linux-kernel - Re: [RFC PATCH] gpiolib: remove extra

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Date: Thu, 21 Dec 2023 19:50:16 +0100
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: Linus Walleij <linus.walleij@...aro.org>, Kent Gibson <warthog618@...il.com>, 
	linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [RFC PATCH] gpiolib: remove extra_checks

On Thu, Dec 21, 2023 at 5:13 PM Andy Shevchenko
<andriy.shevchenko@...ux.intel.com> wrote:
>
> On Thu, Dec 21, 2023 at 02:00:39PM +0100, Bartosz Golaszewski wrote:
> > On Thu, Dec 21, 2023 at 1:52 PM Andy Shevchenko
> > <andriy.shevchenko@...ux.intel.com> wrote:
> > > On Thu, Dec 21, 2023 at 10:26:03AM +0100, Bartosz Golaszewski wrote:
> > > > On Wed, Dec 20, 2023 at 4:28 PM Linus Walleij <linus.walleij@...aro.org> wrote:
>
> ...
>
> > > > Defining DEBUG makes sense to
> > > > enable dev_dbg() messages.
> > >
> > > Exactly!
> > >
> > > > CONFIG_DEBUG_GPIO is used by one driver
> > >
> > > By all drivers which are using pr_debug() / dev_dbg().
> > > I am using it a lot in my development process (actually I have it enabled
> > > in all my kernel configurations).
> >
> > I'm not saying we should remove it. It'll stay defined in the Makefile
> > and remain seamless for debug messages. I just want to get rid of that
> > ugly extra_checks variable which has very little impact.
>
> I agree that extra_checks is unusual (or as Linus put it "non-standard")
> thingy. And I agree that removal is for good.
>
> My question here solely about that WARN_ON(). Do we need it always be enabled
> or not?
>

I think it makes sense. If you're freeing a non-requested descriptor
then you clearly are doing something wrong and the system should yell.

Bart

> > > > to enable code that can lead to undefined behavior (should it maybe be
> > > > #if 0?).
> > >
> > > I don't know what you are talking about here.
> >
> > I'm talking about drivers/gpio/gpio-tps65219.c and its usage of
> > CONFIG_DEBUG_GPIO.
>
> Oh, that one should probably be
>
> #if 0
>         ...
> #endif
>
> or
>
>         if (0) {
>                 ...
>         }
>
> --
> With Best Regards,
> Andy Shevchenko
>
>