Re: [PATCH v3] blk-mq: punt failed direct issue to dispatch list

[Bart Van Assche <bvanassche@acm.org>]

On Fri, 2018-12-07 at 09:35 -0700, Jens Axboe wrote:
> diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
> index 29bfe8017a2d..9e5bda8800f8 100644
> --- a/block/blk-mq-sched.c
> +++ b/block/blk-mq-sched.c
> @@ -377,6 +377,16 @@ void blk_mq_sched_insert_request(struct request *rq, bool at_head,
>  
>  	WARN_ON(e && (rq->tag != -1));
>  
> +	/*
> +	 * It's illegal to insert a request into the scheduler that has
> +	 * been through ->queue_rq(). Warn for that case, and use a bypass
> +	 * insert to be safe.
> +	 */

Shouldn't this refer to requests that have been prepared instead of requests
that have been through ->queue_rq()? I think this function is called for
requests that are requeued. Requeued requests have been through ->queue_rq()
but are unprepared before being requeued.

Thanks,

Bart.