Subject: Re: [PATCHv3 net-next] rtnetlink: Honour NLM_F_ECHO flag in rtnl_{new, set, del}link

From: Jakub Kicinski <[email-masked]>
Date: Tue, 27 Sep 2022 07:21:30 -0700

On Tue, 27 Sep 2022 12:13:03 +0800 Hangbin Liu wrote:
> @@ -3382,6 +3401,12 @@ static int rtnl_newlink_create(struct sk_buff *skb, struct ifinfomsg *ifm,
>  		if (err)
>  			goto out_unregister;
>  	}
> +
> +	nskb = rtmsg_ifinfo_build_skb(RTM_NEWLINK, dev, 0, 0, GFP_KERNEL, NULL,
> +				      0, pid, nlh->nlmsg_seq);
> +	if (nskb)
> +		rtnl_notify(nskb, dev_net(dev), pid, RTNLGRP_LINK, nlh, GFP_KERNEL);
> +
>  out:
>  	if (link_net)
>  		put_net(link_net);

I'm surprised you're adding new notifications. Does the kernel not
already notify about new links? I thought rtnl_newlink_create() ->
rtnl_configure_link() -> __dev_notify_flags() sends a notification,
already.