Re: [PATCHv17 16/34] v4l2-ctrls: add v4l2_ctrl_request_hdl_find/put/ctrl_find functions

[Mauro Carvalho Chehab <mchehab+samsung@kernel.org>]

Em Sat,  4 Aug 2018 14:45:08 +0200
Hans Verkuil <hverkuil@xs4all.nl> escreveu:

> If a driver needs to find/inspect the controls set in a request then
> it can use these functions.
> 
> E.g. to check if a required control is set in a request use this in the
> req_validate() implementation:
> 
> 	int res = -EINVAL;
> 
> 	hdl = v4l2_ctrl_request_hdl_find(req, parent_hdl);
> 	if (hdl) {
> 		if (v4l2_ctrl_request_hdl_ctrl_find(hdl, ctrl_id))
> 			res = 0;
> 		v4l2_ctrl_request_hdl_put(hdl);
> 	}
> 	return res;
> 
> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
> ---
>  drivers/media/v4l2-core/v4l2-ctrls.c | 25 ++++++++++++++++
>  include/media/v4l2-ctrls.h           | 44 +++++++++++++++++++++++++++-
>  2 files changed, 68 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
> index 86a6ae54ccaa..2a30be824491 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> @@ -2976,6 +2976,31 @@ static const struct media_request_object_ops req_ops = {
>  	.release = v4l2_ctrl_request_release,
>  };
>  
> +struct v4l2_ctrl_handler *v4l2_ctrl_request_hdl_find(struct media_request *req,
> +					struct v4l2_ctrl_handler *parent)
> +{
> +	struct media_request_object *obj;
> +
> +	if (WARN_ON(req->state != MEDIA_REQUEST_STATE_VALIDATING &&
> +		    req->state != MEDIA_REQUEST_STATE_QUEUED))
> +		return NULL;
> +
> +	obj = media_request_object_find(req, &req_ops, parent);
> +	if (obj)
> +		return container_of(obj, struct v4l2_ctrl_handler, req_obj);
> +	return NULL;
> +}
> +EXPORT_SYMBOL_GPL(v4l2_ctrl_request_hdl_find);
> +
> +struct v4l2_ctrl *
> +v4l2_ctrl_request_hdl_ctrl_find(struct v4l2_ctrl_handler *hdl, u32 id)
> +{
> +	struct v4l2_ctrl_ref *ref = find_ref_lock(hdl, id);
> +
> +	return (ref && ref->req == ref) ? ref->ctrl : NULL;

Doesn't those helper functions (including this one) be serialized?

> +}
> +EXPORT_SYMBOL_GPL(v4l2_ctrl_request_hdl_ctrl_find);
> +
>  static int v4l2_ctrl_request_bind(struct media_request *req,
>  			   struct v4l2_ctrl_handler *hdl,
>  			   struct v4l2_ctrl_handler *from)
> diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
> index 98b1e70a4a46..aeb7f3c24ef7 100644
> --- a/include/media/v4l2-ctrls.h
> +++ b/include/media/v4l2-ctrls.h
> @@ -1111,7 +1111,49 @@ void v4l2_ctrl_request_setup(struct media_request *req,
>   * request object.
>   */
>  void v4l2_ctrl_request_complete(struct media_request *req,
> -				struct v4l2_ctrl_handler *hdl);
> +				struct v4l2_ctrl_handler *parent);
> +
> +/**
> + * v4l2_ctrl_request_hdl_find - Find the control handler in the request
> + *
> + * @req: The request
> + * @parent: The parent control handler ('priv' in media_request_object_find())
> + *
> + * This function finds the control handler in the request. It may return
> + * NULL if not found. When done, you must call v4l2_ctrl_request_put_hdl()
> + * with the returned handler pointer.
> + *
> + * If the request is not in state VALIDATING or QUEUED, then this function
> + * will always return NULL.
> + */
> +struct v4l2_ctrl_handler *v4l2_ctrl_request_hdl_find(struct media_request *req,
> +					struct v4l2_ctrl_handler *parent);
> +
> +/**
> + * v4l2_ctrl_request_hdl_put - Put the control handler
> + *
> + * @hdl: Put this control handler
> + *
> + * This function released the control handler previously obtained from'
> + * v4l2_ctrl_request_hdl_find().
> + */
> +static inline void v4l2_ctrl_request_hdl_put(struct v4l2_ctrl_handler *hdl)
> +{
> +	if (hdl)
> +		media_request_object_put(&hdl->req_obj);
> +}
> +
> +/**
> + * v4l2_ctrl_request_ctrl_find() - Find a control with the given ID.
> + *
> + * @hdl: The control handler from the request.
> + * @id: The ID of the control to find.
> + *
> + * This function returns a pointer to the control if this control is
> + * part of the request or NULL otherwise.
> + */
> +struct v4l2_ctrl *
> +v4l2_ctrl_request_hdl_ctrl_find(struct v4l2_ctrl_handler *hdl, u32 id);
>  
>  /* Helpers for ioctl_ops */
>  



Thanks,
Mauro