On 10/04/13 12:07, Lars-Peter Clausen wrote:
> Once the device has been unregistered there won't be any new data no matter how
> long a userspace application waits, so we might as well wake them up and let
> them know.
>
> Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
I guess this makes sense given they'll then do a read and get an error to indicate
that the device is no longer there.
Applied to the togreg branch of iio.git
Thanks,
Jonathan
> ---
> No changes since v1
> ---
> drivers/iio/iio_core.h | 3 +++
> drivers/iio/industrialio-buffer.c | 16 ++++++++++++++++
> drivers/iio/industrialio-core.c | 4 ++++
> drivers/iio/industrialio-event.c | 21 ++++++++++++++++++++-
> 4 files changed, 43 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iio/iio_core.h b/drivers/iio/iio_core.h
> index 9209f47..7512cf7 100644
> --- a/drivers/iio/iio_core.h
> +++ b/drivers/iio/iio_core.h
> @@ -50,6 +50,7 @@ ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
> #define iio_buffer_read_first_n_outer_addr (&iio_buffer_read_first_n_outer)
>
> void iio_disable_all_buffers(struct iio_dev *indio_dev);
> +void iio_buffer_wakeup_poll(struct iio_dev *indio_dev);
>
> #else
>
> @@ -57,11 +58,13 @@ void iio_disable_all_buffers(struct iio_dev *indio_dev);
> #define iio_buffer_read_first_n_outer_addr NULL
>
> static inline void iio_disable_all_buffers(struct iio_dev *indio_dev) {}
> +static inline void iio_buffer_wakeup_poll(struct iio_dev *indio_dev) {}
>
> #endif
>
> int iio_device_register_eventset(struct iio_dev *indio_dev);
> void iio_device_unregister_eventset(struct iio_dev *indio_dev);
> +void iio_device_wakeup_eventset(struct iio_dev *indio_dev);
> int iio_event_getfd(struct iio_dev *indio_dev);
>
> #endif
> diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
> index 6c7a9c5..5a46c57 100644
> --- a/drivers/iio/industrialio-buffer.c
> +++ b/drivers/iio/industrialio-buffer.c
> @@ -20,6 +20,7 @@
> #include <linux/cdev.h>
> #include <linux/slab.h>
> #include <linux/poll.h>
> +#include <linux/sched.h>
>
> #include <linux/iio/iio.h>
> #include "iio_core.h"
> @@ -75,6 +76,21 @@ unsigned int iio_buffer_poll(struct file *filp,
> return 0;
> }
>
> +/**
> + * iio_buffer_wakeup_poll - Wakes up the buffer waitqueue
> + * @indio_dev: The IIO device
> + *
> + * Wakes up the event waitqueue used for poll(). Should usually
> + * be called when the device is unregistered.
> + */
> +void iio_buffer_wakeup_poll(struct iio_dev *indio_dev)
> +{
> + if (!indio_dev->buffer)
> + return;
> +
> + wake_up(&indio_dev->buffer->pollq);
> +}
> +
> void iio_buffer_init(struct iio_buffer *buffer)
> {
> INIT_LIST_HEAD(&buffer->demux_list);
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index c9c6558..81650e1 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -1139,6 +1139,10 @@ void iio_device_unregister(struct iio_dev *indio_dev)
> iio_disable_all_buffers(indio_dev);
>
> indio_dev->info = NULL;
> +
> + iio_device_wakeup_eventset(indio_dev);
> + iio_buffer_wakeup_poll(indio_dev);
> +
> mutex_unlock(&indio_dev->info_exist_lock);
> }
> EXPORT_SYMBOL(iio_device_unregister);
> diff --git a/drivers/iio/industrialio-event.c b/drivers/iio/industrialio-event.c
> index 837d450..d251f30 100644
> --- a/drivers/iio/industrialio-event.c
> +++ b/drivers/iio/industrialio-event.c
> @@ -113,9 +113,14 @@ static ssize_t iio_event_chrdev_read(struct file *filep,
> }
> /* Blocking on device; waiting for something to be there */
> ret = wait_event_interruptible_locked_irq(ev_int->wait,
> - !kfifo_is_empty(&ev_int->det_events));
> + !kfifo_is_empty(&ev_int->det_events) ||
> + indio_dev->info == NULL);
> if (ret)
> goto error_unlock;
> + if (indio_dev->info == NULL) {
> + ret = -ENODEV;
> + goto error_unlock;
> + }
> /* Single access device so no one else can get the data */
> }
>
> @@ -454,6 +459,20 @@ error_ret:
> return ret;
> }
>
> +/**
> + * iio_device_wakeup_eventset - Wakes up the event waitqueue
> + * @indio_dev: The IIO device
> + *
> + * Wakes up the event waitqueue used for poll() and blocking read().
> + * Should usually be called when the device is unregistered.
> + */
> +void iio_device_wakeup_eventset(struct iio_dev *indio_dev)
> +{
> + if (indio_dev->event_interface == NULL)
> + return;
> + wake_up(&indio_dev->event_interface->wait);
> +}
> +
> void iio_device_unregister_eventset(struct iio_dev *indio_dev)
> {
> if (indio_dev->event_interface == NULL)
>
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