Hi Laurent,
Quoting Laurent Pinchart (2022-03-18 21:14:44)
> vb2 queue ownership is managed by the ioctl handler helpers
> (vb2_ioctl_*). There are however use cases where drivers can benefit
> from checking queue ownership, for instance when open-coding an ioctl
> handler that needs to perform additional checks before calling the
> corresponding vb2 operation.
>
> Expose the vb2_queue_is_busy() function in the videobuf2-v4l2.h header,
> and change its first argument to a struct vb2_queue pointer as the
> function name implies it operates on a queue, not a video_device.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
> ---
> .../media/common/videobuf2/videobuf2-v4l2.c | 26 +++++++------------
> include/media/videobuf2-v4l2.h | 23 ++++++++++++++--
> 2 files changed, 31 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> index 6edf4508c636..075d24ebf44c 100644
> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> @@ -977,12 +977,6 @@ EXPORT_SYMBOL_GPL(vb2_poll);
> * and so they simplify the driver code.
> */
>
> -/* The queue is busy if there is a owner and you are not that owner. */
> -static inline bool vb2_queue_is_busy(struct video_device *vdev, struct file *file)
> -{
> - return vdev->queue->owner && vdev->queue->owner != file->private_data;
> -}
> -
> /* vb2 ioctl helpers */
>
> int vb2_ioctl_reqbufs(struct file *file, void *priv,
> @@ -997,7 +991,7 @@ int vb2_ioctl_reqbufs(struct file *file, void *priv,
> p->flags = flags;
> if (res)
> return res;
> - if (vb2_queue_is_busy(vdev, file))
> + if (vb2_queue_is_busy(vdev->queue, file))
> return -EBUSY;
> res = vb2_core_reqbufs(vdev->queue, p->memory, p->flags, &p->count);
> /* If count == 0, then the owner has released all buffers and he
> @@ -1026,7 +1020,7 @@ int vb2_ioctl_create_bufs(struct file *file, void *priv,
> return res != -EBUSY ? res : 0;
> if (res)
> return res;
> - if (vb2_queue_is_busy(vdev, file))
> + if (vb2_queue_is_busy(vdev->queue, file))
> return -EBUSY;
>
> res = vb2_create_bufs(vdev->queue, p);
> @@ -1041,7 +1035,7 @@ int vb2_ioctl_prepare_buf(struct file *file, void *priv,
> {
> struct video_device *vdev = video_devdata(file);
>
> - if (vb2_queue_is_busy(vdev, file))
> + if (vb2_queue_is_busy(vdev->queue, file))
> return -EBUSY;
> return vb2_prepare_buf(vdev->queue, vdev->v4l2_dev->mdev, p);
> }
> @@ -1060,7 +1054,7 @@ int vb2_ioctl_qbuf(struct file *file, void *priv, struct v4l2_buffer *p)
> {
> struct video_device *vdev = video_devdata(file);
>
> - if (vb2_queue_is_busy(vdev, file))
> + if (vb2_queue_is_busy(vdev->queue, file))
> return -EBUSY;
> return vb2_qbuf(vdev->queue, vdev->v4l2_dev->mdev, p);
> }
> @@ -1070,7 +1064,7 @@ int vb2_ioctl_dqbuf(struct file *file, void *priv, struct v4l2_buffer *p)
> {
> struct video_device *vdev = video_devdata(file);
>
> - if (vb2_queue_is_busy(vdev, file))
> + if (vb2_queue_is_busy(vdev->queue, file))
> return -EBUSY;
> return vb2_dqbuf(vdev->queue, p, file->f_flags & O_NONBLOCK);
> }
> @@ -1080,7 +1074,7 @@ int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i)
> {
> struct video_device *vdev = video_devdata(file);
>
> - if (vb2_queue_is_busy(vdev, file))
> + if (vb2_queue_is_busy(vdev->queue, file))
> return -EBUSY;
> return vb2_streamon(vdev->queue, i);
> }
> @@ -1090,7 +1084,7 @@ int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i)
> {
> struct video_device *vdev = video_devdata(file);
>
> - if (vb2_queue_is_busy(vdev, file))
> + if (vb2_queue_is_busy(vdev->queue, file))
> return -EBUSY;
> return vb2_streamoff(vdev->queue, i);
> }
> @@ -1100,7 +1094,7 @@ int vb2_ioctl_expbuf(struct file *file, void *priv, struct v4l2_exportbuffer *p)
> {
> struct video_device *vdev = video_devdata(file);
>
> - if (vb2_queue_is_busy(vdev, file))
> + if (vb2_queue_is_busy(vdev->queue, file))
> return -EBUSY;
> return vb2_expbuf(vdev->queue, p);
> }
> @@ -1152,7 +1146,7 @@ ssize_t vb2_fop_write(struct file *file, const char __user *buf,
> return -EINVAL;
> if (lock && mutex_lock_interruptible(lock))
> return -ERESTARTSYS;
> - if (vb2_queue_is_busy(vdev, file))
> + if (vb2_queue_is_busy(vdev->queue, file))
> goto exit;
> err = vb2_write(vdev->queue, buf, count, ppos,
> file->f_flags & O_NONBLOCK);
> @@ -1176,7 +1170,7 @@ ssize_t vb2_fop_read(struct file *file, char __user *buf,
> return -EINVAL;
> if (lock && mutex_lock_interruptible(lock))
> return -ERESTARTSYS;
> - if (vb2_queue_is_busy(vdev, file))
> + if (vb2_queue_is_busy(vdev->queue, file))
> goto exit;
> err = vb2_read(vdev->queue, buf, count, ppos,
> file->f_flags & O_NONBLOCK);
> diff --git a/include/media/videobuf2-v4l2.h b/include/media/videobuf2-v4l2.h
> index b66585e304e2..1fb99583cd45 100644
> --- a/include/media/videobuf2-v4l2.h
> +++ b/include/media/videobuf2-v4l2.h
> @@ -302,10 +302,29 @@ __poll_t vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait);
> * The following functions are not part of the vb2 core API, but are simple
> * helper functions that you can use in your struct v4l2_file_operations,
> * struct v4l2_ioctl_ops and struct vb2_ops. They will serialize if vb2_queue->lock
> - * or video_device->lock is set, and they will set and test vb2_queue->owner
> - * to check if the calling filehandle is permitted to do the queuing operation.
> + * or video_device->lock is set, and they will set and test the queue owner
> + * (vb2_queue->owner) to check if the calling filehandle is permitted to do the
> + * queuing operation.
> */
>
> +/**
> + * vb2_queue_is_busy() - check if the queue is busy
> + * @q: pointer to &struct vb2_queue with videobuf2 queue.
> + * @file: file through which the vb2 queue access is performed
> + *
> + * The queue is considered busy if is has an owner and the owner is not the
if it has
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx>
> + * @file.
> + *
> + * Queue ownership is acquired and checked by some of the v4l2_ioctl_ops helpers
> + * below. Drivers can also use this function directly when they need to
> + * open-code ioctl handlers, for instance to add additional checks between the
> + * queue ownership test and the call to the corresponding vb2 operation.
> + */
> +static inline bool vb2_queue_is_busy(struct vb2_queue *q, struct file *file)
> +{
> + return q->owner && q->owner != file->private_data;
> +}
> +
> /* struct v4l2_ioctl_ops helpers */
>
> int vb2_ioctl_reqbufs(struct file *file, void *priv,
> --
> Regards,
>
> Laurent Pinchart
>
