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iio: Wakeup poll and blocking reads when the device is unregistered

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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@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Lars-Peter Clausen 2013-10-04 12:07:00 +01:00 committed by Jonathan Cameron
parent f18e7a068a
commit d2f0a48f36
4 changed files with 43 additions and 1 deletions
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3
drivers/iio/iio_core.h
View File

@ -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

16
drivers/iio/industrialio-buffer.c
View File

@ -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);

4
drivers/iio/industrialio-core.c
View File

@ -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);

21
drivers/iio/industrialio-event.c
View File

@ -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)