[PATCH 1/4] driver core: Support two-pass driver shutdown

[Christoph Hellwig]

On Tue, Jan 02, 2024 at 10:07:30AM -0800, Jeremy Allison wrote:
>> But I'm not a workqueue expert and I do see the scary warning at
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/workqueue.h?id=v6.6#n619,
>> about not flushing system-wide workqueues, so maybe this wouldn't be
>> workable.
>
> This is a bigger change than I'm comfortable with
> (or indeed understand :-) right now. Can we fix
> the immediate problem first please and then look
> for improvements later ?

It's also a lot less efficient.  Assuming NVMe isn't alone and other
hardware interfaces also have a shutdown/disable busy wait (and I've seen
quite a few that do) as their limiting factor the two-pass shutdown seems
much nicer than spawning tons of work items.