This is a note to let you know that I've just added the patch titled
blk-mq: Put driver tag in blk_mq_dispatch_rq_list() when no budget
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
blk-mq-put-driver-tag-in-blk_mq_dispatch_rq_list-whe.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 37985cd9e91d1869a259f120e48f7a1403370f91
Author: John Garry <john.garry@xxxxxxxxxx>
Date: Thu Apr 16 19:18:51 2020 +0800
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@xxxxxxxxxx>
Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/block/blk-mq.c b/block/blk-mq.c
index a8c1a45cedde0..757c0fd9f0cc2 100644
--- 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)) {
/*
