V4L2 File handles
-----------------
-struct v4l2_fh provides a way to easily keep file handle specific
-data that is used by the V4L2 framework.
-
-.. attention::
- New drivers must use struct v4l2_fh
- since it is also used to implement priority handling
- (:ref:`VIDIOC_G_PRIORITY`).
+struct v4l2_fh provides a way to easily keep file handle specific data that is
+used by the V4L2 framework. Its usage is mandatory in all drivers.
struct v4l2_fh is allocated in the driver's ``open()`` file operation handler.
It is typically embedded in a larger driver-specific structure. The
- Same, but it calls v4l2_fh_is_singular with filp->private_data.
-.. note::
- The V4L2 framework knows whether a driver uses :c:type:`v4l2_fh` as its
- ``file->private_data`` pointer by testing the ``V4L2_FL_USES_V4L2_FH``
- bit in :c:type:`video_device`->flags. This bit is set whenever
- :c:func:`v4l2_fh_init` is called.
-
V4L2 fh functions and data structures
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
如果 video_device 标志，新驱动
必须使用 v4l2_fh 结构体，因为它也用于实现优先级处理（VIDIOC_G/S_PRIORITY）。
-v4l2_fh 的用户（位于 V4l2 框架中，并非驱动）可通过测试
-video_device->flags 中的 V4L2_FL_USES_V4L2_FH 位得知驱动是否使用
-v4l2_fh 作为他的 file->private_data 指针。这个位会在调用 v4l2_fh_init()
-时被设置。
-
v4l2_fh 结构体作为驱动自身文件句柄结构体的一部分被分配，且驱动在
其打开函数中将 file->private_data 指向它。
__poll_t vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait)
{
- struct video_device *vfd = video_devdata(file);
+ struct v4l2_fh *fh = file_to_v4l2_fh(file);
__poll_t res;
res = vb2_core_poll(q, file, wait);
- if (test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags)) {
- struct v4l2_fh *fh = file_to_v4l2_fh(file);
-
- poll_wait(file, &fh->wait, wait);
- if (v4l2_event_pending(fh))
- res |= EPOLLPRI;
- }
+ poll_wait(file, &fh->wait, wait);
+ if (v4l2_event_pending(fh))
+ res |= EPOLLPRI;
return res;
}
static inline bool ctrl_is_pointer(struct file *file, u32 id)
{
struct video_device *vdev = video_devdata(file);
- struct v4l2_fh *fh = NULL;
+ struct v4l2_fh *fh = file_to_v4l2_fh(file);
struct v4l2_ctrl_handler *hdl = NULL;
struct v4l2_query_ext_ctrl qec = { id };
const struct v4l2_ioctl_ops *ops = vdev->ioctl_ops;
- if (test_bit(V4L2_FL_USES_V4L2_FH, &vdev->flags))
- fh = file_to_v4l2_fh(file);
-
- if (fh && fh->ctrl_handler)
+ if (fh->ctrl_handler)
hdl = fh->ctrl_handler;
else if (vdev->ctrl_handler)
hdl = vdev->ctrl_handler;
{
struct video_device *vfd = video_devdata(file);
- if (test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) && vfd->v4l2_dev) {
+ if (vfd->v4l2_dev) {
struct v4l2_fh *vfh = file_to_v4l2_fh(file);
v4l2_ctrl_handler_log_status(vfh->ctrl_handler,
video_get(vdev);
mutex_unlock(&videodev_lock);
- if (video_is_registered(vdev))
- ret = vdev->fops->open(filp);
- else
+ if (!video_is_registered(vdev)) {
+ ret = -ENODEV;
+ goto done;
+ }
+
+ ret = vdev->fops->open(filp);
+ if (ret)
+ goto done;
+
+ /* All drivers must use v4l2_fh. */
+ if (WARN_ON(!test_bit(V4L2_FL_USES_V4L2_FH, &vdev->flags))) {
+ vdev->fops->release(filp);
ret = -ENODEV;
+ }
+done:
if (vdev->dev_debug & V4L2_DEV_DEBUG_FOP)
dprintk("%s: open (%d)\n",
video_device_node_name(vdev), ret);
+
/* decrease the refcount in case of an error */
if (ret)
video_put(vdev);
*/
clear_bit(V4L2_FL_REGISTERED, &vdev->flags);
mutex_unlock(&videodev_lock);
- if (test_bit(V4L2_FL_USES_V4L2_FH, &vdev->flags))
- v4l2_event_wake_all(vdev);
+ v4l2_event_wake_all(vdev);
device_unregister(&vdev->dev);
}
EXPORT_SYMBOL(video_unregister_device);
u32 *p = arg;
vfd = video_devdata(file);
- if (!test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags))
- return -ENOTTY;
vfh = file_to_v4l2_fh(file);
return v4l2_prio_change(vfd->prio, &vfh->prio, *p);
}
struct video_device *vfd = video_devdata(file);
struct v4l2_query_ext_ctrl qec = {};
struct v4l2_queryctrl *p = arg;
- struct v4l2_fh *vfh =
- test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) ? fh : NULL;
+ struct v4l2_fh *vfh = fh;
int ret;
if (vfh && vfh->ctrl_handler)
{
struct video_device *vfd = video_devdata(file);
struct v4l2_query_ext_ctrl *p = arg;
- struct v4l2_fh *vfh =
- test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) ? fh : NULL;
+ struct v4l2_fh *vfh = fh;
if (vfh && vfh->ctrl_handler)
return v4l2_query_ext_ctrl(vfh->ctrl_handler, p);
{
struct video_device *vfd = video_devdata(file);
struct v4l2_querymenu *p = arg;
- struct v4l2_fh *vfh =
- test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) ? fh : NULL;
+ struct v4l2_fh *vfh = fh;
if (vfh && vfh->ctrl_handler)
return v4l2_querymenu(vfh->ctrl_handler, p);
{
struct video_device *vfd = video_devdata(file);
struct v4l2_control *p = arg;
- struct v4l2_fh *vfh =
- test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) ? fh : NULL;
+ struct v4l2_fh *vfh = fh;
struct v4l2_ext_controls ctrls;
struct v4l2_ext_control ctrl;
{
struct video_device *vfd = video_devdata(file);
struct v4l2_control *p = arg;
- struct v4l2_fh *vfh =
- test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) ? fh : NULL;
+ struct v4l2_fh *vfh = fh;
struct v4l2_ext_controls ctrls;
struct v4l2_ext_control ctrl;
int ret;
{
struct video_device *vfd = video_devdata(file);
struct v4l2_ext_controls *p = arg;
- struct v4l2_fh *vfh =
- test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) ? fh : NULL;
+ struct v4l2_fh *vfh = fh;
p->error_idx = p->count;
if (vfh && vfh->ctrl_handler)
{
struct video_device *vfd = video_devdata(file);
struct v4l2_ext_controls *p = arg;
- struct v4l2_fh *vfh =
- test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) ? fh : NULL;
+ struct v4l2_fh *vfh = fh;
p->error_idx = p->count;
if (vfh && vfh->ctrl_handler)
{
struct video_device *vfd = video_devdata(file);
struct v4l2_ext_controls *p = arg;
- struct v4l2_fh *vfh =
- test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) ? fh : NULL;
+ struct v4l2_fh *vfh = fh;
p->error_idx = p->count;
if (vfh && vfh->ctrl_handler)
struct v4l2_ioctl_info default_info;
const struct v4l2_ioctl_info *info;
void *fh = file->private_data;
- struct v4l2_fh *vfh = NULL;
+ struct v4l2_fh *vfh = file_to_v4l2_fh(file);
int dev_debug = vfd->dev_debug;
long ret = -ENOTTY;
return ret;
}
- if (test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags))
- vfh = file_to_v4l2_fh(file);
-
/*
* We need to serialize streamon/off with queueing new requests.
* These ioctls may trigger the cancellation of a streaming
info = &v4l2_ioctls[_IOC_NR(cmd)];
if (!is_valid_ioctl(vfd, cmd) &&
- !((info->flags & INFO_FL_CTRL) && vfh && vfh->ctrl_handler))
+ !((info->flags & INFO_FL_CTRL) && vfh->ctrl_handler))
goto done;
- if (vfh && (info->flags & INFO_FL_PRIO)) {
+ if (info->flags & INFO_FL_PRIO) {
ret = v4l2_prio_check(vfd->prio, vfh->prio);
if (ret)
goto done;
ret = -ENOTTY;
} else {
ret = ops->vidioc_default(file, fh,
- vfh ? v4l2_prio_check(vfd->prio, vfh->prio) >= 0 : 0,
+ v4l2_prio_check(vfd->prio, vfh->prio) >= 0,
cmd, arg);
}
__poll_t v4l2_m2m_poll(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
struct poll_table_struct *wait)
{
- struct video_device *vfd = video_devdata(file);
+ struct v4l2_fh *fh = file_to_v4l2_fh(file);
struct vb2_queue *src_q = v4l2_m2m_get_src_vq(m2m_ctx);
struct vb2_queue *dst_q = v4l2_m2m_get_dst_vq(m2m_ctx);
__poll_t req_events = poll_requested_events(wait);
if (req_events & (EPOLLOUT | EPOLLWRNORM | EPOLLIN | EPOLLRDNORM))
rc = v4l2_m2m_poll_for_data(file, m2m_ctx, wait);
- if (test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags)) {
- struct v4l2_fh *fh = file_to_v4l2_fh(file);
-
- poll_wait(file, &fh->wait, wait);
- if (v4l2_event_pending(fh))
- rc |= EPOLLPRI;
- }
+ poll_wait(file, &fh->wait, wait);
+ if (v4l2_event_pending(fh))
+ rc |= EPOLLPRI;
return rc;
}
* @V4L2_FL_USES_V4L2_FH:
* indicates that file->private_data points to &struct v4l2_fh.
* This flag is set by the core when v4l2_fh_init() is called.
- * All new drivers should use it.
+ * All drivers must use it.
* @V4L2_FL_QUIRK_INVERTED_CROP:
* some old M2M drivers use g/s_crop/cropcap incorrectly: crop and
* compose are swapped. If this flag is set, then the selection
* v4l2-fh.h
*
* V4L2 file handle. Store per file handle data for the V4L2
- * framework. Using file handles is optional for the drivers.
+ * framework. Using file handles is mandatory for the drivers.
*
* Copyright (C) 2009--2010 Nokia Corporation.
*
projects / thirdparty / linux.git / commitdiff
