linux-kernel - Re: [PATCH 4/4] gpiolib: cdev: replace locking wrappers for gpio

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Message-ID: <CAMRc=MfvKzOxPrmz1wmgWMwYUbNhWAjqoKOmcaggQntcDprLmQ@mail.gmail.com>
Date: Wed, 20 Dec 2023 13:05:35 +0100
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Linus Walleij <linus.walleij@...aro.org>
Cc: Kent Gibson <warthog618@...il.com>, Peter Zijlstra <peterz@...radead.org>, 
	linux-kernel@...r.kernel.org, linux-gpio@...r.kernel.org, andy@...nel.org
Subject: Re: [PATCH 4/4] gpiolib: cdev: replace locking wrappers for
 gpio_device with guards

On Wed, Dec 20, 2023 at 12:56 PM Linus Walleij <linus.walleij@...aro.org> wrote:
>
> (+PeterZ)
>
> On Wed, Dec 20, 2023 at 2:52 AM Kent Gibson <warthog618@...il.com> wrote:
>
> > Replace the wrapping functions that inhibit removal of the gpio_device
> > with equivalent guard macros.
> >
> > Signed-off-by: Kent Gibson <warthog618@...il.com>
> (...)
> > +DEFINE_CLASS(_read_sem_guard,
> > +            struct rw_semaphore *,
> > +            up_read(_T),
> > +            ({
> > +               down_read(sem);
> > +               sem;
> > +            }),
> > +            struct rw_semaphore *sem);
>
> Isn't this so generic that it should be in <linux/cleanup.h>?
>
> Otherwise all the patches look good to me.
>

We already have this:

DEFINE_GUARD(rwsem_read, struct rw_semaphore *, down_read(_T), up_read(_T))
DEFINE_GUARD(rwsem_write, struct rw_semaphore *, down_write(_T), up_write(_T))

DEFINE_FREE(up_read, struct rw_semaphore *, if (_T) up_read(_T))
DEFINE_FREE(up_write, struct rw_semaphore *, if (_T) up_write(_T))

This can surely be used here, right?

Bart

> Yours,
> Linus Walleij