From: Xiao Liang <shaw.leon@xxxxxxxxx> Date: Fri, 14 Feb 2025 17:22:28 +0800 > On Thu, Feb 13, 2025 at 7:00 PM Kuniyuki Iwashima <kuniyu@xxxxxxxxxx> wrote: > > > > From: Xiao Liang <shaw.leon@xxxxxxxxx> > > Date: Thu, 13 Feb 2025 17:55:32 +0800 > > > On Thu, Feb 13, 2025 at 4:37 PM Xiao Liang <shaw.leon@xxxxxxxxx> wrote: > > > > > > > > On Thu, Feb 13, 2025 at 3:05 PM Kuniyuki Iwashima <kuniyu@xxxxxxxxxx> wrote: > > > > > > > > > [...] > > > > > > diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c > > > > > > index 863852abe8ea..108600dc716f 100644 > > > > > > --- a/net/ipv6/ip6_gre.c > > > > > > +++ b/net/ipv6/ip6_gre.c > > > > > > @@ -1498,7 +1498,8 @@ static int ip6gre_tunnel_init_common(struct net_device *dev) > > > > > > tunnel = netdev_priv(dev); > > > > > > > > > > > > tunnel->dev = dev; > > > > > > - tunnel->net = dev_net(dev); > > > > > > + if (!tunnel->net) > > > > > > + tunnel->net = dev_net(dev); > > > > > > > > > > Same question as patch 5 for here and other parts. > > > > > Do we need this check and assignment ? > > > > > > > > > > ip6gre_newlink_common > > > > > -> nt->net = dev_net(dev) > > > > > -> register_netdevice > > > > > -> ndo_init / ip6gre_tunnel_init() > > > > > -> ip6gre_tunnel_init_common > > > > > -> tunnel->net = dev_net(dev) > > > > > > > > Will remove this line. > > > > > > However, fb tunnel of ip6_tunnel, ip6_vti and sit can have > > > tunnel->net == NULL here. Take ip6_tunnel for example: > > > > > > ip6_tnl_init_net() > > > -> ip6_fb_tnl_dev_init() > > > -> register_netdev() > > > -> register_netdevice() > > > -> ip6_tnl_dev_init() > > > > > > This code path (including ip6_fb_tnl_dev_init()) doesn't set > > > tunnel->net. But for ip6_gre, ip6gre_fb_tunnel_init() does. > > > > Ah, okay. Then, let's set net in a single place, which would > > be better than spreading net assignment and adding null check > > in ->ndo_init(), and maybe apply the same to IPv4 tunnels ? > > Tunnels are created in three ways: a) rtnetlink newlink, > b) ioctl SIOCADDTUNNEL and c) during per netns init (fb). > The code paths don't have much in common, and refactoring > to set net in a single place is somewhat beyond the scope > of this series. But for now I think we could put a general rule: > net should be set prior to register_netdevice(). > > For IPv4 tunnels, tunnel->net of a) is set in ip_tunnel_newlink(). > b) and c) are set in __ip_tunnel_create(): > ip_tunnel_init_net() -> __ip_tunnel_create() > ip_tunnel_ctl() -> ip_tunnel_create() -> __ip_tunnel_create() > So net has already been initialized when register_netdevice() > is called. > > But it varies for IPv6 tunnels. Some set net for a) or c) while > some don't. This patch has "fixed" for a). As for c) we can > adopt the way of ip6_gre - setting net in *_fb_tunnel_init(), > then remove the check in ndo_init(). > > Is it reasonable? Yes, fair enough.
