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efb8235bfd
This reverts commits1979a28075("gpiolib: replace the GPIO device mutex with a read-write semaphore") and65a828bab1("gpiolib: use a mutex to protect the list of GPIO devices"). Unfortunately the legacy GPIO API that's still used in older code has to translate numbers from the global GPIO numberspace to descriptors. This results in a GPIO device lookup in every call to legacy functions. Some of those functions - like gpio_set/get_value() - can be called from atomic context so taking a sleeping lock that is an RW semaphore results in an error. We'll probably have to protect this list with SRCU. Reported-by: Dan Carpenter <dan.carpenter@linaro.org> Closes: https://lore.kernel.org/linux-wireless/f7b5ff1e-8f34-4d98-a7be-b826cb897dc8@moroto.mountain/ Fixes:1979a28075("gpiolib: replace the GPIO device mutex with a read-write semaphore") Fixes:65a828bab1("gpiolib: use a mutex to protect the list of GPIO devices") Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Linux kernel
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