Hi Guennadi,
On Tuesday 13 September 2011 11:26:23 Guennadi Liakhovetski wrote:
> On Tue, 13 Sep 2011, Laurent Pinchart wrote:
> > 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).
>
> Indeed, I think, you're right. Will update.
Please test it as well :-)
--
Regards,
Laurent Pinchart
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
