Commit 28955a61 authored by Hans Verkuil's avatar Hans Verkuil Committed by Mauro Carvalho Chehab
Browse files

media: v4l2-dev/event: add v4l2_event_wake_all() 



When unregistering a V4L2 device node, make sure any filehandles
that are waiting for an event are woken up.

Add v4l2_event_wake_all() to v4l2-event.c and call it from
video_unregister_device().

Otherwise userspace might never know that a device node was removed.

[hverkuil: checkpatch: replaced 'if (vdev == NULL)' by 'if (!vdev)']

Signed-off-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
parent 726daf6b

drivers/media/v4l2-core/v4l2-dev.c

+3 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#include <media/v4l2-common.h>

#include <media/v4l2-device.h>

#include <media/v4l2-ioctl.h>

#include <media/v4l2-event.h>



#define VIDEO_NUM_DEVICES	256

#define VIDEO_NAME              "video4linux"
@@ -1086,6 +1087,8 @@ void video_unregister_device(struct video_device *vdev) 
	 */

	clear_bit(V4L2_FL_REGISTERED, &vdev->flags);

	mutex_unlock(&videodev_lock);

	if (test_bit(V4L2_FL_USES_V4L2_FH, &vdev->flags))

		v4l2_event_wake_all(vdev);

	device_unregister(&vdev->dev);

}

EXPORT_SYMBOL(video_unregister_device);

drivers/media/v4l2-core/v4l2-event.c

+17 −0
Original line number Diff line number Diff line
@@ -187,6 +187,23 @@ int v4l2_event_pending(struct v4l2_fh *fh) 
}

EXPORT_SYMBOL_GPL(v4l2_event_pending);



void v4l2_event_wake_all(struct video_device *vdev)

{

	struct v4l2_fh *fh;

	unsigned long flags;



	if (!vdev)

		return;



	spin_lock_irqsave(&vdev->fh_lock, flags);



	list_for_each_entry(fh, &vdev->fh_list, list)

		wake_up_all(&fh->wait);



	spin_unlock_irqrestore(&vdev->fh_lock, flags);

}

EXPORT_SYMBOL_GPL(v4l2_event_wake_all);



static void __v4l2_event_unsubscribe(struct v4l2_subscribed_event *sev)

{

	struct v4l2_fh *fh = sev->fh;

include/media/v4l2-event.h

+11 −2
Original line number Diff line number Diff line
@@ -120,6 +120,15 @@ void v4l2_event_queue(struct video_device *vdev, const struct v4l2_event *ev); 
 */

void v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *ev);



/**

 * v4l2_event_wake_all - Wake all filehandles.

 *

 * Used when unregistering a video device.

 *

 * @vdev: pointer to &struct video_device

 */

void v4l2_event_wake_all(struct video_device *vdev);



/**

 * v4l2_event_pending - Check if an event is available

 *