diff options
| author | Bartosz Golaszewski <bartosz.golaszewski@linaro.org> | 2023-08-17 15:42:24 +0300 |
|---|---|---|
| committer | Bartosz Golaszewski <bartosz.golaszewski@linaro.org> | 2023-08-21 16:57:05 +0300 |
| commit | d2e2586a3292e05d4872e9111e8b005bc4ff4d09 (patch) | |
| tree | 2a7adc4a981f08c98ef7ac28e17b578114139a3f /drivers/gpio | |
| parent | a067419ba77da830939852758702388f0fba09a1 (diff) | |
| download | linux-d2e2586a3292e05d4872e9111e8b005bc4ff4d09.tar.xz | |
gpio: cdev: wake up chardev poll() on device unbind
Add a notifier block to the gpio_chardev_data structure and register it
with the gpio_device's device notifier. Upon reception of an event, wake
up the wait queue so that the user-space be forced out of poll() and need
to go into a new system call which will then fail due to the chip being
gone.
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Kent Gibson <warthog618@gmail.com>
Diffstat (limited to 'drivers/gpio')
| -rw-r--r-- | drivers/gpio/gpiolib-cdev.c | 29 |
1 files changed, 27 insertions, 2 deletions
diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index fec446510028..bc1542544e49 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -2320,6 +2320,7 @@ struct gpio_chardev_data { wait_queue_head_t wait; DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32); struct notifier_block lineinfo_changed_nb; + struct notifier_block device_unregistered_nb; unsigned long *watched_lines; #ifdef CONFIG_GPIO_CDEV_V1 atomic_t watch_abi_version; @@ -2517,6 +2518,18 @@ static int lineinfo_changed_notify(struct notifier_block *nb, return NOTIFY_OK; } +static int gpio_device_unregistered_notify(struct notifier_block *nb, + unsigned long action, void *data) +{ + struct gpio_chardev_data *cdev = container_of(nb, + struct gpio_chardev_data, + device_unregistered_nb); + + wake_up_poll(&cdev->wait, EPOLLIN | EPOLLERR); + + return NOTIFY_OK; +} + static __poll_t lineinfo_watch_poll_unlocked(struct file *file, struct poll_table_struct *pollt) { @@ -2671,17 +2684,27 @@ static int gpio_chrdev_open(struct inode *inode, struct file *file) if (ret) goto out_free_bitmap; + cdev->device_unregistered_nb.notifier_call = + gpio_device_unregistered_notify; + ret = blocking_notifier_chain_register(&gdev->device_notifier, + &cdev->device_unregistered_nb); + if (ret) + goto out_unregister_line_notifier; + file->private_data = cdev; ret = nonseekable_open(inode, file); if (ret) - goto out_unregister_notifier; + goto out_unregister_device_notifier; up_read(&gdev->sem); return ret; -out_unregister_notifier: +out_unregister_device_notifier: + blocking_notifier_chain_unregister(&gdev->device_notifier, + &cdev->device_unregistered_nb); +out_unregister_line_notifier: blocking_notifier_chain_unregister(&gdev->line_state_notifier, &cdev->lineinfo_changed_nb); out_free_bitmap: @@ -2706,6 +2729,8 @@ static int gpio_chrdev_release(struct inode *inode, struct file *file) struct gpio_device *gdev = cdev->gdev; bitmap_free(cdev->watched_lines); + blocking_notifier_chain_unregister(&gdev->device_notifier, + &cdev->device_unregistered_nb); blocking_notifier_chain_unregister(&gdev->line_state_notifier, &cdev->lineinfo_changed_nb); gpio_device_put(gdev); |