Re: [PATCH v6] ath9k: sleep for less time when unregistering hwrng

[Jason A. Donenfeld]

Hi Herbert,

On Tue, Jun 28, 2022 at 12:52 PM Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Tue, Jun 28, 2022 at 12:48:50PM +0200, Jason A. Donenfeld wrote:
> >
> > $ curl https://lore.kernel.org/lkml/20220627104955.534013-1-Jason@xxxxxxxxx/raw
> > | git am
> >
> > That one, if you want to give it a spin and see if that 5-6s is back
> > to ~1s or less.
>
> Whatever caused kthread_should_stop to return true should have
> woken the thread and caused schedule_timeout to return.
>
> If it's not waking the thread up then we should find out why.
>
> Oh wait you're checking kthread_should_stop before the schedule
> call instead of afterwards, that would do it.

Oh, that's a really good observation, thank you! I'll send a patch
that does it right. I have to check kthread_should_stop() before,
because the wake up might have been consumed by a sleep inside of the
hwrng ->read_data() function, causing it to return early. So we have
to check it before going to sleep again. And after, I need to be
checking the return value of schedule_timeout_interruptible(), which
I'm not in this latest. So v+1 coming up.

By the way, this thread might interest you:
https://lore.kernel.org/lkml/20220627145716.641185-1-Jason@xxxxxxxxx/

Jason