 @@ static void flush_end_io(struct request *flush_rq, blk_status_t error)
 		blk_mq_tag_set_rq(hctx, flush_rq->tag, fq->orig_rq);
 		flush_rq->tag = -1;
 	} else {
-		blk_mq_put_driver_tag(flush_rq);
 		flush_rq->internal_tag = -1;
 	}
 
@@ -341,11 +340,6 @@ static void mq_flush_data_end_io(struct request *rq, blk_status_t error)
 	unsigned long flags;
 	struct blk_flush_queue *fq = blk_get_flush_queue(q, ctx);
 
-	if (q->elevator) {
-		WARN_ON(rq->tag < 0);
-		blk_mq_put_driver_tag(rq);
-	}
-
 	/*
 	 * After populating an empty queue, kick it to avoid stall.  Read
 	 * the comment in flush_end_io().
diff --git a/block/blk-mq.c b/block/blk-mq.c
index b8738b3c6d06..d07e55455726 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -674,6 +674,8 @@ bool blk_mq_complete_request_remote(struct request *rq)
 {
 	WRITE_ONCE(rq->state, MQ_RQ_COMPLETE);
 
+	blk_mq_put_driver_tag(rq);
+
 	/*
 	 * For a polled request, always complete locallly, it's pointless
 	 * to redirect the completion.
-- 
2.25.2