4.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ming Lei <ming....@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.vale...@linaro.org>
Cc: Omar Sandoval <osan...@fb.com>
Fixes: bd166ef183c2 ("blk-mq-sched: add framework for MQ capable IO schedulers")
Cc: sta...@vger.kernel.org
Reviewed-by: Bart Van Assche <bart.vanass...@wdc.com>
Acked-by: Paolo Valente <paolo.vale...@linaro.org>
Signed-off-by: Ming Lei <ming....@redhat.com>
Signed-off-by: Jens Axboe <ax...@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

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

--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -655,7 +655,6 @@ 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))
@@ -667,6 +666,9 @@ 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);
 }


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