| Message ID | 20240610100530.1107771-16-sakari.ailus@linux.intel.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Media device lifetime management | expand |
On 10/06/2024 12:05, Sakari Ailus wrote: > The video device depends on the existence of its media device --- if there > is one. Acquire a reference to it. > > Note that when the media device release callback is used, then the V4L2 > device release callback is ignored and a warning is issued if both are > set. > > Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Regards, Hans > --- > drivers/media/v4l2-core/v4l2-dev.c | 53 ++++++++++++++++++++---------- > 1 file changed, 35 insertions(+), 18 deletions(-) > > diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c > index be2ba7ca5de2..4bf4398fd2fe 100644 > --- a/drivers/media/v4l2-core/v4l2-dev.c > +++ b/drivers/media/v4l2-core/v4l2-dev.c > @@ -176,6 +176,11 @@ static void v4l2_device_release(struct device *cd) > { > struct video_device *vdev = to_video_device(cd); > struct v4l2_device *v4l2_dev = vdev->v4l2_dev; > + bool v4l2_dev_call_release = v4l2_dev->release; > +#ifdef CONFIG_MEDIA_CONTROLLER > + struct media_device *mdev = v4l2_dev->mdev; > + bool mdev_has_release = mdev && mdev->ops && mdev->ops->release; > +#endif > > mutex_lock(&videodev_lock); > if (WARN_ON(video_devices[vdev->minor] != vdev)) { > @@ -198,8 +203,8 @@ static void v4l2_device_release(struct device *cd) > > mutex_unlock(&videodev_lock); > > -#if defined(CONFIG_MEDIA_CONTROLLER) > - if (v4l2_dev->mdev && vdev->vfl_dir != VFL_DIR_M2M) { > +#ifdef CONFIG_MEDIA_CONTROLLER > + if (mdev && vdev->vfl_dir != VFL_DIR_M2M) { > /* Remove interfaces and interface links */ > media_devnode_remove(vdev->intf_devnode); > if (vdev->entity.function != MEDIA_ENT_F_UNKNOWN) > @@ -207,23 +212,28 @@ static void v4l2_device_release(struct device *cd) > } > #endif > > - /* Do not call v4l2_device_put if there is no release callback set. > - * Drivers that have no v4l2_device release callback might free the > - * v4l2_dev instance in the video_device release callback below, so we > - * must perform this check here. > - * > - * 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->release == NULL) > - v4l2_dev = NULL; > - > /* Release video_device and perform other > cleanups as needed. */ > vdev->release(vdev); > > - /* Decrease v4l2_device refcount */ > - if (v4l2_dev) > +#ifdef CONFIG_MEDIA_CONTROLLER > + if (mdev) > + media_device_put(mdev); > + > + /* > + * Generally both struct media_device and struct v4l2_device are > + * embedded in the same driver's context struct so having a release > + * callback in both is a bug. > + */ > + if (WARN_ON(v4l2_dev_call_release && mdev_has_release)) > + v4l2_dev_call_release = false; > +#endif > + > + /* > + * Decrease v4l2_device refcount, but only if the media device doesn't > + * have a release callback. > + */ > + if (v4l2_dev_call_release) > v4l2_device_put(v4l2_dev); > } > > @@ -795,11 +805,17 @@ static int video_register_media_controller(struct video_device *vdev) > u32 intf_type; > int ret; > > - /* Memory-to-memory devices are more complex and use > - * their own function to register its mc entities. > + if (!vdev->v4l2_dev->mdev) > + return 0; > + > + /* > + * Memory-to-memory devices are more complex and use their own function > + * to register its mc entities. > */ > - if (!vdev->v4l2_dev->mdev || vdev->vfl_dir == VFL_DIR_M2M) > + if (vdev->vfl_dir == VFL_DIR_M2M) { > + media_device_get(vdev->v4l2_dev->mdev); > return 0; > + } > > vdev->entity.obj_type = MEDIA_ENTITY_TYPE_VIDEO_DEVICE; > vdev->entity.function = MEDIA_ENT_F_UNKNOWN; > @@ -878,6 +894,7 @@ static int video_register_media_controller(struct video_device *vdev) > > /* FIXME: how to create the other interface links? */ > > + media_device_get(vdev->v4l2_dev->mdev); > #endif > return 0; > }
diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c index be2ba7ca5de2..4bf4398fd2fe 100644 --- a/drivers/media/v4l2-core/v4l2-dev.c +++ b/drivers/media/v4l2-core/v4l2-dev.c @@ -176,6 +176,11 @@ static void v4l2_device_release(struct device *cd) { struct video_device *vdev = to_video_device(cd); struct v4l2_device *v4l2_dev = vdev->v4l2_dev; + bool v4l2_dev_call_release = v4l2_dev->release; +#ifdef CONFIG_MEDIA_CONTROLLER + struct media_device *mdev = v4l2_dev->mdev; + bool mdev_has_release = mdev && mdev->ops && mdev->ops->release; +#endif mutex_lock(&videodev_lock); if (WARN_ON(video_devices[vdev->minor] != vdev)) { @@ -198,8 +203,8 @@ static void v4l2_device_release(struct device *cd) mutex_unlock(&videodev_lock); -#if defined(CONFIG_MEDIA_CONTROLLER) - if (v4l2_dev->mdev && vdev->vfl_dir != VFL_DIR_M2M) { +#ifdef CONFIG_MEDIA_CONTROLLER + if (mdev && vdev->vfl_dir != VFL_DIR_M2M) { /* Remove interfaces and interface links */ media_devnode_remove(vdev->intf_devnode); if (vdev->entity.function != MEDIA_ENT_F_UNKNOWN) @@ -207,23 +212,28 @@ static void v4l2_device_release(struct device *cd) } #endif - /* Do not call v4l2_device_put if there is no release callback set. - * Drivers that have no v4l2_device release callback might free the - * v4l2_dev instance in the video_device release callback below, so we - * must perform this check here. - * - * 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->release == NULL) - v4l2_dev = NULL; - /* Release video_device and perform other cleanups as needed. */ vdev->release(vdev); - /* Decrease v4l2_device refcount */ - if (v4l2_dev) +#ifdef CONFIG_MEDIA_CONTROLLER + if (mdev) + media_device_put(mdev); + + /* + * Generally both struct media_device and struct v4l2_device are + * embedded in the same driver's context struct so having a release + * callback in both is a bug. + */ + if (WARN_ON(v4l2_dev_call_release && mdev_has_release)) + v4l2_dev_call_release = false; +#endif + + /* + * Decrease v4l2_device refcount, but only if the media device doesn't + * have a release callback. + */ + if (v4l2_dev_call_release) v4l2_device_put(v4l2_dev); } @@ -795,11 +805,17 @@ static int video_register_media_controller(struct video_device *vdev) u32 intf_type; int ret; - /* Memory-to-memory devices are more complex and use - * their own function to register its mc entities. + if (!vdev->v4l2_dev->mdev) + return 0; + + /* + * Memory-to-memory devices are more complex and use their own function + * to register its mc entities. */ - if (!vdev->v4l2_dev->mdev || vdev->vfl_dir == VFL_DIR_M2M) + if (vdev->vfl_dir == VFL_DIR_M2M) { + media_device_get(vdev->v4l2_dev->mdev); return 0; + } vdev->entity.obj_type = MEDIA_ENTITY_TYPE_VIDEO_DEVICE; vdev->entity.function = MEDIA_ENT_F_UNKNOWN; @@ -878,6 +894,7 @@ static int video_register_media_controller(struct video_device *vdev) /* FIXME: how to create the other interface links? */ + media_device_get(vdev->v4l2_dev->mdev); #endif return 0; }
The video device depends on the existence of its media device --- if there is one. Acquire a reference to it. Note that when the media device release callback is used, then the V4L2 device release callback is ignored and a warning is issued if both are set. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> --- drivers/media/v4l2-core/v4l2-dev.c | 53 ++++++++++++++++++++---------- 1 file changed, 35 insertions(+), 18 deletions(-)