[PATCH v2 3/5] ath10k: drain tx before restarting hw

[Kalle Valo]

Michal Kazior <michal.kazior at tieto.com> writes:

>> Sure, but I still think it's a bit ugly. The right way to fix this would
>> be to add it to include/lockdep.h, instead of adding custom checks to a
>> driver.
>
> Good point. I wonder if it's generic enough to justify.

No idea. But no matter what it will take some time to get it accepted,
so we need to solve this in a faster way so that I can apply this patch.

>> But does this check even make sense? There's nothing preventing
>> to another thread to take lock just after the WARN_ON(), right?
>
> There's nothing wrong with other thread holding it. Actually that's
> the reason for this very check.
>
> The point is to prevent ath10k_drain_tx() being called while caller
> (current thread) holds conf_mutex. If it were to hold conf_mutex then
> cancel_work_sync() can deadlock as both workers it tries to stop try
> to get a hold of the lock too.

Ah, now I understand.

What if we just drop the WARN_ON() from this patch just so that I can
apply the patch and we add a proper code for checking the mutex in a
followup patch? Are you ok with that?


-- 
Kalle Valo