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 a8c1a45..757c0fd 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1232,8 +1232,10 @@ 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)) {
                        /*