Hi, Bart.
> > Calling blk_freeze_queue results in a redundant call to
> > blk_freeze_queue_start as it has been called in blk_queue_start_drain.
> >
> > Replace blk_freeze_queue with blk_mq_freeze_queue_wait to avoid the
> > redundant call.
>
> blk_mq_destroy_queue() has more callers than blk_queue_start_drain() so
> the above description is at least misleading.
>
> Additionally, the word "cleanup" from the patch series title indicates
> that no patch in this series changes the behavior of the code. This
> patch involves a behavior change.
Sorry for my poor description. I'll send a new series with these
description problems resolved.
> I think this patch introduces a hang for every caller of
> blk_mq_destroy_queue() other than blk_queue_start_drain().
>
> Bart.
I don't see why the patch introduces a hang. The calling relationship in
blk_mq_destroy_queue is as follows:
blk_mq_destroy_queue()
...
-> blk_queue_start_drain()
-> blk_freeze_queue_start() <- called
...
-> blk_freeze_queue()
-> blk_freeze_queue_start() <- called again
-> blk_mq_freeze_queue_wait()
...
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().
Thanks!
Jinlong Chen
