> > So I think there is a redundant call to blk_freeze_queue_start(), we
> > just need to call blk_mq_freeze_queue_wait() after calling
> > blk_queue_start_drain().
>
> I think it is on purpose that blk_queue_start_drain() freezes the
> request queue and never unfreezes it. So if you want to change this
> behavior it's up to you to motivate why you want to change this behavior
> and also why it is safe to make that change. See also commit
> d3cfb2a0ac0b ("block: block new I/O just after queue is set as dying").
>
> Bart.
I think there might be some misunderstanding. I didn't touch
blk_queue_start_drain(), so its behavior is not changed. What I have done
is just replacing blk_freeze_queue() with blk_mq_freeze_queue_wait() in
blk_mq_destroy_queue().
See:
- https://lore.kernel.org/linux-block/20221030084011.GA5262@xxxxxx/T/#t
Thanks!
Jinlong Chen
