gpiolib: sysfs: Fix error handling on failed export

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: e10f72bf4b3e ("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>

diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index 6f309a3b2d9ade8a30e14e76a3b861c573302705..12d853845bb803bb8b5d35aa72a11e9adb8bb85d 100644 (file)
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -474,14 +474,17 @@ static ssize_t export_store(const struct class *class,
                goto done;
 
        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);