diff options
| author | Kent Gibson <warthog618@gmail.com> | 2024-05-29 21:19:53 +0800 |
|---|---|---|
| committer | Bartosz Golaszewski <bartosz.golaszewski@linaro.org> | 2024-05-30 11:29:10 +0200 |
| commit | 2ba4746b418dcffadb3b135657fea8d3e62b4c30 (patch) | |
| tree | e919947b90d2b82a0c0efc2d9e76dd6008fd7031 /drivers/gpio/gpiolib-cdev.c | |
| parent | 4ce5ca654a761462a222164e96b8ab953b8cacab (diff) | |
gpiolib: cdev: Cleanup kfifo_out() error handling
The handling of kfifo_out() errors in read functions obscures any error.
The error condition should never occur but, while a ret is set to -EIO, it
is subsequently ignored and the read functions instead return the number
of bytes copied to that point, potentially masking the fact that any error
occurred.
Log a warning and return -EIO in the case of a kfifo_out() error to make
it clear something very odd is going on here.
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20240529131953.195777-4-warthog618@gmail.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Diffstat (limited to 'drivers/gpio/gpiolib-cdev.c')
| -rw-r--r-- | drivers/gpio/gpiolib-cdev.c | 53 |
1 files changed, 27 insertions, 26 deletions
diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index c7218c9f2c5e..1cb952daacfb 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -1642,16 +1642,15 @@ static ssize_t linereq_read(struct file *file, char __user *buf, return ret; } - ret = kfifo_out(&lr->events, &le, 1); - } - if (ret != 1) { - /* - * This should never happen - we were holding the - * lock from the moment we learned the fifo is no - * longer empty until now. - */ - ret = -EIO; - break; + if (kfifo_out(&lr->events, &le, 1) != 1) { + /* + * This should never happen - we hold the + * lock from the moment we learned the fifo + * is no longer empty until now. + */ + WARN(1, "failed to read from non-empty kfifo"); + return -EIO; + } } if (copy_to_user(buf + bytes_read, &le, sizeof(le))) @@ -1995,16 +1994,15 @@ static ssize_t lineevent_read(struct file *file, char __user *buf, return ret; } - ret = kfifo_out(&le->events, &ge, 1); - } - if (ret != 1) { - /* - * This should never happen - we were holding the lock - * from the moment we learned the fifo is no longer - * empty until now. - */ - ret = -EIO; - break; + if (kfifo_out(&le->events, &ge, 1) != 1) { + /* + * This should never happen - we hold the + * lock from the moment we learned the fifo + * is no longer empty until now. + */ + WARN(1, "failed to read from non-empty kfifo"); + return -EIO; + } } if (copy_to_user(buf + bytes_read, &ge, ge_size)) @@ -2707,12 +2705,15 @@ static ssize_t lineinfo_watch_read(struct file *file, char __user *buf, if (count < event_size) return -EINVAL; #endif - ret = kfifo_out(&cdev->events, &event, 1); - } - if (ret != 1) { - ret = -EIO; - break; - /* We should never get here. See lineevent_read(). */ + if (kfifo_out(&cdev->events, &event, 1) != 1) { + /* + * This should never happen - we hold the + * lock from the moment we learned the fifo + * is no longer empty until now. + */ + WARN(1, "failed to read from non-empty kfifo"); + return -EIO; + } } #ifdef CONFIG_GPIO_CDEV_V1 |