linux-kernel - Re: [PATCH] media: v4l2-ctrl: Fix flags field on Control events

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Date:   Tue, 17 Oct 2017 17:37:54 +0200
From:   Hans Verkuil <hverkuil@...all.nl>
To:     Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>,
        linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] media: v4l2-ctrl: Fix flags field on Control events

On 10/17/2017 04:53 PM, Ricardo Ribalda Delgado wrote:
> VIDIOC_DQEVENT and VIDIOC_QUERY_EXT_CTRL should give the same output for
> the control flags field.
> 
> This patch creates a new function user_flags(), that calculates the user
> exported flags value (which is different than the kernel internal flags
> structure). This function is then used by all the code that exports the
> internal flags to userspace.
> 
> Reported-by: Dimitrios Katsaros <patcherwork@...il.com>
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>
> ---
> 
> Maybe we should cc stable on this one.
> 
>  drivers/media/v4l2-core/v4l2-ctrls.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
> index 4e53a8654690..751cf5746f90 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> @@ -1227,6 +1227,16 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
>  }
>  EXPORT_SYMBOL(v4l2_ctrl_fill);
>  
> +static u32 user_flags(struct v4l2_ctrl *ctrl)

Add const:

static u32 user_flags(const struct v4l2_ctrl *ctrl)

Other than that it looks good.

	Hans

> +{
> +	u32 flags = ctrl->flags;
> +
> +	if (ctrl->is_ptr)
> +		flags |= V4L2_CTRL_FLAG_HAS_PAYLOAD;
> +
> +	return flags;
> +}
> +
>  static void fill_event(struct v4l2_event *ev, struct v4l2_ctrl *ctrl, u32 changes)
>  {
>  	memset(ev->reserved, 0, sizeof(ev->reserved));
> @@ -1234,7 +1244,7 @@ static void fill_event(struct v4l2_event *ev, struct v4l2_ctrl *ctrl, u32 change
>  	ev->id = ctrl->id;
>  	ev->u.ctrl.changes = changes;
>  	ev->u.ctrl.type = ctrl->type;
> -	ev->u.ctrl.flags = ctrl->flags;
> +	ev->u.ctrl.flags = user_flags(ctrl);
>  	if (ctrl->is_ptr)
>  		ev->u.ctrl.value64 = 0;
>  	else
> @@ -2577,10 +2587,8 @@ int v4l2_query_ext_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_query_ext_ctr
>  	else
>  		qc->id = ctrl->id;
>  	strlcpy(qc->name, ctrl->name, sizeof(qc->name));
> -	qc->flags = ctrl->flags;
> +	qc->flags = user_flags(ctrl);
>  	qc->type = ctrl->type;
> -	if (ctrl->is_ptr)
> -		qc->flags |= V4L2_CTRL_FLAG_HAS_PAYLOAD;
>  	qc->elem_size = ctrl->elem_size;
>  	qc->elems = ctrl->elems;
>  	qc->nr_of_dims = ctrl->nr_of_dims;
>