From: Ming Lei <ming.lei@redhat.com>
Date: Mon, 29 Jun 2020 17:47:59 +0800
Subject: [PATCH] blk-mq: put driver tag when this request is completed
References: bsc#1175995,jsc#SLE-15608
Git-commit: 36a3df5a4574d5ddf59804fcd0c4e9654c514d9a
Patch-mainline: v5.9-rc1

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.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 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 a600b0a64caf..0b5f0d2b3c4c 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 c56871214fd5..7b10c147bd83 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -660,6 +660,8 @@ void blk_mq_force_complete_rq(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.
-- 
2.16.4