[media] v4l2-dev/ioctl.c: add vb2_queue support to video_device

This prepares struct video_device for easier integration with vb2.

It also introduces a new lock that protects the vb2_queue. It is up
to the driver to use it or not. And the driver can associate an owner
filehandle with the queue to check whether queuing requests are
permitted for the calling filehandle.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

3 files changed, 21 insertions, 0 deletions

diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h
index a056e6e..5c416cd 100644
--- a/include/media/v4l2-dev.h
+++ b/include/media/v4l2-dev.h
@@ -100,6 +100,9 @@ struct video_device
 	/* Control handler associated with this device node. May be NULL. */
 	struct v4l2_ctrl_handler *ctrl_handler;
 
+	/* vb2_queue associated with this device node. May be NULL. */
+	struct vb2_queue *queue;
+
 	/* Priority state. If NULL, then v4l2_dev->prio will be used. */
 	struct v4l2_prio_state *prio;
 
diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h
index dfd984f..19e9352 100644
--- a/include/media/v4l2-ioctl.h
+++ b/include/media/v4l2-ioctl.h
@@ -304,6 +304,11 @@ extern int v4l2_video_std_construct(struct v4l2_standard *vs,
    then do printk(KERN_DEBUG "%s: ", prefix) first. */
 extern void v4l_printk_ioctl(const char *prefix, unsigned int cmd);
 
+/* Internal use only: get the mutex (if any) that we need to lock for the
+   given command. */
+struct video_device;
+extern struct mutex *v4l2_ioctl_get_lock(struct video_device *vdev, unsigned cmd);
+
 /* names for fancy debug output */
 extern const char *v4l2_field_names[];
 extern const char *v4l2_type_names[];
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index a15d1f1..924e95e 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -244,12 +244,23 @@ struct vb2_ops {
 	void (*buf_queue)(struct vb2_buffer *vb);
 };
 
+struct v4l2_fh;
+
 /**
  * struct vb2_queue - a videobuf queue
  *
  * @type:	queue type (see V4L2_BUF_TYPE_* in linux/videodev2.h
  * @io_modes:	supported io methods (see vb2_io_modes enum)
  * @io_flags:	additional io flags (see vb2_fileio_flags enum)
+ * @lock:	pointer to a mutex that protects the vb2_queue struct. The
+ *		driver can set this to a mutex to let the v4l2 core serialize
+ *		the queuing ioctls. If the driver wants to handle locking
+ *		itself, then this should be set to NULL. This lock is not used
+ *		by the videobuf2 core API.
+ * @owner:	The filehandle that 'owns' the buffers, i.e. the filehandle
+ *		that called reqbufs, create_buffers or started fileio.
+ *		This field is not used by the videobuf2 core API, but it allows
+ *		drivers to easily associate an owner filehandle with the queue.
  * @ops:	driver-specific callbacks
  * @mem_ops:	memory allocator specific callbacks
  * @drv_priv:	driver private data
@@ -273,6 +284,8 @@ struct vb2_queue {
 	enum v4l2_buf_type		type;
 	unsigned int			io_modes;
 	unsigned int			io_flags;
+	struct mutex			*lock;
+	struct v4l2_fh			*owner;
 
 	const struct vb2_ops		*ops;
 	const struct vb2_mem_ops	*mem_ops;