[PATCH v3 1/4] gpiolib: Never return internal error codes to user space

From: Andy Shevchenko
Date: Tue Feb 01 2022 - 10:28:14 EST


Currently it's possible that character device interface may return
the error codes which are not supposed to be seen by user space.
In this case it's EPROBE_DEFER.

Wrap it to return -ENODEV instead as sysfs does.

Fixes: d7c51b47ac11 ("gpio: userspace ABI for reading/writing GPIO lines")
Fixes: 61f922db7221 ("gpio: userspace ABI for reading GPIO line events")
Fixes: 3c0d9c635ae2 ("gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL")
Reported-by: Suresh Balakrishnan <suresh.balakrishnan@xxxxxxxxx>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
drivers/gpio/gpiolib-cdev.c | 6 +++---
drivers/gpio/gpiolib-sysfs.c | 7 ++-----
drivers/gpio/gpiolib.h | 12 ++++++++++++
3 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index c7b5446d01fd..ffa0256cad5a 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -330,7 +330,7 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
goto out_free_lh;
}

- ret = gpiod_request(desc, lh->label);
+ ret = gpiod_request_user(desc, lh->label);
if (ret)
goto out_free_lh;
lh->descs[i] = desc;
@@ -1378,7 +1378,7 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip)
goto out_free_linereq;
}

- ret = gpiod_request(desc, lr->label);
+ ret = gpiod_request_user(desc, lr->label);
if (ret)
goto out_free_linereq;

@@ -1764,7 +1764,7 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip)
}
}

- ret = gpiod_request(desc, le->label);
+ ret = gpiod_request_user(desc, le->label);
if (ret)
goto out_free_le;
le->desc = desc;
diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index 4098bc7f88b7..44c1ad51b3fe 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -475,12 +475,9 @@ static ssize_t export_store(struct class *class,
* they may be undone on its behalf too.
*/

- status = gpiod_request(desc, "sysfs");
- if (status) {
- if (status == -EPROBE_DEFER)
- status = -ENODEV;
+ status = gpiod_request_user(desc, "sysfs");
+ if (status)
goto done;
- }

status = gpiod_set_transitory(desc, false);
if (!status) {
diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h
index 30bc3f80f83e..c31f4626915d 100644
--- a/drivers/gpio/gpiolib.h
+++ b/drivers/gpio/gpiolib.h
@@ -135,6 +135,18 @@ struct gpio_desc {

int gpiod_request(struct gpio_desc *desc, const char *label);
void gpiod_free(struct gpio_desc *desc);
+
+static inline int gpiod_request_user(struct gpio_desc *desc, const char *label)
+{
+ int ret;
+
+ ret = gpiod_request(desc, label);
+ if (ret == -EPROBE_DEFER)
+ ret = -ENODEV;
+
+ return ret;
+}
+
int gpiod_configure_flags(struct gpio_desc *desc, const char *con_id,
unsigned long lflags, enum gpiod_flags dflags);
int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce);
--
2.34.1