Commit ba0bc70d authored Nov 29, 2023 by Boerge Struempfel Committed by Greg Kroah-Hartman Dec 13, 2023

gpiolib: sysfs: Fix error handling on failed export



[ Upstream commit 95dd1e34ff5bbee93a28ff3947eceaf6de811b1a ]

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: e10f72bf ("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>

parent f5d6ab01

drivers/gpio/gpiolib-sysfs.c

+9 −6

Original line number	Diff line number	Diff line
		@@ -495,13 +495,16 @@ static ssize_t export_store(struct class *class,
		}

		status = gpiod_set_transitory(desc, false);
		if (!status) {
		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)