From: John Garry <john.garry@huawei.com>
Date: Thu, 16 Apr 2020 19:18:51 +0800
Subject: blk-mq: Put driver tag in blk_mq_dispatch_rq_list() when no budget
Patch-mainline: v5.7-rc2
Git-commit: 5fe56de799ad03e92d794c7936bf363922b571df
References: bsc#1180092

If in blk_mq_dispatch_rq_list() we find no budget, then we break of the
dispatch loop, but the request may keep the driver tag, evaulated
in 'nxt' in the previous loop iteration.

Fix by putting the driver tag for that request.

Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Martin Wilck <mwilck@suse.com>
---
 block/blk-mq.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1232,8 +1232,10 @@ bool blk_mq_dispatch_rq_list(struct requ
 		rq = list_first_entry(list, struct request, queuelist);
 
 		hctx = rq->mq_hctx;
-		if (!got_budget && !blk_mq_get_dispatch_budget(hctx))
+		if (!got_budget && !blk_mq_get_dispatch_budget(hctx)) {
+			blk_mq_put_driver_tag(rq);
 			break;
+		}
 
 		if (!blk_mq_get_driver_tag(rq)) {
 			/*