linux-kernel - [PATCH v2 0/4] gpio: fix SRCU bugs

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Message-Id: <20240214084419.6194-1-brgl@bgdev.pl>
Date: Wed, 14 Feb 2024 09:44:15 +0100
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Linus Walleij <linus.walleij@...aro.org>,
	Kent Gibson <warthog618@...il.com>,
	Alex Elder <elder@...aro.org>,
	Geert Uytterhoeven <geert+renesas@...der.be>,
	"Paul E . McKenney" <paulmck@...nel.org>,
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
	Wolfram Sang <wsa@...-dreams.de>,
	Mark Brown <broonie@...nel.org>,
	Dan Carpenter <dan.carpenter@...aro.org>
Cc: linux-gpio@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: [PATCH v2 0/4] gpio: fix SRCU bugs

From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>

Here are four fixes to some bugs in recent SRCU changes. The first one fixes
an actual race condition. The other three just make lockdep happy.

v1 -> v2:
- use srcu_dereference() instead of rcu_dereference_protected() as
  advised by Paul
- add a patch using rcu_dereference_check(..., 1) in deprecated
  interfaces that return the address of the RCU-protected chip structure
  to external users (who shouldn't use it anyway but well...)
- pick up review tags for patches 1/4 and 2/4

Bartosz Golaszewski (4):
  gpio: take the SRCU read lock in gpiod_hog()
  gpio: cdev: use correct pointer accessors with SRCU
  gpio: use srcu_dereference() with SRCU-protected pointers
  gpio: don't let lockdep complain about inherently dangerous RCU usage

 drivers/gpio/gpiolib-cdev.c  | 25 ++++++++++++-------------
 drivers/gpio/gpiolib-sysfs.c |  5 +++--
 drivers/gpio/gpiolib.c       | 32 ++++++++++++++++++--------------
 drivers/gpio/gpiolib.h       |  3 ++-
 4 files changed, 35 insertions(+), 30 deletions(-)

-- 
2.40.1