linux.git/drivers/gpio/gpiolib-cdev.c, branch v6.8

gpiolib: cdev: replace locking wrappers for gpio_device with guards

2023-12-27T14:45:45+00:00

Replace the wrapping functions that inhibit removal of the gpio chip
with equivalent guards.

Signed-off-by: Kent Gibson 
Signed-off-by: Bartosz Golaszewski

gpiolib: cdev: replace locking wrappers for config_mutex with guards

2023-12-27T14:45:30+00:00

After the adoption of guard(), the locking wrappers that hold the
config_mutex for linereq_set_values() and linereq_set_config() no
longer add value, so combine them into the functions they wrap.

Signed-off-by: Kent Gibson 
Signed-off-by: Bartosz Golaszewski

gpiolib: cdev: allocate linereq using kvzalloc()

2023-12-27T14:43:56+00:00

The size of struct linereq may exceed a page, so allocate space for
it using kvzalloc() instead of kzalloc() to handle the case where
memory is heavily fragmented and kzalloc() cannot find a sufficient
contiguous region.

Signed-off-by: Kent Gibson 
Signed-off-by: Bartosz Golaszewski

gpiolib: cdev: include overflow.h

2023-12-27T14:43:40+00:00

struct_size() is used to calculate struct linereq size, so explicitly
include overflow.h.

Signed-off-by: Kent Gibson 
Signed-off-by: Bartosz Golaszewski

Merge tag 'v6.7-rc7' into gpio/for-next

2023-12-27T14:41:04+00:00

Linux 6.7-rc7

gpiolib: cdev: add gpio_device locking wrapper around gpio_ioctl()

2023-12-21T09:27:07+00:00

While the GPIO cdev gpio_ioctl() call is in progress, the kernel can
call gpiochip_remove() which will set gdev->chip to NULL, after which
any subsequent access will cause a crash.

gpio_ioctl() was overlooked by the previous fix to protect syscalls
(bdbbae241a04), so add protection for that.

Fixes: bdbbae241a04 ("gpiolib: protect the GPIO device against being dropped while in use by user-space")
Fixes: d7c51b47ac11 ("gpio: userspace ABI for reading/writing GPIO lines")
Fixes: 3c0d9c635ae2 ("gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL")
Fixes: aad955842d1c ("gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL")
Signed-off-by: Kent Gibson 
Signed-off-by: Bartosz Golaszewski

gpiolib: cdev: reduce locking in gpio_desc_to_lineinfo()

2023-12-19T09:32:52+00:00

Reduce the time holding the gpio_lock by snapshotting the desc flags,
rather than testing them individually while holding the lock.

Accept that the calculation of the used field is inherently racy, and
only check the availability of the line from pinctrl if other checks
pass, so avoiding the check for lines that are otherwise in use.

Signed-off-by: Kent Gibson 
Reviewed-by: Andy Shevchenko 
Signed-off-by: Bartosz Golaszewski

gpiolib: cdev: improve documentation of get/set values

2023-12-19T09:18:49+00:00

Add documentation of the algorithm used to perform scatter/gather
of the requested lines and values in linereq_get_values() and
linereq_set_values_unlocked() to improve maintainability.

Signed-off-by: Kent Gibson 
Reviewed-by: Andy Shevchenko 
Signed-off-by: Bartosz Golaszewski

gpiolib: cdev: fully adopt guard() and scoped_guard()

2023-12-19T09:18:42+00:00

Use guard() or scoped_guard() for critical sections rather than
discrete lock/unlock pairs.

Signed-off-by: Kent Gibson 
Reviewed-by: Andy Shevchenko 
Signed-off-by: Bartosz Golaszewski

gpiolib: cdev: relocate debounce_period_us from struct gpio_desc

2023-12-19T08:45:35+00:00

Store the debounce period for a requested line locally, rather than in
the debounce_period_us field in the gpiolib struct gpio_desc.

Add a global tree of lines containing supplemental line information
to make the debounce period available to be reported by the
GPIO_V2_GET_LINEINFO_IOCTL and the line change notifier.

Signed-off-by: Kent Gibson 
Reviewed-by: Andy Shevchenko 
Signed-off-by: Bartosz Golaszewski