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gpiolib: sysfs: Fix error handling on failed export 

[ Upstream commit 95dd1e34ff ]

If gpio_set_transitory() fails, we should free the GPIO again. Most
notably, the flag FLAG_REQUESTED has previously been set in
gpiod_request_commit(), and should be reset on failure.

To my knowledge, this does not affect any current users, since the
gpio_set_transitory() mainly returns 0 and -ENOTSUPP, which is converted
to 0. However the gpio_set_transitory() function calles the .set_config()
function of the corresponding GPIO chip and there are some GPIO drivers in
which some (unlikely) branches return other values like -EPROBE_DEFER,
and -EINVAL. In these cases, the above mentioned FLAG_REQUESTED would not
be reset, which results in the pin being blocked until the next reboot.

Fixes: e10f72bf4b ("gpio: gpiolib: Generalise state persistence beyond sleep")
Signed-off-by: Boerge Struempfel <boerge.struempfel@gmail.com>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Boerge Struempfel 2023-11-29 16:23:07 +01:00 committed by Greg Kroah-Hartman
parent 208dd116f9
commit b5862e5ca5
1 changed files with 9 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
drivers/gpio/gpiolib-sysfs.c
View File

@ -491,14 +491,17 @@ static ssize_t export_store(struct class *class,
}
status = gpiod_set_transitory(desc, false);
if (!status) {
status = gpiod_export(desc, true);
if (status < 0)
gpiod_free(desc);
else
set_bit(FLAG_SYSFS, &desc->flags);
if (status) {
gpiod_free(desc);
goto done;
}
status = gpiod_export(desc, true);
if (status < 0)
gpiod_free(desc);
else
set_bit(FLAG_SYSFS, &desc->flags);
done:
if (status)
pr_debug("%s: status %d\n", __func__, status);