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V4L/DVB (9973): v4l2-dev: use the release callback from device instead of cdev

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Instead of relying on the cdev release callback we should rely on the
release callback from the device struct. This requires that we use
get_device/put_device to do proper refcounting. In order to do this
safely v4l2-dev.c now sets up its own file_operations that call
out to the driver's ops.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Hans Verkuil 2008-12-19 21:28:27 -03:00 • committed by Mauro Carvalho Chehab
parent be49e368fb
commit dc93a70cc7
2 changed files with 295 additions and 108 deletions
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47
include/media/v4l2-dev.h
View file

@ -26,6 +26,11 @@
struct v4l2_ioctl_callbacks;
/* Flag to mark the video_device struct as unregistered.
Drivers can set this flag if they want to block all future
device access. It is set by video_unregister_device. */
#define V4L2_FL_UNREGISTERED (0)
/*
* Newer version of video_device, handled by videodev2.c
* This version moves redundant code from video device code to
@ -39,15 +44,17 @@ struct video_device
/* sysfs */
struct device dev; /* v4l device */
struct cdev cdev; /* character device */
void (*cdev_release)(struct kobject *kobj);
struct cdev *cdev; /* character device */
struct device *parent; /* device parent */
/* device info */
char name[32];
int vfl_type;
/* 'minor' is set to -1 if the registration failed */
int minor;
u16 num;
/* use bitops to set/clear/test flags */
unsigned long flags;
/* attribute to differentiate multiple indices on one physical device */
int index;
@ -58,7 +65,7 @@ struct video_device
v4l2_std_id current_norm; /* Current tvnorm */
/* callbacks */
void (*release)(struct video_device *vfd);
void (*release)(struct video_device *vdev);
/* ioctl callbacks */
const struct v4l2_ioctl_ops *ioctl_ops;
@ -67,36 +74,41 @@ struct video_device
/* dev to video-device */
#define to_video_device(cd) container_of(cd, struct video_device, dev)
/* Register and unregister devices. Note that if video_register_device fails,
/* Register video devices. Note that if video_register_device fails,
the release() callback of the video_device structure is *not* called, so
the caller is responsible for freeing any data. Usually that means that
you call video_device_release() on failure. */
int __must_check video_register_device(struct video_device *vfd, int type, int nr);
int __must_check video_register_device_index(struct video_device *vfd,
you call video_device_release() on failure.
Also note that vdev->minor is set to -1 if the registration failed. */
int __must_check video_register_device(struct video_device *vdev, int type, int nr);
int __must_check video_register_device_index(struct video_device *vdev,
int type, int nr, int index);
void video_unregister_device(struct video_device *vfd);
/* Unregister video devices. Will do nothing if vdev == NULL or
vdev->minor < 0. */
void video_unregister_device(struct video_device *vdev);
/* helper functions to alloc/release struct video_device, the
latter can also be used for video_device->release(). */
struct video_device * __must_check video_device_alloc(void);
/* this release function frees the vfd pointer */
void video_device_release(struct video_device *vfd);
/* this release function frees the vdev pointer */
void video_device_release(struct video_device *vdev);
/* this release function does nothing, use when the video_device is a
static global struct. Note that having a static video_device is
a dubious construction at best. */
void video_device_release_empty(struct video_device *vfd);
void video_device_release_empty(struct video_device *vdev);
/* helper functions to access driver private data. */
static inline void *video_get_drvdata(struct video_device *dev)
static inline void *video_get_drvdata(struct video_device *vdev)
{
return dev_get_drvdata(&dev->dev);
return dev_get_drvdata(&vdev->dev);
}
static inline void video_set_drvdata(struct video_device *dev, void *data)
static inline void video_set_drvdata(struct video_device *vdev, void *data)
{
dev_set_drvdata(&dev->dev, data);
dev_set_drvdata(&vdev->dev, data);
}
struct video_device *video_devdata(struct file *file);
@ -108,4 +120,9 @@ static inline void *video_drvdata(struct file *file)
return video_get_drvdata(video_devdata(file));
}
static inline int video_is_unregistered(struct video_device *vdev)
{
return test_bit(V4L2_FL_UNREGISTERED, &vdev->flags);
}
#endif /* _V4L2_DEV_H */