On Wed, Aug 31, 2022 at 12:01:53AM +0900, Suwan Kim wrote:
> If a request fails at virtio_queue_rqs(), it is inserted to requeue_list
> and passed to virtio_queue_rq(). Then blk_mq_start_request() can be called
> again at virtio_queue_rq() and trigger WARN_ON_ONCE like below trace because
> request state was already set to MQ_RQ_IN_FLIGHT in virtio_queue_rqs()
> despite the failure.
>
> To avoid calling blk_mq_start_request() twice, This patch moves the
> execution of blk_mq_start_request() to the end of virtblk_prep_rq().
> And instead of requeuing failed request to plug list in the error path of
> virtblk_add_req_batch(), it uses blk_mq_requeue_request() to change failed
> request state to MQ_RQ_IDLE. Then virtblk can safely handle the request
> on the next trial.
>
> Fixes: 0e9911fa768f ("virtio-blk: support mq_ops->queue_rqs()")
> Reported-by: Alexandre Courbot <acourbot@xxxxxxxxxxxx>
> Tested-by: Alexandre Courbot <acourbot@xxxxxxxxxxxx>
> Signed-off-by: Suwan Kim <suwan.kim027@xxxxxxxxx>
> ---
Looks good.
Reviewed-by: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
