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| author | Bartosz Golaszewski <bartosz.golaszewski@linaro.org> | 2024-02-14 09:44:19 +0100 |
|---|---|---|
| committer | Bartosz Golaszewski <bartosz.golaszewski@linaro.org> | 2024-02-15 08:39:29 +0100 |
| commit | 0d7fa0eda4e3ffe1b7ebc73b6ef81298bddda649 (patch) | |
| tree | 36856d053c8c32ea85a5dd3689e0f901901dc6c5 /drivers/gpio | |
| parent | gpio: use srcu_dereference() with SRCU-protected pointers (diff) | |
| download | linux-0d7fa0eda4e3ffe1b7ebc73b6ef81298bddda649.tar.xz linux-0d7fa0eda4e3ffe1b7ebc73b6ef81298bddda649.zip | |
gpio: don't let lockdep complain about inherently dangerous RCU usage
There are two legacy, deprecated functions - gpiod_to_chip() and
gpio_device_get_chip() - that still have users in tree. They return the
address of the SRCU-protected chip outside of the read-only critical
sections. They are inherently dangerous and the users should convert to
safer alternatives. Let's explicitly silence lockdep warnings by using
rcu_dereference_check(ptr, 1). While at it: reuse
gpio_device_get_chip() in gpiod_to_chip().
Fixes: d83cee3d2bb1 ("gpio: protect the pointer to gpio_chip in gpio_device with SRCU")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202402122234.d85cca9b-lkp@intel.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Diffstat (limited to 'drivers/gpio')
| -rw-r--r-- | drivers/gpio/gpiolib.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index b095f475805f..02be0ba1a402 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -221,7 +221,8 @@ struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc) { if (!desc) return NULL; - return rcu_dereference(desc->gdev->chip); + + return gpio_device_get_chip(desc->gdev); } EXPORT_SYMBOL_GPL(gpiod_to_chip); @@ -291,7 +292,7 @@ EXPORT_SYMBOL(gpio_device_get_label); */ struct gpio_chip *gpio_device_get_chip(struct gpio_device *gdev) { - return rcu_dereference(gdev->chip); + return rcu_dereference_check(gdev->chip, 1); } EXPORT_SYMBOL_GPL(gpio_device_get_chip); |