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[media] v4l2-fh: add v4l2_fh_open and v4l2_fh_release helper functions 

Add two new functions: v4l2_fh_open allocates and initializes a struct v4l2_fh
based on a struct file pointer and v4l2_fh_release releases and frees a struct
v4l2_fh.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Hans Verkuil 2011-01-08 09:36:04 -03:00 committed by Mauro Carvalho Chehab
parent fc5602be7c
commit 73cb42068c
2 changed files with 43 additions and 0 deletions
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28
drivers/media/video/v4l2-fh.c
View File

@ -23,6 +23,7 @@
*/
#include <linux/bitops.h>
#include <linux/slab.h>
#include <media/v4l2-dev.h>
#include <media/v4l2-fh.h>
#include <media/v4l2-event.h>
@ -60,6 +61,20 @@ void v4l2_fh_add(struct v4l2_fh *fh)
}
EXPORT_SYMBOL_GPL(v4l2_fh_add);
int v4l2_fh_open(struct file *filp)
{
struct video_device *vdev = video_devdata(filp);
struct v4l2_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL);
filp->private_data = fh;
if (fh == NULL)
return -ENOMEM;
v4l2_fh_init(fh, vdev);
v4l2_fh_add(fh);
return 0;
}
EXPORT_SYMBOL_GPL(v4l2_fh_open);
void v4l2_fh_del(struct v4l2_fh *fh)
{
unsigned long flags;
@ -81,3 +96,16 @@ void v4l2_fh_exit(struct v4l2_fh *fh)
v4l2_event_free(fh);
}
EXPORT_SYMBOL_GPL(v4l2_fh_exit);
int v4l2_fh_release(struct file *filp)
{
struct v4l2_fh *fh = filp->private_data;
if (fh) {
v4l2_fh_del(fh);
v4l2_fh_exit(fh);
kfree(fh);
}
return 0;
}
EXPORT_SYMBOL_GPL(v4l2_fh_release);

15
include/media/v4l2-fh.h
View File

@ -50,9 +50,17 @@ int v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev);
* handle must be initialised first.
*/
void v4l2_fh_add(struct v4l2_fh *fh);
/*
* Can be used as the open() op of v4l2_file_operations.
* It allocates a v4l2_fh and inits and adds it to the video_device associated
* with the file pointer.
*/
int v4l2_fh_open(struct file *filp);
/*
* Remove file handle from the list of file handles. Must be called in
* v4l2_file_operations->release() handler if the driver uses v4l2_fh.
* On error filp->private_data will be NULL, otherwise it will point to
* the v4l2_fh struct.
*/
void v4l2_fh_del(struct v4l2_fh *fh);
/*
@ -62,5 +70,12 @@ void v4l2_fh_del(struct v4l2_fh *fh);
* driver uses v4l2_fh.
*/
void v4l2_fh_exit(struct v4l2_fh *fh);
/*
* Can be used as the release() op of v4l2_file_operations.
* It deletes and exits the v4l2_fh associated with the file pointer and
* frees it. It will do nothing if filp->private_data (the pointer to the
* v4l2_fh struct) is NULL. This function always returns 0.
*/
int v4l2_fh_release(struct file *filp);
#endif /* V4L2_EVENT_H */