diff options
| author | Bartosz Golaszewski <bartosz.golaszewski@linaro.org> | 2023-08-17 15:18:58 +0200 |
|---|---|---|
| committer | Bartosz Golaszewski <bartosz.golaszewski@linaro.org> | 2023-08-21 15:57:05 +0200 |
| commit | a0dda508bd66b9eeeedc6fe0597aa8613f4b3c5d (patch) | |
| tree | 97e1cdb3c5cb467a4ffbd58a395d7044cd57aa25 /drivers/gpio | |
| parent | d2e2586a3292e05d4872e9111e8b005bc4ff4d09 (diff) | |
gpio: cdev: wake up linereq poll() on device unbind
Add a notifier block to the linereq 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 | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index bc1542544e49..7d0c83127ccb 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -555,6 +555,7 @@ struct line { * @label: consumer label used to tag GPIO descriptors * @num_lines: the number of lines in the lines array * @wait: wait queue that handles blocking reads of events + * @device_unregistered_nb: notifier block for receiving gdev unregister events * @event_buffer_size: the number of elements allocated in @events * @events: KFIFO for the GPIO events * @seqno: the sequence number for edge events generated on all lines in @@ -569,6 +570,7 @@ struct linereq { const char *label; u32 num_lines; wait_queue_head_t wait; + struct notifier_block device_unregistered_nb; u32 event_buffer_size; DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event); atomic_t seqno; @@ -610,6 +612,17 @@ struct linereq { GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \ GPIO_V2_LINE_EDGE_FLAGS) +static int linereq_unregistered_notify(struct notifier_block *nb, + unsigned long action, void *data) +{ + struct linereq *lr = container_of(nb, struct linereq, + device_unregistered_nb); + + wake_up_poll(&lr->wait, EPOLLIN | EPOLLERR); + + return NOTIFY_OK; +} + static void linereq_put_event(struct linereq *lr, struct gpio_v2_line_event *le) { @@ -1567,6 +1580,10 @@ static void linereq_free(struct linereq *lr) { unsigned int i; + if (lr->device_unregistered_nb.notifier_call) + blocking_notifier_chain_unregister(&lr->gdev->device_notifier, + &lr->device_unregistered_nb); + for (i = 0; i < lr->num_lines; i++) { if (lr->lines[i].desc) { edge_detector_stop(&lr->lines[i]); @@ -1727,6 +1744,12 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip) offset); } + lr->device_unregistered_nb.notifier_call = linereq_unregistered_notify; + ret = blocking_notifier_chain_register(&gdev->device_notifier, + &lr->device_unregistered_nb); + if (ret) + goto out_free_linereq; + fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); if (fd < 0) { ret = fd; |