[PATCH v3 4/9] media: platform: microchip: use for_each_endpoint_of_node()

[Dan Carpenter]

On Thu, May 30, 2024 at 02:06:05AM +0000, Kuninori Morimoto wrote:
> diff --git a/drivers/media/platform/microchip/microchip-sama5d2-isc.c b/drivers/media/platform/microchip/microchip-sama5d2-isc.c
> index 5ac149cf3647f..60b6d922d764e 100644
> --- a/drivers/media/platform/microchip/microchip-sama5d2-isc.c
> +++ b/drivers/media/platform/microchip/microchip-sama5d2-isc.c
> @@ -353,33 +353,29 @@ static const u32 isc_sama5d2_gamma_table[][GAMMA_ENTRIES] = {
>  static int isc_parse_dt(struct device *dev, struct isc_device *isc)
>  {
>  	struct device_node *np = dev->of_node;
> -	struct device_node *epn = NULL;
> +	struct device_node *epn;
>  	struct isc_subdev_entity *subdev_entity;
>  	unsigned int flags;
> -	int ret;
>  
>  	INIT_LIST_HEAD(&isc->subdev_entities);
>  
> -	while (1) {
> +	for_each_endpoint_of_node(np, epn) {
>  		struct v4l2_fwnode_endpoint v4l2_epn = { .bus_type = 0 };
> -
> -		epn = of_graph_get_next_endpoint(np, epn);
> -		if (!epn)
> -			return 0;
> +		int ret;
>  
>  		ret = v4l2_fwnode_endpoint_parse(of_fwnode_handle(epn),
>  						 &v4l2_epn);
>  		if (ret) {
> -			ret = -EINVAL;
> +			of_node_put(epn);
>  			dev_err(dev, "Could not parse the endpoint\n");
> -			break;
> +			return -EINVAL;
>  		}
>  
>  		subdev_entity = devm_kzalloc(dev, sizeof(*subdev_entity),
>  					     GFP_KERNEL);
>  		if (!subdev_entity) {
> -			ret = -ENOMEM;
> -			break;
> +			of_node_put(epn);
> +			return -ENOMEM;
>  		}
>  		subdev_entity->epn = epn;

This code is an example of what Laurent was talking about.  We're taking
storing "subdev_entity->epn = epn" but then not incrementing the
refcount.  Perhaps it's not necessary?

The difference between this and _scoped() would be if we stored epn and
then returned.  I feel like that's less common.  We could detect that
sort of thing using static analysis if it turned out to be an issue.

regards,
dan carpenter