Re: [PATCH v5 4/9] userdiff: add and use for_each_userdiff_driver()

> +static int userdiff_find_by_namelen_cb(struct userdiff_driver *driver,
> +				       enum userdiff_driver_type type, void *priv)
>  {
> -	int i;
> -	for (i = 0; i < ndrivers; i++) {
> -		struct userdiff_driver *drv = drivers + i;
> -		if (!strncmp(drv->name, k, len) && !drv->name[len])
> -			return drv;
> -	}
> -	for (i = 0; i < ARRAY_SIZE(builtin_drivers); i++) {
> -		struct userdiff_driver *drv = builtin_drivers + i;
> -		if (!strncmp(drv->name, k, len) && !drv->name[len])
> -			return drv;
> +	struct find_by_namelen_data *cb_data = priv;
> +
> +	if (!strncmp(driver->name, cb_data->name, cb_data->len) &&
> +	    !driver->name[cb_data->len]) {
> +		cb_data->driver = driver;
> +		return 1; /* tell the caller to stop iterating */
>  	}
> -	return NULL;
> +	return 0;
> +}
> ...
> +enum userdiff_driver_type {
> +	USERDIFF_DRIVER_TYPE_BUILTIN = 1<<0,
> +	USERDIFF_DRIVER_TYPE_CUSTOM = 1<<1,
> +};
> +typedef int (*each_userdiff_driver_fn)(struct userdiff_driver *,
> +				       enum userdiff_driver_type, void *);