4.19-stable review patch. If anyone has any objections, please let me know.
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From: Boerge Struempfel boerge.struempfel@gmail.com
[ 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: 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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpio/gpiolib-sysfs.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c index e0ccc79b239a5..7a8dfc36a6c15 100644 --- a/drivers/gpio/gpiolib-sysfs.c +++ b/drivers/gpio/gpiolib-sysfs.c @@ -495,14 +495,17 @@ 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);