Re: [PATCH v4 2/3] media: v4l2-ctrls: Return the handler's error in v4l2_ctrl_handler_free()

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Sakari,

Thank you for the patch.

On Mon, Jun 23, 2025 at 03:23:13PM +0300, Sakari Ailus wrote:
> v4l2_ctrl_handler_free() used to return void but changing this to int,
> returning the handler's error code, enables the drivers to simply return
> the handler's error in this common error handling pattern:
> 
> 	if (handler->error)
> 		return v4l2_ctrl_handler_free(handler);
> 
> Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> ---
>  drivers/media/v4l2-core/v4l2-ctrls-core.c | 11 ++++++++---
>  include/media/v4l2-ctrls.h                |  4 +++-
>  2 files changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls-core.c b/drivers/media/v4l2-core/v4l2-ctrls-core.c
> index d28596c720d8..98b960775e87 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls-core.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls-core.c
> @@ -1631,14 +1631,17 @@ int v4l2_ctrl_handler_init_class(struct v4l2_ctrl_handler *hdl,
>  EXPORT_SYMBOL(v4l2_ctrl_handler_init_class);
>  
>  /* Free all controls and control refs */
> -void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl)
> +int v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl)
>  {
>  	struct v4l2_ctrl_ref *ref, *next_ref;
>  	struct v4l2_ctrl *ctrl, *next_ctrl;
>  	struct v4l2_subscribed_event *sev, *next_sev;
>  
> -	if (hdl == NULL || hdl->buckets == NULL)
> -		return;
> +	if (!hdl)
> +		return 0;
> +
> +	if (!hdl->buckets)
> +		return hdl->error;

!hdl->buckets means the handler has been freed, or is not initialized.
I'd return 0 in that case.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

>  
>  	v4l2_ctrl_handler_free_request(hdl);
>  
> @@ -1663,6 +1666,8 @@ void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl)
>  	hdl->cached = NULL;
>  	mutex_unlock(hdl->lock);
>  	mutex_destroy(&hdl->_lock);
> +
> +	return hdl->error;
>  }
>  EXPORT_SYMBOL(v4l2_ctrl_handler_free);
>  
> diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
> index 3a87096e064f..c32c46286441 100644
> --- a/include/media/v4l2-ctrls.h
> +++ b/include/media/v4l2-ctrls.h
> @@ -579,8 +579,10 @@ int v4l2_ctrl_handler_init_class(struct v4l2_ctrl_handler *hdl,
>   * @hdl:	The control handler.
>   *
>   * Does nothing if @hdl == NULL.
> + *
> + * Return: @hdl's error field or 0 if @hdl is NULL.
>   */
> -void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl);
> +int v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl);
>  
>  /**
>   * v4l2_ctrl_lock() - Helper function to lock the handler

-- 
Regards,

Laurent Pinchart