Re: [PATCH v14 03/11] media: uvcvideo: introduce __uvc_ctrl_get_std()

Laurent Pinchart
2023-12-08T15:12:50Z

Hi Yunke,

Thank you for the patch.

On Fri, Dec 01, 2023 at 04:18:54PM +0900, Yunke Cao wrote:
> Refactor uvc_ctrl to make adding compound control easier.
>
> Currently __uvc_ctrl_get() only work for non-compound controls.
> Move the logic into __uvc_ctrl_std(), return error for compound
> controls.
>
> Make __uvc_ctrl_get() call __uvc_ctrl_std() inside. Also modify some of the
> callers of __uvc_ctrl_get() to call __uvc_ctrl_get_std() instead.
>
> Signed-off-by: Yunke Cao <yunkec@google.com>
> ---
> Changelog since v12:
> - No change.
> Changelog since v11:
> - Minor change to avoid negative if statement.
> Changelog since v10:
> - Better commit message.
> Changelog since v9:
> - No change.
> Changelog since v8:
> - No change.
> Changelog since v7:
> - Newly added patch. Split the refactoring of uvc_ctrl_get from v7 3/7.
>
> drivers/media/usb/uvc/uvc_ctrl.c | 42 +++++++++++++++++++++-----------
> 1 file changed, 28 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> index 8d8333786333..4a685532f7eb 100644
> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> @@ -1081,15 +1081,15 @@ static int __uvc_ctrl_load_cur(struct uvc_video_chain *chain,
> return ret;
> }
>
> -static int __uvc_ctrl_get(struct uvc_video_chain *chain,
> - struct uvc_control *ctrl,
> - struct uvc_control_mapping *mapping,
> - s32 *value)
> +static int __uvc_ctrl_get_std(struct uvc_video_chain *chain,
> + struct uvc_control *ctrl,
> + struct uvc_control_mapping *mapping,
> + s32 *value)
> {
> int ret;
>
> - if ((ctrl->info.flags & UVC_CTRL_FLAG_GET_CUR) == 0)
> - return -EACCES;
> + if (uvc_ctrl_mapping_is_compound(mapping))
> + return -EINVAL;

This duplicates the check that you have added in multiple callers. With
the whole series applied, this function is called without a compound
check from uvc_ctrl_is_accessible() only. I think it would be better to
explicitly handle compound controls there. Even better possible, you
could check at driver initialization time that V4L2 master controls are
never compound controls.

>
> ret = __uvc_ctrl_load_cur(chain, ctrl);
> if (ret < 0)
> @@ -1199,7 +1199,7 @@ int uvc_ctrl_is_accessible(struct uvc_video_chain *chain, u32 v4l2_id,
> if (!master_ctrl || !(master_ctrl->info.flags & UVC_CTRL_FLAG_GET_CUR))
> return 0;
>
> - ret = __uvc_ctrl_get(chain, master_ctrl, master_map, &val);
> + ret = __uvc_ctrl_get_std(chain, master_ctrl, master_map, &val);
> if (ret >= 0 && val != mapping->master_manual)
> return -EACCES;
>
> @@ -1264,8 +1264,13 @@ static int __uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
> __uvc_find_control(ctrl->entity, mapping->master_id,
> &master_map, &master_ctrl, 0);
> if (master_ctrl && (master_ctrl->info.flags & UVC_CTRL_FLAG_GET_CUR)) {
> - s32 val;
> - int ret = __uvc_ctrl_get(chain, master_ctrl, master_map, &val);
> + s32 val = 0;
> + int ret;
> +
> + if (uvc_ctrl_mapping_is_compound(master_map))
> + return -EINVAL;
> +
> + ret = __uvc_ctrl_get_std(chain, master_ctrl, master_map, &val);
> if (ret < 0)
> return ret;
>
> @@ -1532,7 +1537,8 @@ static void uvc_ctrl_send_slave_event(struct uvc_video_chain *chain,
> if (ctrl == NULL)
> return;
>
> - if (__uvc_ctrl_get(chain, ctrl, mapping, &val) == 0)
> + if (uvc_ctrl_mapping_is_compound(mapping) ||
> + __uvc_ctrl_get_std(chain, ctrl, mapping, &val) == 0)
> changes |= V4L2_EVENT_CTRL_CH_VALUE;
>
> uvc_ctrl_send_event(chain, handle, ctrl, mapping, val, changes);
> @@ -1703,7 +1709,8 @@ static int uvc_ctrl_add_event(struct v4l2_subscribed_event *sev, unsigned elems)
> u32 changes = V4L2_EVENT_CTRL_CH_FLAGS;
> s32 val = 0;
>
> - if (__uvc_ctrl_get(handle->chain, ctrl, mapping, &val) == 0)
> + if (uvc_ctrl_mapping_is_compound(mapping) ||
> + __uvc_ctrl_get_std(handle->chain, ctrl, mapping, &val) == 0)
> changes |= V4L2_EVENT_CTRL_CH_VALUE;
>
> uvc_ctrl_fill_event(handle->chain, &ev, ctrl, mapping, val,
> @@ -1883,7 +1890,10 @@ int uvc_ctrl_get(struct uvc_video_chain *chain,
> if (ctrl == NULL)
> return -EINVAL;
>
> - return __uvc_ctrl_get(chain, ctrl, mapping, &xctrl->value);
> + if (uvc_ctrl_mapping_is_compound(mapping))
> + return -EINVAL;
> + else
> + return __uvc_ctrl_get_std(chain, ctrl, mapping, &xctrl->value);
> }
>
> static int __uvc_ctrl_get_boundary_std(struct uvc_video_chain *chain,
> @@ -2042,8 +2052,12 @@ int uvc_ctrl_set(struct uvc_fh *handle,
> ctrl->info.size);
> }
>
> - mapping->set(mapping, value,
> - uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT));
> + if (uvc_ctrl_mapping_is_compound(mapping))
> + return -EINVAL;
> + else
> + mapping->set(mapping, value,
> + uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT));

This seems unrelated to the commit message.

> +
>
> if (ctrl->info.flags & UVC_CTRL_FLAG_ASYNCHRONOUS)
> ctrl->handle = handle;

--
Regards,

Laurent Pinchart