Messages in this thread Patch in this message | | | From | Boerge Struempfel <> | Subject | [PATCH v2] gpiolib: sysfs: Fix error handling on failed export | Date | Tue, 28 Nov 2023 15:13:21 +0100 |
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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.
Signed-off-by: Boerge Struempfel <boerge.struempfel@gmail.com>
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V1: https://lore.kernel.org/linux-gpio/CAEktqcuxS1sPfkGVCgSy1ki8fmUDmuUsHrdAT+zFKy5vGSoKPw@mail.gmail.com/T/#t
Changes from V1: - Marked all functions in commit message with parenthesis - Elaborated in commit message
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 6f309a3b2d9a..12d853845bb8 100644 --- 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); -- 2.42.0
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