Re: [PATCH net-next RFC v4 01/15] devlink: Add reload action option to devlink reload command

[Jakub Kicinski]

On Mon, 14 Sep 2020 09:07:48 +0300 Moshe Shemesh wrote:
> @@ -3011,12 +3060,41 @@ static int devlink_nl_cmd_reload(struct sk_buff *skb, struct genl_info *info)
>  			return PTR_ERR(dest_net);
>  	}
>  
> -	err = devlink_reload(devlink, dest_net, info->extack);
> +	if (info->attrs[DEVLINK_ATTR_RELOAD_ACTION])
> +		action = nla_get_u8(info->attrs[DEVLINK_ATTR_RELOAD_ACTION]);
> +	else
> +		action = DEVLINK_RELOAD_ACTION_DRIVER_REINIT;
> +
> +	if (action == DEVLINK_RELOAD_ACTION_UNSPEC || action > DEVLINK_RELOAD_ACTION_MAX) {
> +		NL_SET_ERR_MSG_MOD(info->extack, "Invalid reload action");
> +		return -EINVAL;
> +	} else if (!devlink_reload_action_is_supported(devlink, action)) {
> +		NL_SET_ERR_MSG_MOD(info->extack, "Requested reload action is not supported");
> +		return -EOPNOTSUPP;
> +	}
> +
> +	err = devlink_reload(devlink, dest_net, action, info->extack, &actions_performed);
>  
>  	if (dest_net)
>  		put_net(dest_net);
>  
> -	return err;
> +	if (err)
> +		return err;
> +
> +	WARN_ON(!actions_performed);
> +	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
> +	if (!msg)
> +		return -ENOMEM;
> +
> +	err = devlink_nl_reload_actions_performed_fill(msg, devlink, actions_performed,
> +						       DEVLINK_CMD_RELOAD, info->snd_portid,
> +						       info->snd_seq, 0);
> +	if (err) {
> +		nlmsg_free(msg);
> +		return err;
> +	}
> +
> +	return genlmsg_reply(msg, info);

I think generating the reply may break existing users. Only generate
the reply if request contained DEVLINK_ATTR_RELOAD_ACTION (or any other
new attribute which existing users can't pass).