Hi Guennadi,
On Monday 12 September 2011 12:55:46 Guennadi Liakhovetski wrote:
> Currently only very few drivers actually use video_device nodes, embedded
> in struct v4l2_subdev. Allocate these nodes dynamically for those drivers
> to save memory for the rest.
>
> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
> ---
>
> v3: addressed comments from Laurent Pinchart - thanks
Thanks for the patch. Just one small comment below.
> 1. switch to using a device-release method, instead of freeing directly in
> v4l2_device_unregister_subdev()
>
> 2. switch to using drvdata instead of a wrapper struct
>
> drivers/media/video/v4l2-device.c | 41
> ++++++++++++++++++++++++++++++++---- include/media/v4l2-subdev.h |
> 4 +-
> 2 files changed, 38 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/media/video/v4l2-device.c
> b/drivers/media/video/v4l2-device.c index c72856c..9bf3d70 100644
> --- a/drivers/media/video/v4l2-device.c
> +++ b/drivers/media/video/v4l2-device.c
> @@ -21,6 +21,7 @@
> #include <linux/types.h>
> #include <linux/ioctl.h>
> #include <linux/i2c.h>
> +#include <linux/slab.h>
> #if defined(CONFIG_SPI)
> #include <linux/spi/spi.h>
> #endif
> @@ -191,6 +192,13 @@ int v4l2_device_register_subdev(struct v4l2_device
> *v4l2_dev, }
> EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
>
> +void v4l2_device_release_subdev_node(struct video_device *vdev)
> +{
> + struct v4l2_subdev *sd = video_get_drvdata(vdev);
> + sd->devnode = NULL;
> + kfree(vdev);
> +}
> +
> int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
> {
> struct video_device *vdev;
> @@ -204,22 +212,42 @@ int v4l2_device_register_subdev_nodes(struct
> v4l2_device *v4l2_dev) if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
> continue;
>
> - vdev = &sd->devnode;
> + vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
> + if (!vdev) {
> + err = -ENOMEM;
> + goto clean_up;
> + }
> +
> + video_set_drvdata(vdev, sd);
> strlcpy(vdev->name, sd->name, sizeof(vdev->name));
> vdev->v4l2_dev = v4l2_dev;
> vdev->fops = &v4l2_subdev_fops;
> - vdev->release = video_device_release_empty;
> + vdev->release = v4l2_device_release_subdev_node;
> vdev->ctrl_handler = sd->ctrl_handler;
> err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
> sd->owner);
> - if (err < 0)
> - return err;
> + if (err < 0) {
> + kfree(vdev);
> + goto clean_up;
> + }
> + get_device(&vdev->dev);
Is get_device() (and the corresponding put_device() calls below) required ? I
thought device_register() initialized the reference count to 1 (don't take my
word for it though).
> #if defined(CONFIG_MEDIA_CONTROLLER)
> sd->entity.v4l.major = VIDEO_MAJOR;
> sd->entity.v4l.minor = vdev->minor;
> #endif
> + sd->devnode = vdev;
> }
> return 0;
> +
> +clean_up:
> + list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
> + if (!sd->devnode)
> + break;
> + video_unregister_device(sd->devnode);
> + put_device(&sd->devnode->dev);
> + }
> +
> + return err;
> }
> EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_nodes);
>
> @@ -245,7 +273,10 @@ void v4l2_device_unregister_subdev(struct v4l2_subdev
> *sd) if (v4l2_dev->mdev)
> media_device_unregister_entity(&sd->entity);
> #endif
> - video_unregister_device(&sd->devnode);
> + if (sd->devnode) {
> + video_unregister_device(sd->devnode);
> + put_device(&sd->devnode->dev);
> + }
> module_put(sd->owner);
> }
> EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);
> diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
> index 257da1a..5dd049a 100644
> --- a/include/media/v4l2-subdev.h
> +++ b/include/media/v4l2-subdev.h
> @@ -534,13 +534,13 @@ struct v4l2_subdev {
> void *dev_priv;
> void *host_priv;
> /* subdev device node */
> - struct video_device devnode;
> + struct video_device *devnode;
> };
>
> #define media_entity_to_v4l2_subdev(ent) \
> container_of(ent, struct v4l2_subdev, entity)
> #define vdev_to_v4l2_subdev(vdev) \
> - container_of(vdev, struct v4l2_subdev, devnode)
> + video_get_drvdata(vdev)
>
> /*
> * Used for storing subdev information per file handle
--
Regards,
Laurent Pinchart
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