This is a note to let you know that I've just added the patch titled

blk-mq: don't call io sched's .requeue_request when requeueing rq to ->dispatch

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: blk-mq-don-t-call-io-sched-s-.requeue_request-when-requeueing-rq-to-dispatch.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 105976f517791aed3b11f8f53b308a2069d42055 Mon Sep 17 00:00:00 2001

From: Ming Lei ming.lei@redhat.com Date: Fri, 23 Feb 2018 23:36:56 +0800 Subject: blk-mq: don't call io sched's .requeue_request when requeueing rq to ->dispatch

From: Ming Lei ming.lei@redhat.com

commit 105976f517791aed3b11f8f53b308a2069d42055 upstream.

__blk_mq_requeue_request() covers two cases:

- one is that the requeued request is added to hctx->dispatch, such as blk_mq_dispatch_rq_list()

- another case is that the request is requeued to io scheduler, such as blk_mq_requeue_request().

We should call io sched's .requeue_request callback only for the 2nd case.

Cc: Paolo Valente paolo.valente@linaro.org Cc: Omar Sandoval osandov@fb.com Fixes: bd166ef183c2 ("blk-mq-sched: add framework for MQ capable IO schedulers") Cc: stable@vger.kernel.org Reviewed-by: Bart Van Assche bart.vanassche@wdc.com Acked-by: Paolo Valente paolo.valente@linaro.org Signed-off-by: Ming Lei ming.lei@redhat.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- block/blk-mq.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -638,7 +638,6 @@ static void __blk_mq_requeue_request(str

trace_block_rq_requeue(q, rq); wbt_requeue(q->rq_wb, &rq->issue_stat); - blk_mq_sched_requeue_request(rq);

if (test_and_clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) { if (q->dma_drain_size && blk_rq_bytes(rq)) @@ -650,6 +649,9 @@ void blk_mq_requeue_request(struct reque { __blk_mq_requeue_request(rq);

+ /* this request will be re-inserted to io scheduler queue */ + blk_mq_sched_requeue_request(rq); + BUG_ON(blk_queued_rq(rq)); blk_mq_add_to_requeue_list(rq, true, kick_requeue_list); }

Patches currently in stable-queue which might be from ming.lei@redhat.com are

queue-4.14/blk-mq-don-t-call-io-sched-s-.requeue_request-when-requeueing-rq-to-dispatch.patch queue-4.14/block-kyber-fix-domain-token-leak-during-requeue.patch