diff options
| author | Hans Verkuil <hverkuil@xs4all.nl> | 2011-03-12 06:37:19 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2011-03-22 16:38:05 -0300 |
| commit | bedf8bcf6b4f90a6e31add3721a2e71877289381 (patch) | |
| tree | 855560191d12dc9f21db59fca801c67f036b5167 /drivers/media/video/v4l2-device.c | |
| parent | a64bb4b7111e063154f97ff64dab03144cdfb5d9 (diff) | |
[media] v4l2-device: add kref and a release function
The video_device struct has proper ref counting and its release function
will be called when the last user releases it. But no such support was
available for struct v4l2_device. This made it hard to determine when a
USB driver can release the device if it has multiple device nodes.
With one device node it is easy of course, since when the device node is
released, the whole device can be released.
This patch adds refcounting to v4l2_device. When registering device nodes
the v4l2_device refcount will be increased, when releasing device nodes
it will be decreased. The (optional) release function will be called when
the last device node was released.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media/video/v4l2-device.c')
| -rw-r--r-- | drivers/media/video/v4l2-device.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/media/video/v4l2-device.c b/drivers/media/video/v4l2-device.c index fd7a445ce34..5aeaf876ba9 100644 --- a/drivers/media/video/v4l2-device.c +++ b/drivers/media/video/v4l2-device.c @@ -37,6 +37,7 @@ int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev) spin_lock_init(&v4l2_dev->lock); mutex_init(&v4l2_dev->ioctl_lock); v4l2_prio_init(&v4l2_dev->prio); + kref_init(&v4l2_dev->ref); v4l2_dev->dev = dev; if (dev == NULL) { /* If dev == NULL, then name must be filled in by the caller */ @@ -54,6 +55,21 @@ int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev) } EXPORT_SYMBOL_GPL(v4l2_device_register); +static void v4l2_device_release(struct kref *ref) +{ + struct v4l2_device *v4l2_dev = + container_of(ref, struct v4l2_device, ref); + + if (v4l2_dev->release) + v4l2_dev->release(v4l2_dev); +} + +int v4l2_device_put(struct v4l2_device *v4l2_dev) +{ + return kref_put(&v4l2_dev->ref, v4l2_device_release); +} +EXPORT_SYMBOL_GPL(v4l2_device_put); + int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename, atomic_t *instance) { |