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Commit d2f0a48f authored by Lars-Peter Clausen's avatar Lars-Peter Clausen Committed by Jonathan Cameron
Browse files

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



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: default avatarLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent f18e7a06

drivers/iio/iio_core.h

+3 −0
Original line number Diff line number Diff line
@@ -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

drivers/iio/industrialio-buffer.c

+16 −0
Original line number Diff line number Diff line
@@ -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);

drivers/iio/industrialio-core.c

+4 −0
Original line number Diff line number Diff line
@@ -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);

drivers/iio/industrialio-event.c

+20 −1
Original line number Diff line number Diff line
@@ -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 @@ int iio_device_register_eventset(struct iio_dev *indio_dev) 
	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)