Received-SPF: pass (google.com: domain of linux-kernel+bounces-64335-linux.lists.archive=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99;
Precedence: bulk
MIME-Version: 1.0
References: <20240213093108.13922-1-brgl@bgdev.pl> <20240213093108.13922-3-brgl@bgdev.pl>
In-Reply-To: <20240213093108.13922-3-brgl@bgdev.pl>
From: Linus Walleij <linus.walleij@linaro.org>
Date: Tue, 13 Feb 2024 22:33:46 +0100
Message-ID: <CACRpkdYbfU3LV=+xEiE=+MN4xc-_zc_6WiNOP84_PzqttCsQTA@mail.gmail.com>
Subject: Re: [PATCH 2/3] gpio: cdev: use correct pointer accessors with SRCU
To: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Kent Gibson <warthog618@gmail.com>, Alex Elder <elder@linaro.org>, 
	Geert Uytterhoeven <geert+renesas@glider.be>, "Paul E . McKenney" <paulmck@kernel.org>, 
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>, Wolfram Sang <wsa@the-dreams.de>, 
	linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, 
	Bartosz Golaszewski <bartosz.golaszewski@linaro.org>, kernel test robot <oliver.sang@intel.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

On Tue, Feb 13, 2024 at 10:31=E2=80=AFAM Bartosz Golaszewski <brgl@bgdev.pl=
> wrote:

> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>
> We never dereference the chip pointer in character device code so we can
> use the lighter rcu_access_pointer() helper. This also makes lockep
> happier as it no longer complains about suspicious rcu_dereference()
> usage.
>
> Fixes: d83cee3d2bb1 ("gpio: protect the pointer to gpio_chip in gpio_devi=
ce with SRCU")
> Reported-by: kernel test robot <oliver.sang@intel.com>
> Closes: https://lore.kernel.org/oe-lkp/202402122234.d85cca9b-lkp@intel.co=
m
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

I had to check what rcu_access_pointer() does and it's clearly the
right thing to do so:
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij