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Commit d9bfbcc0 authored by Hans Verkuil's avatar Hans Verkuil Committed by Mauro Carvalho Chehab
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[media] v4l2-dev: vdev->v4l2_dev is always set, so simplify code 



These days vdev->v4l2_dev must always be set. This means that some
old code that still tests for a NULL vdev->v4l2_dev can be removed
or simplified.

Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@osg.samsung.com>
parent 872dfcfe

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

+14 −20
Original line number Diff line number Diff line
@@ -194,7 +194,7 @@ static void v4l2_device_release(struct device *cd) 
	mutex_unlock(&videodev_lock);



#if defined(CONFIG_MEDIA_CONTROLLER)

	if (v4l2_dev && v4l2_dev->mdev &&

	if (v4l2_dev->mdev &&

	    vdev->vfl_type != VFL_TYPE_SUBDEV)

		media_device_unregister_entity(&vdev->entity);

#endif
@@ -207,7 +207,7 @@ static void v4l2_device_release(struct device *cd) 
	 * TODO: In the long run all drivers that use v4l2_device should use the

	 * v4l2_device release callback. This check will then be unnecessary.

	 */

	if (v4l2_dev && v4l2_dev->release == NULL)

	if (v4l2_dev->release == NULL)

		v4l2_dev = NULL;



	/* Release video_device and perform other
@@ -360,27 +360,22 @@ static long v4l2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 
		 * hack but it will have to do for those drivers that are not

		 * yet converted to use unlocked_ioctl.

		 *

		 * There are two options: if the driver implements struct

		 * v4l2_device, then the lock defined there is used to

		 * serialize the ioctls. Otherwise the v4l2 core lock defined

		 * below is used. This lock is really bad since it serializes

		 * completely independent devices.

		 * All drivers implement struct v4l2_device, so we use the

		 * lock defined there to serialize the ioctls.

		 *

		 * Both variants suffer from the same problem: if the driver

		 * sleeps, then it blocks all ioctls since the lock is still

		 * held. This is very common for VIDIOC_DQBUF since that

		 * normally waits for a frame to arrive. As a result any other

		 * ioctl calls will proceed very, very slowly since each call

		 * will have to wait for the VIDIOC_QBUF to finish. Things that

		 * should take 0.01s may now take 10-20 seconds.

		 * However, if the driver sleeps, then it blocks all ioctls

		 * since the lock is still held. This is very common for

		 * VIDIOC_DQBUF since that normally waits for a frame to arrive.

		 * As a result any other ioctl calls will proceed very, very

		 * slowly since each call will have to wait for the VIDIOC_QBUF

		 * to finish. Things that should take 0.01s may now take 10-20

		 * seconds.

		 *

		 * The workaround is to *not* take the lock for VIDIOC_DQBUF.

		 * This actually works OK for videobuf-based drivers, since

		 * videobuf will take its own internal lock.

		 */

		static DEFINE_MUTEX(v4l2_ioctl_mutex);

		struct mutex *m = vdev->v4l2_dev ?

			&vdev->v4l2_dev->ioctl_lock : &v4l2_ioctl_mutex;

		struct mutex *m = &vdev->v4l2_dev->ioctl_lock;



		if (cmd != VIDIOC_DQBUF && mutex_lock_interruptible(m))

			return -ERESTARTSYS;
@@ -938,12 +933,11 @@ int __video_register_device(struct video_device *vdev, int type, int nr, 
			name_base, nr, video_device_node_name(vdev));



	/* Increase v4l2_device refcount */

	if (vdev->v4l2_dev)

	v4l2_device_get(vdev->v4l2_dev);



#if defined(CONFIG_MEDIA_CONTROLLER)

	/* Part 5: Register the entity. */

	if (vdev->v4l2_dev && vdev->v4l2_dev->mdev &&

	if (vdev->v4l2_dev->mdev &&

	    vdev->vfl_type != VFL_TYPE_SUBDEV) {

		vdev->entity.type = MEDIA_ENT_T_DEVNODE_V4L;

		vdev->entity.name = vdev->name;