media: Drop V4L2_FL_USES_V4L2_FH checks

Now that all drivers use v4l2_fh, we can drop the V4L2_FL_USES_V4L2_FH
checks through the V4L2 core.

To ensure that all new drivers use v4l2_fh, keep setting the
V4L2_FL_USES_V4L2_FH flag in v4l2_fh_init(), and verify it is set after
the .open() file operation returns.

Signed-off-by: Laurent Pinchart <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>

Documentation/driver-api/media/v4l2-fh.rst

···
 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
···
 (struct file \*filp)
 
 - 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

Documentation/translations/zh_CN/video4linux/v4l2-framework.txt

···
 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。
 

drivers/media/common/videobuf2/videobuf2-v4l2.c

···
 
 __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;
 }

drivers/media/v4l2-core/v4l2-compat-ioctl32.c

···
 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;

drivers/media/v4l2-core/v4l2-ctrls-api.c

···
 {
 	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,

drivers/media/v4l2-core/v4l2-dev.c

···
 	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);

drivers/media/v4l2-core/v4l2-ioctl.c

···
 	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;
 
···
 				video_device_node_name(vfd));
 		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.
···
 		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);
 	}
 

drivers/media/v4l2-core/v4l2-mem2mem.c

···
 __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;
 }

include/media/v4l2-dev.h

···
  * @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

include/media/v4l2-fh.h

···
  * 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.
  *