diff options
| author | Bartosz Golaszewski <bartosz.golaszewski@linaro.org> | 2023-08-17 15:28:31 +0200 |
|---|---|---|
| committer | Bartosz Golaszewski <bartosz.golaszewski@linaro.org> | 2023-08-21 15:57:05 +0200 |
| commit | 91043f559313fb04ac18253fcf18561a40c1b045 (patch) | |
| tree | 85020b3d8d12772e41e7b6821324e0d5d41b170d | |
| parent | a0dda508bd66b9eeeedc6fe0597aa8613f4b3c5d (diff) | |
gpio: cdev: wake up lineevent poll() on device unbind
Add a notifier block to the lineevent_state 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>
| -rw-r--r-- | drivers/gpio/gpiolib-cdev.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index 7d0c83127ccb..35dcaf78aed6 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -1802,6 +1802,7 @@ out_free_linereq: * @eflags: the event flags this line was requested with * @irq: the interrupt that trigger in response to events on this GPIO * @wait: wait queue that handles blocking reads of events + * @device_unregistered_nb: notifier block for receiving gdev unregister events * @events: KFIFO for the GPIO events * @timestamp: cache for the timestamp storing it between hardirq * and IRQ thread, used to bring the timestamp close to the actual @@ -1814,6 +1815,7 @@ struct lineevent_state { u32 eflags; int irq; wait_queue_head_t wait; + struct notifier_block device_unregistered_nb; DECLARE_KFIFO(events, struct gpioevent_data, 16); u64 timestamp; }; @@ -1847,6 +1849,17 @@ static __poll_t lineevent_poll(struct file *file, return call_poll_locked(file, wait, le->gdev, lineevent_poll_unlocked); } +static int lineevent_unregistered_notify(struct notifier_block *nb, + unsigned long action, void *data) +{ + struct lineevent_state *le = container_of(nb, struct lineevent_state, + device_unregistered_nb); + + wake_up_poll(&le->wait, EPOLLIN | EPOLLERR); + + return NOTIFY_OK; +} + struct compat_gpioeevent_data { compat_u64 timestamp; u32 id; @@ -1932,6 +1945,9 @@ static ssize_t lineevent_read(struct file *file, char __user *buf, static void lineevent_free(struct lineevent_state *le) { + if (le->device_unregistered_nb.notifier_call) + blocking_notifier_chain_unregister(&le->gdev->device_notifier, + &le->device_unregistered_nb); if (le->irq) free_irq(le->irq, le); if (le->desc) @@ -2160,6 +2176,12 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip) INIT_KFIFO(le->events); init_waitqueue_head(&le->wait); + le->device_unregistered_nb.notifier_call = lineevent_unregistered_notify; + ret = blocking_notifier_chain_register(&gdev->device_notifier, + &le->device_unregistered_nb); + if (ret) + goto out_free_le; + /* Request a thread to read the events */ ret = request_threaded_irq(irq, lineevent_irq_handler, |