blk-mq: Put driver tag in blk_mq_dispatch_rq_list() when no budget

[ Upstream commit 5fe56de799ad03e92d794c7936bf363922b571df ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 37ff8dfb8ab9fc542d7b9284e40817dee47862f9..2c3a1b2e0753756bd3d89713e96e6c3eff0af9c0 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1205,8 +1205,10 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
                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)) {
                        /*