Re: [PATCH 03/23] gpio: sysfs: drop redundant lock-as-irq

From: Johan Hovold
Date: Thu Apr 30 2015 - 05:08:05 EST

On Wed, Apr 29, 2015 at 11:48:57PM +0200, Linus Walleij wrote:
> On Tue, Apr 21, 2015 at 5:42 PM, Johan Hovold <johan@xxxxxxxxxx> wrote:
> > Drop redundant lock-as-irq in gpio_setup_irq, which has already been
> > handled when requesting and releasing the irq (i.e. in the irq chip
> > irq_request_resources and irq_release_resources callbacks).
> Well we would hope they all do that. And I hope for the vast majority
> that is true, but there is a TODO to go over all gpiochip drivers
> (some which are elsewhere in the kernel than drivers/gpio) and
> make sure they actually do so.
> Right now it's a bit arbitrary if so happens, and in not marked by
> the driver as IRQ then this kicks in and provides an additional
> protection.
> But maybe that's overzealous, what do people say?

No, you're right. The drivers that fail to do this needs to be fixed,
but the "redundant" lock-as-irq in the sysfs interface should not be
removed before that.

I'll respin the series and add it back with a comment explaining why
gpiochip_lock_as_irq is currently called twice.

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