[PATCH 2/3] blk-mq: Provide freeze queue timeout

[Christoph Hellwig]

> +int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
> +				     unsigned long timeout)
> +{
> +	return wait_event_timeout(q->mq_freeze_wq,
> +					percpu_ref_is_zero(&q->q_usage_counter),
> +					timeout);
> +}
> +EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout);

Can you just add the timeout argument to blk_mq_freeze_queue_wait?
Existing callers can pass 0, which is interpreted as no timeout by
the low-level wait code.