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Commit 43ba1100 authored by Lars-Peter Clausen's avatar Lars-Peter Clausen Committed by Greg Kroah-Hartman
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staging:iio:events: Use waitqueue lock to protect event queue 



Use the waitqueue lock to protect the event queue instead of a custom mutex.
This has the advantage that we can call the waitqueue operations with the lock
held, which simplifies the code flow a bit.

Signed-off-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Acked-by: default avatarJonathan Cameron <jic23@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 2c00193f

drivers/staging/iio/industrialio-event.c

+18 −25
Original line number Diff line number Diff line
@@ -35,7 +35,6 @@ 
 */

struct iio_event_interface {

	wait_queue_head_t	wait;

	struct mutex		event_list_lock;

	DECLARE_KFIFO(det_events, struct iio_event_data, 16);



	struct list_head	dev_attr_list;
@@ -50,19 +49,17 @@ int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp) 
	int copied;



	/* Does anyone care? */

	mutex_lock(&ev_int->event_list_lock);

	spin_lock(&ev_int->wait.lock);

	if (test_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {



		ev.id = ev_code;

		ev.timestamp = timestamp;



		copied = kfifo_put(&ev_int->det_events, &ev);



		mutex_unlock(&ev_int->event_list_lock);

		if (copied != 0)

			wake_up_interruptible(&ev_int->wait);

	} else

		mutex_unlock(&ev_int->event_list_lock);

			wake_up_locked(&ev_int->wait);

	}

	spin_unlock(&ev_int->wait.lock);



	return 0;

}
@@ -80,28 +77,25 @@ static ssize_t iio_event_chrdev_read(struct file *filep, 
	if (count < sizeof(struct iio_event_data))

		return -EINVAL;



	mutex_lock(&ev_int->event_list_lock);

	spin_lock(&ev_int->wait.lock);

	if (kfifo_is_empty(&ev_int->det_events)) {

		if (filep->f_flags & O_NONBLOCK) {

			ret = -EAGAIN;

			goto error_mutex_unlock;

			goto error_unlock;

		}

		mutex_unlock(&ev_int->event_list_lock);

		/* Blocking on device; waiting for something to be there */

		ret = wait_event_interruptible(ev_int->wait,

		ret = wait_event_interruptible_locked(ev_int->wait,

					!kfifo_is_empty(&ev_int->det_events));

		if (ret)

			goto error_ret;

			goto error_unlock;

		/* Single access device so no one else can get the data */

		mutex_lock(&ev_int->event_list_lock);

	}



	mutex_unlock(&ev_int->event_list_lock);

	ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied);



error_mutex_unlock:

	mutex_unlock(&ev_int->event_list_lock);

error_ret:

error_unlock:

	spin_unlock(&ev_int->wait.lock);



	return ret ? ret : copied;

}
@@ -109,7 +103,7 @@ static int iio_event_chrdev_release(struct inode *inode, struct file *filep) 
{

	struct iio_event_interface *ev_int = filep->private_data;



	mutex_lock(&ev_int->event_list_lock);

	spin_lock(&ev_int->wait.lock);

	clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);

	/*

	 * In order to maintain a clean state for reopening,
@@ -117,7 +111,7 @@ static int iio_event_chrdev_release(struct inode *inode, struct file *filep) 
	 * any new __iio_push_event calls running.

	 */

	kfifo_reset_out(&ev_int->det_events);

	mutex_unlock(&ev_int->event_list_lock);

	spin_unlock(&ev_int->wait.lock);



	return 0;

}
@@ -137,18 +131,18 @@ int iio_event_getfd(struct iio_dev *indio_dev) 
	if (ev_int == NULL)

		return -ENODEV;



	mutex_lock(&ev_int->event_list_lock);

	spin_lock(&ev_int->wait.lock);

	if (test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {

		mutex_unlock(&ev_int->event_list_lock);

		spin_unlock(&ev_int->wait.lock);

		return -EBUSY;

	}

	mutex_unlock(&ev_int->event_list_lock);

	spin_unlock(&ev_int->wait.lock);

	fd = anon_inode_getfd("iio:event",

				&iio_event_chrdev_fileops, ev_int, O_RDONLY);

	if (fd < 0) {

		mutex_lock(&ev_int->event_list_lock);

		spin_lock(&ev_int->wait.lock);

		clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);

		mutex_unlock(&ev_int->event_list_lock);

		spin_unlock(&ev_int->wait.lock);

	}

	return fd;

}
@@ -360,7 +354,6 @@ static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev) 


static void iio_setup_ev_int(struct iio_event_interface *ev_int)

{

	mutex_init(&ev_int->event_list_lock);

	INIT_KFIFO(ev_int->det_events);

	init_waitqueue_head(&ev_int->wait);

}