On Fri, Jan 20, 2023 at 07:59:34AM -0700, Jens Axboe wrote:
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -869,7 +869,16 @@ int bio_poll(struct bio *bio, struct io_comp_batch *iob, unsigned int flags)
> */
> blk_flush_plug(current->plug, false);
>
> - if (bio_queue_enter(bio))
> + /*
> + * We need to be able to enter a frozen queue, similar to how
> + * timeouts also need to do that. If that is blocked, then we can
> + * have pending IO when a queue freeze is started, and then the
> + * wait for the freeze to finish will wait for polled requests to
> + * timeout as the poller is preventer from entering the queue and
> + * completing them. As long as we prevent new IO from being queued,
> + * that should be all that matters.
> + */
> + if (!percpu_ref_tryget(&q->q_usage_counter))
> return 0;
> if (queue_is_mq(q)) {
> ret = blk_mq_poll(q, cookie, iob, flags);
Looks good!
Reviewed-by: Keith Busch <kbusch@xxxxxxxxxx>
