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

Message ID 20231221184316.24506-1-brgl@bgdev.pl
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Series gpiolib: use a read-write semaphore to protect the GPIO device list | expand

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Bartosz Golaszewski Dec. 21, 2023, 6:43 p.m. UTC 
From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

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(-)