Hi Ricardo,
Thank you for the patch.
On Thu, Feb 06, 2025 at 07:47:00PM +0000, Ricardo Ribalda wrote:
> Add a variable in the file handle state to figure out if a camera is in
> the streaming state or not.
s/\n/ / (and reflow) or s/$/\n/ depending on what you meant.
> This variable will be used in the future for power management policies.
>
> Now that we are at it, make use of guards to simplify the code.
>
> Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> ---
> drivers/media/usb/uvc/uvc_v4l2.c | 15 +++++++++++----
> drivers/media/usb/uvc/uvcvideo.h | 1 +
> 2 files changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
> index 93c6cdb23881..856eaa23e703 100644
> --- a/drivers/media/usb/uvc/uvc_v4l2.c
> +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> @@ -835,11 +835,17 @@ static int uvc_ioctl_streamon(struct file *file, void *fh,
> if (!uvc_has_privileges(handle))
> return -EBUSY;
>
> - mutex_lock(&stream->mutex);
> + guard(mutex)(&stream->mutex);
> +
> + if (handle->is_streaming)
> + return 0;
> +
> ret = uvc_queue_streamon(&stream->queue, type);
> - mutex_unlock(&stream->mutex);
> + if (!ret)
> + handle->is_streaming = true;
>
> return ret;
Now that you use a mutex guard, you can write
if (ret)
return ret;
handle->is_streaming = true;
return 0;
apart from that,
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> +
> }
>
> static int uvc_ioctl_streamoff(struct file *file, void *fh,
> @@ -851,9 +857,10 @@ static int uvc_ioctl_streamoff(struct file *file, void *fh,
> if (!uvc_has_privileges(handle))
> return -EBUSY;
>
> - mutex_lock(&stream->mutex);
> + guard(mutex)(&stream->mutex);
> +
> uvc_queue_streamoff(&stream->queue, type);
> - mutex_unlock(&stream->mutex);
> + handle->is_streaming = false;
>
> return 0;
> }
> diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> index 5e388f05f3fc..bc87e1f2c669 100644
> --- a/drivers/media/usb/uvc/uvcvideo.h
> +++ b/drivers/media/usb/uvc/uvcvideo.h
> @@ -618,6 +618,7 @@ struct uvc_fh {
> struct uvc_streaming *stream;
> enum uvc_handle_state state;
> unsigned int pending_async_ctrls;
> + bool is_streaming;
> };
>
> struct uvc_driver {
--
Regards,
Laurent Pinchart