Subject: [PATCH net-next v7 06/11] net: ipv6: Use link netns in newlink() of rtnl_link_ops

From: Xiao Liang <[email-masked]>
Date: Sat, 4 Jan 2025 20:57:27 +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.

Set correct netns in priv before registering device, and avoid
overwriting it in ndo_init() path.

Signed-off-by: Xiao Liang <[email-masked]>
---
 net/ipv6/ip6_gre.c    | 22 ++++++++++++----------
 net/ipv6/ip6_tunnel.c | 13 ++++++++-----
 net/ipv6/ip6_vti.c    | 10 ++++++----
 net/ipv6/sit.c        | 11 +++++++----
 4 files changed, 33 insertions(+), 23 deletions(-)

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 3efd51f0d7d2..1d47c229068d 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);
 	strcpy(tunnel->parms.name, dev->name);
 
 	ret = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
@@ -1882,7 +1883,8 @@ static int ip6erspan_tap_init(struct net_device *dev)
 	tunnel = netdev_priv(dev);
 
 	tunnel->dev = dev;
-	tunnel->net = dev_net(dev);
+	if (!tunnel->net)
+		tunnel->net = dev_net(dev);
 	strcpy(tunnel->parms.name, dev->name);
 
 	ret = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
@@ -1971,7 +1973,7 @@ static bool ip6gre_netlink_encap_parms(struct nlattr *data[],
 	return ret;
 }
 
-static int ip6gre_newlink_common(struct net *src_net, struct net_device *dev,
+static int ip6gre_newlink_common(struct net *link_net, struct net_device *dev,
 				 struct nlattr *tb[], struct nlattr *data[],
 				 struct netlink_ext_ack *extack)
 {
@@ -1992,7 +1994,7 @@ static int ip6gre_newlink_common(struct net *src_net, struct net_device *dev,
 		eth_hw_addr_random(dev);
 
 	nt->dev = dev;
-	nt->net = dev_net(dev);
+	nt->net = link_net;
 
 	err = register_netdevice(dev);
 	if (err)
@@ -2010,13 +2012,13 @@ static int ip6gre_newlink(struct rtnl_newlink_params *params)
 	struct netlink_ext_ack *extack = params->extack;
 	struct net_device *dev = params->dev;
 	struct nlattr **data = params->data;
-	struct net *src_net = params->net;
 	struct nlattr **tb = params->tb;
-	struct net *net = dev_net(dev);
 	struct ip6gre_net *ign;
 	struct ip6_tnl *nt;
+	struct net *net;
 	int err;
 
+	net = params->link_net ? : dev_net(dev);
 	nt = netdev_priv(dev);
 	ip6gre_netlink_parms(data, &nt->parms);
 	ign = net_generic(net, ip6gre_net_id);
@@ -2029,7 +2031,7 @@ static int ip6gre_newlink(struct rtnl_newlink_params *params)
 			return -EEXIST;
 	}
 
-	err = ip6gre_newlink_common(src_net, dev, tb, data, extack);
+	err = ip6gre_newlink_common(net, dev, tb, data, extack);
 	if (!err) {
 		ip6gre_tnl_link_config(nt, !tb[IFLA_MTU]);
 		ip6gre_tunnel_link_md(ign, nt);
@@ -2250,13 +2252,13 @@ static int ip6erspan_newlink(struct rtnl_newlink_params *params)
 	struct netlink_ext_ack *extack = params->extack;
 	struct net_device *dev = params->dev;
 	struct nlattr **data = params->data;
-	struct net *src_net = params->net;
 	struct nlattr **tb = params->tb;
-	struct net *net = dev_net(dev);
 	struct ip6gre_net *ign;
 	struct ip6_tnl *nt;
+	struct net *net;
 	int err;
 
+	net = params->link_net ? : dev_net(dev);
 	nt = netdev_priv(dev);
 	ip6gre_netlink_parms(data, &nt->parms);
 	ip6erspan_set_version(data, &nt->parms);
@@ -2270,7 +2272,7 @@ static int ip6erspan_newlink(struct rtnl_newlink_params *params)
 			return -EEXIST;
 	}
 
-	err = ip6gre_newlink_common(src_net, dev, tb, data, extack);
+	err = ip6gre_newlink_common(net, dev, tb, data, extack);
 	if (!err) {
 		ip6erspan_tnl_link_config(nt, !tb[IFLA_MTU]);
 		ip6erspan_tunnel_link_md(ign, nt);
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index f4bdbabc3246..cb09cc878dee 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -253,8 +253,7 @@ static void ip6_dev_free(struct net_device *dev)
 static int ip6_tnl_create2(struct net_device *dev)
 {
 	struct ip6_tnl *t = netdev_priv(dev);
-	struct net *net = dev_net(dev);
-	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
+	struct ip6_tnl_net *ip6n = net_generic(t->net, ip6_tnl_net_id);
 	int err;
 
 	dev->rtnl_link_ops = &ip6_link_ops;
@@ -1878,7 +1877,8 @@ ip6_tnl_dev_init_gen(struct net_device *dev)
 	int t_hlen;
 
 	t->dev = dev;
-	t->net = dev_net(dev);
+	if (!t->net)
+		t->net = dev_net(dev);
 
 	ret = dst_cache_init(&t->dst_cache, GFP_KERNEL);
 	if (ret)
@@ -2007,13 +2007,16 @@ static int ip6_tnl_newlink(struct rtnl_newlink_params *params)
 	struct net_device *dev = params->dev;
 	struct nlattr **data = params->data;
 	struct nlattr **tb = params->tb;
-	struct net *net = dev_net(dev);
-	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
 	struct ip_tunnel_encap ipencap;
+	struct ip6_tnl_net *ip6n;
 	struct ip6_tnl *nt, *t;
+	struct net *net;
 	int err;
 
+	net = params->link_net ? : dev_net(dev);
+	ip6n = net_generic(net, ip6_tnl_net_id);
 	nt = netdev_priv(dev);
+	nt->net = net;
 
 	if (ip_tunnel_netlink_encap_parms(data, &ipencap)) {
 		err = ip6_tnl_encap_setup(nt, &ipencap);
diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c
index 79e601e629d2..a3108a7464c7 100644
--- a/net/ipv6/ip6_vti.c
+++ b/net/ipv6/ip6_vti.c
@@ -177,8 +177,7 @@ vti6_tnl_unlink(struct vti6_net *ip6n, struct ip6_tnl *t)
 static int vti6_tnl_create2(struct net_device *dev)
 {
 	struct ip6_tnl *t = netdev_priv(dev);
-	struct net *net = dev_net(dev);
-	struct vti6_net *ip6n = net_generic(net, vti6_net_id);
+	struct vti6_net *ip6n = net_generic(t->net, vti6_net_id);
 	int err;
 
 	dev->rtnl_link_ops = &vti6_link_ops;
@@ -925,7 +924,8 @@ static inline int vti6_dev_init_gen(struct net_device *dev)
 	struct ip6_tnl *t = netdev_priv(dev);
 
 	t->dev = dev;
-	t->net = dev_net(dev);
+	if (!t->net)
+		t->net = dev_net(dev);
 	netdev_hold(dev, &t->dev_tracker, GFP_KERNEL);
 	netdev_lockdep_set_classes(dev);
 	return 0;
@@ -1001,13 +1001,15 @@ static int vti6_newlink(struct rtnl_newlink_params *params)
 {
 	struct net_device *dev = params->dev;
 	struct nlattr **data = params->data;
-	struct net *net = dev_net(dev);
 	struct ip6_tnl *nt;
+	struct net *net;
 
+	net = params->link_net ? : dev_net(dev);
 	nt = netdev_priv(dev);
 	vti6_netlink_parms(data, &nt->parms);
 
 	nt->parms.proto = IPPROTO_IPV6;
+	nt->net = net;
 
 	if (vti6_locate(net, &nt->parms, 0))
 		return -EEXIST;
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 4dd1309d1eb3..8888fc51fa0b 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -201,8 +201,7 @@ static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
 static int ipip6_tunnel_create(struct net_device *dev)
 {
 	struct ip_tunnel *t = netdev_priv(dev);
-	struct net *net = dev_net(dev);
-	struct sit_net *sitn = net_generic(net, sit_net_id);
+	struct sit_net *sitn = net_generic(t->net, sit_net_id);
 	int err;
 
 	__dev_addr_set(dev, &t->parms.iph.saddr, 4);
@@ -270,6 +269,7 @@ static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
 	nt = netdev_priv(dev);
 
 	nt->parms = *parms;
+	nt->net = net;
 	if (ipip6_tunnel_create(dev) < 0)
 		goto failed_free;
 
@@ -1449,7 +1449,8 @@ static int ipip6_tunnel_init(struct net_device *dev)
 	int err;
 
 	tunnel->dev = dev;
-	tunnel->net = dev_net(dev);
+	if (!tunnel->net)
+		tunnel->net = dev_net(dev);
 	strcpy(tunnel->parms.name, dev->name);
 
 	ipip6_tunnel_bind_dev(dev);
@@ -1555,15 +1556,17 @@ static int ipip6_newlink(struct rtnl_newlink_params *params)
 	struct net_device *dev = params->dev;
 	struct nlattr **data = params->data;
 	struct nlattr **tb = params->tb;
-	struct net *net = dev_net(dev);
 	struct ip_tunnel *nt;
 	struct ip_tunnel_encap ipencap;
 #ifdef CONFIG_IPV6_SIT_6RD
 	struct ip_tunnel_6rd ip6rd;
 #endif
+	struct net *net;
 	int err;
 
+	net = params->link_net ? : dev_net(dev);
 	nt = netdev_priv(dev);
+	nt->net = net;
 
 	if (ip_tunnel_netlink_encap_parms(data, &ipencap)) {
 		err = ip_tunnel_encap_setup(nt, &ipencap);
-- 
2.47.1