Re: [PATCH] irqchip: stm32: add a second level init to request hwspinlock

From: Marc Zyngier
Date: Thu Mar 07 2019 - 11:44:28 EST

On 07/03/2019 16:23, Fabien Dessenne wrote:
> Requesting hwspinlock, at the first time it is used, is not correct:
> indeed, at that moment we are under raw_spin_lock_irqsave() context and
> hwspin_lock_request_specific() may sleep ("BUG: sleeping function called
> from invalid context").
> Requesting hwspinlock during the init (stm32*_exti_of_init()) is also
> not possible (the hwspinlock framework is not ready at that stage of the
> kernel init).
> As a consequence, add a second level init (probed with arch_initcall)
> where we can safely request hwspinlock.

No, this is fairly broken. You're playing with stuff you're not supposed
to (OF_POPULATE? really?), and adding initcalls is completely unreliable
(things depend on the link order and will randomly break).

If you need dependencies, implement them correctly. Turn this driver
into a real device driver (in the platform device sense), and return
PROBE_DEFER when you can't find your dependency.


Jazz is not dead. It just smells funny...