[PATCH 0/2] gpiolib: use a read-write semaphore to protect the GPIO device list

From: Bartosz Golaszewski
Date: Thu Dec 21 2023 - 13:43:33 EST


From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>

I'm still figuring out how to keep GPIO descriptors coherent while
(mostly) lockless. In the meantime, I found a potential race-condition
during GPIO descriptor lookup and also figured that the correct way to
protect the GPIO device list is actually a read-write semaphore as we're
not modifying the list very often and readers should be able to iterate
over it concurrently.

Bartosz Golaszewski (2):
gpiolib: replace the GPIO device mutex with a read-write semaphore
gpiolib: pin GPIO devices in place during descriptor lookup

drivers/gpio/gpiolib-sysfs.c | 2 +-
drivers/gpio/gpiolib.c | 58 ++++++++++++++++++++----------------
drivers/gpio/gpiolib.h | 2 +-
3 files changed, 34 insertions(+), 28 deletions(-)

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2.40.1