On Thu, Feb 13, 2025 at 2:20 PM Kuniyuki Iwashima <kuniyu@xxxxxxxxxx> wrote:
>
> From: Xiao Liang <shaw.leon@xxxxxxxxx>
> Date: Mon, 10 Feb 2025 21:29:56 +0800
> > When link_net is set, use it as link netns instead of dev_net(). This
> > prepares for rtnetlink core to create device in target netns directly,
> > in which case the two namespaces may be different.
> >
> > Convert common ip_tunnel_newlink() to accept an extra link netns
> > argument. Don't overwrite ip_tunnel.net in ip_tunnel_init().
>
> Why... ? see a comment below.
>
>
> [...]
> > diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
> > index 1fe9b13d351c..26d15f907551 100644
> > --- a/net/ipv4/ip_gre.c
> > +++ b/net/ipv4/ip_gre.c
> > @@ -1413,7 +1413,8 @@ static int ipgre_newlink(struct net_device *dev,
> > err = ipgre_netlink_parms(dev, data, tb, &p, &fwmark);
> > if (err < 0)
> > return err;
> > - return ip_tunnel_newlink(dev, tb, &p, fwmark);
> > + return ip_tunnel_newlink(params->link_net ? : dev_net(dev), dev, tb, &p,
>
> This is duplicate at all call sites, let's move it into
> ip_tunnel_newlink() by passing params.
>
Existing tunnels use `params->link_net ? : dev_net(dev)` for
backward compatibility. But I think we can leave the choice of netns
to future tunnel drivers because rtnl_newlink_link_net() is preferred
in general.
>
> > + fwmark);
> > }
> >
> > static int erspan_newlink(struct net_device *dev,
> >
> >
> > diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
> > index 09b73acf037a..618a50d5c0c2 100644
> > --- a/net/ipv4/ip_tunnel.c
> > +++ b/net/ipv4/ip_tunnel.c
> > @@ -1213,11 +1213,11 @@ void ip_tunnel_delete_nets(struct list_head *net_list, unsigned int id,
> > }
> > EXPORT_SYMBOL_GPL(ip_tunnel_delete_nets);
> >
> > -int ip_tunnel_newlink(struct net_device *dev, struct nlattr *tb[],
> > - struct ip_tunnel_parm_kern *p, __u32 fwmark)
> > +int ip_tunnel_newlink(struct net *net, struct net_device *dev,
> > + struct nlattr *tb[], struct ip_tunnel_parm_kern *p,
> > + __u32 fwmark)
> > {
> > struct ip_tunnel *nt;
> > - struct net *net = dev_net(dev);
> > struct ip_tunnel_net *itn;
> > int mtu;
> > int err;
> > @@ -1326,7 +1326,9 @@ int ip_tunnel_init(struct net_device *dev)
> > }
> >
> > tunnel->dev = dev;
> > - tunnel->net = dev_net(dev);
> > + if (!tunnel->net)
> > + tunnel->net = dev_net(dev);
>
> Isn't tunnel->net always non-NULL ?
>
> ip_tunnel_newlink
> -> netdev_priv(dev)->net = net
> -> register_netdevice(dev)
> -> dev->netdev_ops->ndo_init(dev)
> -> ip_tunnel_init(dev)
> -> netdev_priv(dev)->net = dev_net(dev)
Didn't find a path that can leave tunnel->net to NULL either.
I think we can remove this.
Thanks.
