1 files changed, 14 insertions, 20 deletions

diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
index 33617c365acc..9aa530a8bea9 100644
--- a/drivers/media/v4l2-core/v4l2-dev.c
+++ b/drivers/media/v4l2-core/v4l2-dev.c
@@ -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);
+        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;