[PATCH v2 0/6] gpio: cdev: bail out of poll() if the device goes down

From: Bartosz Golaszewski
Date: Thu Aug 17 2023 - 14:51:05 EST


From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>

Wake up all three wake queues (the one associated with the character
device file, the one for V1 line events and the V2 line request one)
when the underlying GPIO device is unregistered. This way we won't get
stuck in poll() after the chip is gone as user-space will be forced to
go back into a new system call and will see that gdev->chip is NULL.

v1 -> v2:
- not much is left from v1, this time we don't repurpose the existing
gpio_device notifier but add a new one so that cdev structures don't
get unwanted events

Bartosz Golaszewski (6):
gpiolib: rename the gpio_device notifier
gpio: cdev: open-code to_gpio_chardev_data()
gpiolib: add a second blocking notifier to struct gpio_device
gpio: cdev: wake up chardev poll() on device unbind
gpio: cdev: wake up linereq poll() on device unbind
gpio: cdev: wake up lineevent poll() on device unbind

drivers/gpio/gpiolib-cdev.c | 101 ++++++++++++++++++++++++++++++------
drivers/gpio/gpiolib.c | 7 +--
drivers/gpio/gpiolib.h | 9 ++--
3 files changed, 94 insertions(+), 23 deletions(-)

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2.39.2