Merge: net: Fix deadlock on netns change.

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-10/-/merge_requests/2576

JIRA: https://redhat.atlassian.net/browse/RHEL-144808
Upstream Status: linux.git

Backport upstream commit 7ca486d08a30 ("rtnetlink: Create link directly in
target net namespace") and its dependencies, plus selftests.

Signed-off-by: Guillaume Nault <gnault@redhat.com>

Approved-by: Antoine Tenart <atenart@redhat.com>
Approved-by: José Ignacio Tornos Martínez <jtornosm@redhat.com>

Merged-by: CKI GitLab Kmaint Pipeline Bot <26919896-cki-kmaint-pipeline-bot@users.noreply.gitlab.com>

drivers/infiniband/ulp/ipoib/ipoib_netlink.c

@@ -97,10 +97,13 @@ out_err:
 	return ret;
 }
 
-static int ipoib_new_child_link(struct net *src_net, struct net_device *dev,
-				struct nlattr *tb[], struct nlattr *data[],
+static int ipoib_new_child_link(struct net_device *dev,
+				struct rtnl_newlink_params *params,
 				struct netlink_ext_ack *extack)
 {
+	struct net *link_net = rtnl_newlink_link_net(params);
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	struct net_device *pdev;
 	struct ipoib_dev_priv *ppriv;
 	u16 child_pkey;
@@ -109,7 +112,7 @@ static int ipoib_new_child_link(struct net *src_net, struct net_device *dev,
 	if (!tb[IFLA_LINK])
 		return -EINVAL;
 
-	pdev = __dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
+	pdev = __dev_get_by_index(link_net, nla_get_u32(tb[IFLA_LINK]));
 	if (!pdev || pdev->type != ARPHRD_INFINIBAND)
 		return -ENODEV;
 

drivers/net/amt.c

@@ -3161,14 +3161,17 @@ static int amt_validate(struct nlattr *tb[], struct nlattr *data[],
 	return 0;
 }
 
-static int amt_newlink(struct net *net, struct net_device *dev,
-		       struct nlattr *tb[], struct nlattr *data[],
+static int amt_newlink(struct net_device *dev,
+		       struct rtnl_newlink_params *params,
 		       struct netlink_ext_ack *extack)
 {
+	struct net *link_net = rtnl_newlink_link_net(params);
 	struct amt_dev *amt = netdev_priv(dev);
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	int err = -EINVAL;
 
-	amt->net = net;
+	amt->net = link_net;
 	amt->mode = nla_get_u32(data[IFLA_AMT_MODE]);
 
 	if (data[IFLA_AMT_MAX_TUNNELS] &&
@@ -3183,7 +3186,7 @@ static int amt_newlink(struct net *net, struct net_device *dev,
 	amt->hash_buckets = AMT_HSIZE;
 	amt->nr_tunnels = 0;
 	get_random_bytes(&amt->hash_seed, sizeof(amt->hash_seed));
-	amt->stream_dev = dev_get_by_index(net,
+	amt->stream_dev = dev_get_by_index(link_net,
 					   nla_get_u32(data[IFLA_AMT_LINK]));
 	if (!amt->stream_dev) {
 		NL_SET_ERR_MSG_ATTR(extack, tb[IFLA_AMT_LINK],

drivers/net/bareudp.c

@@ -698,10 +698,13 @@ static void bareudp_dellink(struct net_device *dev, struct list_head *head)
 	unregister_netdevice_queue(dev, head);
 }
 
-static int bareudp_newlink(struct net *net, struct net_device *dev,
-			   struct nlattr *tb[], struct nlattr *data[],
+static int bareudp_newlink(struct net_device *dev,
+			   struct rtnl_newlink_params *params,
 			   struct netlink_ext_ack *extack)
 {
+	struct net *link_net = rtnl_newlink_link_net(params);
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	struct bareudp_conf conf;
 	int err;
 
@@ -709,7 +712,7 @@ static int bareudp_newlink(struct net *net, struct net_device *dev,
 	if (err)
 		return err;
 
-	err = bareudp_configure(net, dev, &conf, extack);
+	err = bareudp_configure(link_net, dev, &conf, extack);
 	if (err)
 		return err;
 

drivers/net/bonding/bond_netlink.c

@@ -591,10 +591,12 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[],
 	return 0;
 }
 
-static int bond_newlink(struct net *src_net, struct net_device *bond_dev,
-			struct nlattr *tb[], struct nlattr *data[],
+static int bond_newlink(struct net_device *bond_dev,
+			struct rtnl_newlink_params *params,
 			struct netlink_ext_ack *extack)
 {
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	int err;
 
 	err = bond_changelink(bond_dev, tb, data, extack);

drivers/net/can/dev/netlink.c

@@ -624,8 +624,8 @@ nla_put_failure:
 	return -EMSGSIZE;
 }
 
-static int can_newlink(struct net *src_net, struct net_device *dev,
-		       struct nlattr *tb[], struct nlattr *data[],
+static int can_newlink(struct net_device *dev,
+		       struct rtnl_newlink_params *params,
 		       struct netlink_ext_ack *extack)
 {
 	return -EOPNOTSUPP;

drivers/net/can/vxcan.c

@@ -172,10 +172,13 @@ static void vxcan_setup(struct net_device *dev)
 /* forward declaration for rtnl_create_link() */
 static struct rtnl_link_ops vxcan_link_ops;
 
-static int vxcan_newlink(struct net *peer_net, struct net_device *dev,
-			 struct nlattr *tb[], struct nlattr *data[],
+static int vxcan_newlink(struct net_device *dev,
+			 struct rtnl_newlink_params *params,
 			 struct netlink_ext_ack *extack)
 {
+	struct net *peer_net = rtnl_newlink_peer_net(params);
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	struct vxcan_priv *priv;
 	struct net_device *peer;
 

drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c

@@ -117,11 +117,14 @@ static void rmnet_unregister_bridge(struct rmnet_port *port)
 	rmnet_unregister_real_device(bridge_dev);
 }
 
-static int rmnet_newlink(struct net *src_net, struct net_device *dev,
-			 struct nlattr *tb[], struct nlattr *data[],
+static int rmnet_newlink(struct net_device *dev,
+			 struct rtnl_newlink_params *params,
 			 struct netlink_ext_ack *extack)
 {
+	struct net *link_net = rtnl_newlink_link_net(params);
 	u32 data_format = RMNET_FLAGS_INGRESS_DEAGGREGATION;
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	struct net_device *real_dev;
 	int mode = RMNET_EPMODE_VND;
 	struct rmnet_endpoint *ep;
@@ -134,7 +137,7 @@ static int rmnet_newlink(struct net *src_net, struct net_device *dev,
 		return -EINVAL;
 	}
 
-	real_dev = __dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
+	real_dev = __dev_get_by_index(link_net, nla_get_u32(tb[IFLA_LINK]));
 	if (!real_dev) {
 		NL_SET_ERR_MSG_MOD(extack, "link does not exist");
 		return -ENODEV;

drivers/net/geneve.c

@@ -2132,10 +2132,13 @@ static void geneve_link_config(struct net_device *dev,
 	geneve_change_mtu(dev, ldev_mtu - info->options_len);
 }
 
-static int geneve_newlink(struct net *net, struct net_device *dev,
-			  struct nlattr *tb[], struct nlattr *data[],
+static int geneve_newlink(struct net_device *dev,
+			  struct rtnl_newlink_params *params,
 			  struct netlink_ext_ack *extack)
 {
+	struct net *link_net = rtnl_newlink_link_net(params);
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	struct geneve_config cfg = {
 		.df = GENEVE_DF_UNSET,
 		.use_udp6_rx_checksums = false,
@@ -2151,7 +2154,7 @@ static int geneve_newlink(struct net *net, struct net_device *dev,
 	if (err)
 		return err;
 
-	err = geneve_configure(net, dev, extack, &cfg);
+	err = geneve_configure(link_net, dev, extack, &cfg);
 	if (err)
 		return err;
 

drivers/net/gtp.c

@@ -1460,10 +1460,12 @@ static int gtp_create_sockets(struct gtp_dev *gtp, const struct nlattr *nla,
 #define GTP_TH_MAXLEN	(sizeof(struct udphdr) + sizeof(struct gtp0_header))
 #define GTP_IPV6_MAXLEN	(sizeof(struct ipv6hdr) + GTP_TH_MAXLEN)
 
-static int gtp_newlink(struct net *src_net, struct net_device *dev,
-		       struct nlattr *tb[], struct nlattr *data[],
+static int gtp_newlink(struct net_device *dev,
+		       struct rtnl_newlink_params *params,
 		       struct netlink_ext_ack *extack)
 {
+	struct net *link_net = rtnl_newlink_link_net(params);
+	struct nlattr **data = params->data;
 	unsigned int role = GTP_ROLE_GGSN;
 	struct gtp_dev *gtp;
 	struct gtp_net *gn;
@@ -1496,7 +1498,7 @@ static int gtp_newlink(struct net *src_net, struct net_device *dev,
 	else
 		gtp->restart_count = nla_get_u8(data[IFLA_GTP_RESTART_COUNT]);
 
-	gtp->net = src_net;
+	gtp->net = link_net;
 
 	err = gtp_hashtable_new(gtp, hashsize);
 	if (err < 0)
@@ -1526,7 +1528,7 @@ static int gtp_newlink(struct net *src_net, struct net_device *dev,
 		goto out_encap;
 	}
 
-	gn = net_generic(dev_net(dev), gtp_net_id);
+	gn = net_generic(link_net, gtp_net_id);
 	list_add_rcu(&gtp->list, &gn->gtp_dev_list);
 	dev->priv_destructor = gtp_destructor;
 

drivers/net/ipvlan/ipvlan.h

@@ -166,8 +166,7 @@ struct ipvl_addr *ipvlan_addr_lookup(struct ipvl_port *port, void *lyr3h,
 void *ipvlan_get_L3_hdr(struct ipvl_port *port, struct sk_buff *skb, int *type);
 void ipvlan_count_rx(const struct ipvl_dev *ipvlan,
 		     unsigned int len, bool success, bool mcast);
-int ipvlan_link_new(struct net *src_net, struct net_device *dev,
-		    struct nlattr *tb[], struct nlattr *data[],
+int ipvlan_link_new(struct net_device *dev, struct rtnl_newlink_params *params,
 		    struct netlink_ext_ack *extack);
 void ipvlan_link_delete(struct net_device *dev, struct list_head *head);
 void ipvlan_link_setup(struct net_device *dev);

drivers/net/ipvlan/ipvlan_main.c

@@ -533,11 +533,13 @@ err:
 	return ret;
 }
 
-int ipvlan_link_new(struct net *src_net, struct net_device *dev,
-		    struct nlattr *tb[], struct nlattr *data[],
+int ipvlan_link_new(struct net_device *dev, struct rtnl_newlink_params *params,
 		    struct netlink_ext_ack *extack)
 {
+	struct net *link_net = rtnl_newlink_link_net(params);
 	struct ipvl_dev *ipvlan = netdev_priv(dev);
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	struct ipvl_port *port;
 	struct net_device *phy_dev;
 	int err;
@@ -546,7 +548,7 @@ int ipvlan_link_new(struct net *src_net, struct net_device *dev,
 	if (!tb[IFLA_LINK])
 		return -EINVAL;
 
-	phy_dev = __dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
+	phy_dev = __dev_get_by_index(link_net, nla_get_u32(tb[IFLA_LINK]));
 	if (!phy_dev)
 		return -ENODEV;
 

drivers/net/ipvlan/ipvtap.c

@@ -73,8 +73,8 @@ static void ipvtap_update_features(struct tap_dev *tap,
 	netdev_update_features(vlan->dev);
 }
 
-static int ipvtap_newlink(struct net *src_net, struct net_device *dev,
-			  struct nlattr *tb[], struct nlattr *data[],
+static int ipvtap_newlink(struct net_device *dev,
+			  struct rtnl_newlink_params *params,
 			  struct netlink_ext_ack *extack)
 {
 	struct ipvtap_dev *vlantap = netdev_priv(dev);
@@ -97,7 +97,7 @@ static int ipvtap_newlink(struct net *src_net, struct net_device *dev,
 	/* Don't put anything that may fail after macvlan_common_newlink
 	 * because we can't undo what it does.
 	 */
-	err =  ipvlan_link_new(src_net, dev, tb, data, extack);
+	err = ipvlan_link_new(dev, params, extack);
 	if (err) {
 		netdev_rx_handler_unregister(dev);
 		return err;

drivers/net/macsec.c

@@ -4170,11 +4170,14 @@ static int macsec_add_dev(struct net_device *dev, sci_t sci, u8 icv_len)
 
 static struct lock_class_key macsec_netdev_addr_lock_key;
 
-static int macsec_newlink(struct net *net, struct net_device *dev,
-			  struct nlattr *tb[], struct nlattr *data[],
+static int macsec_newlink(struct net_device *dev,
+			  struct rtnl_newlink_params *params,
 			  struct netlink_ext_ack *extack)
 {
+	struct net *link_net = rtnl_newlink_link_net(params);
 	struct macsec_dev *macsec = macsec_priv(dev);
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	rx_handler_func_t *rx_handler;
 	u8 icv_len = MACSEC_DEFAULT_ICV_LEN;
 	struct net_device *real_dev;
@@ -4183,7 +4186,7 @@ static int macsec_newlink(struct net *net, struct net_device *dev,
 
 	if (!tb[IFLA_LINK])
 		return -EINVAL;
-	real_dev = __dev_get_by_index(net, nla_get_u32(tb[IFLA_LINK]));
+	real_dev = __dev_get_by_index(link_net, nla_get_u32(tb[IFLA_LINK]));
 	if (!real_dev)
 		return -ENODEV;
 	if (real_dev->type != ARPHRD_ETHER)

drivers/net/macvlan.c

@@ -1447,21 +1447,24 @@ static int macvlan_changelink_sources(struct macvlan_dev *vlan, u32 mode,
 	return 0;
 }
 
-int macvlan_common_newlink(struct net *src_net, struct net_device *dev,
-			   struct nlattr *tb[], struct nlattr *data[],
+int macvlan_common_newlink(struct net_device *dev,
+			   struct rtnl_newlink_params *params,
 			   struct netlink_ext_ack *extack)
 {
+	struct net *link_net = rtnl_newlink_link_net(params);
 	struct macvlan_dev *vlan = netdev_priv(dev);
-	struct macvlan_port *port;
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	struct net_device *lowerdev;
-	int err;
-	int macmode;
+	struct macvlan_port *port;
 	bool create = false;
+	int macmode;
+	int err;
 
 	if (!tb[IFLA_LINK])
 		return -EINVAL;
 
-	lowerdev = __dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
+	lowerdev = __dev_get_by_index(link_net, nla_get_u32(tb[IFLA_LINK]));
 	if (lowerdev == NULL)
 		return -ENODEV;
 
@@ -1578,11 +1581,11 @@ destroy_macvlan_port:
 }
 EXPORT_SYMBOL_GPL(macvlan_common_newlink);
 
-static int macvlan_newlink(struct net *src_net, struct net_device *dev,
-			   struct nlattr *tb[], struct nlattr *data[],
+static int macvlan_newlink(struct net_device *dev,
+			   struct rtnl_newlink_params *params,
 			   struct netlink_ext_ack *extack)
 {
-	return macvlan_common_newlink(src_net, dev, tb, data, extack);
+	return macvlan_common_newlink(dev, params, extack);
 }
 
 void macvlan_dellink(struct net_device *dev, struct list_head *head)

drivers/net/macvtap.c

@@ -77,8 +77,8 @@ static void macvtap_update_features(struct tap_dev *tap,
 	netdev_update_features(vlan->dev);
 }
 
-static int macvtap_newlink(struct net *src_net, struct net_device *dev,
-			   struct nlattr *tb[], struct nlattr *data[],
+static int macvtap_newlink(struct net_device *dev,
+			   struct rtnl_newlink_params *params,
 			   struct netlink_ext_ack *extack)
 {
 	struct macvtap_dev *vlantap = netdev_priv(dev);
@@ -105,7 +105,7 @@ static int macvtap_newlink(struct net *src_net, struct net_device *dev,
 	/* Don't put anything that may fail after macvlan_common_newlink
 	 * because we can't undo what it does.
 	 */
-	err = macvlan_common_newlink(src_net, dev, tb, data, extack);
+	err = macvlan_common_newlink(dev, params, extack);
 	if (err) {
 		netdev_rx_handler_unregister(dev);
 		return err;

drivers/net/netkit.c

@@ -328,21 +328,25 @@ static int netkit_validate(struct nlattr *tb[], struct nlattr *data[],
 
 static struct rtnl_link_ops netkit_link_ops;
 
-static int netkit_new_link(struct net *peer_net, struct net_device *dev,
-			   struct nlattr *tb[], struct nlattr *data[],
+static int netkit_new_link(struct net_device *dev,
+			   struct rtnl_newlink_params *params,
 			   struct netlink_ext_ack *extack)
 {
-	struct nlattr *peer_tb[IFLA_MAX + 1], **tbp = tb, *attr;
+	struct net *peer_net = rtnl_newlink_peer_net(params);
+	struct nlattr *peer_tb[IFLA_MAX + 1], **tbp, *attr;
 	enum netkit_action default_prim = NETKIT_PASS;
 	enum netkit_action default_peer = NETKIT_PASS;
+	struct nlattr **data = params->data;
 	enum netkit_mode mode = NETKIT_L3;
 	unsigned char ifname_assign_type;
+	struct nlattr **tb = params->tb;
 	struct ifinfomsg *ifmp = NULL;
 	struct net_device *peer;
 	char ifname[IFNAMSIZ];
 	struct netkit *nk;
 	int err;
 
+	tbp = tb;
 	if (data) {
 		if (data[IFLA_NETKIT_MODE]) {
 			attr = data[IFLA_NETKIT_MODE];

drivers/net/pfcp.c

@@ -184,15 +184,16 @@ static int pfcp_add_sock(struct pfcp_dev *pfcp)
 	return PTR_ERR_OR_ZERO(pfcp->sock);
 }
 
-static int pfcp_newlink(struct net *net, struct net_device *dev,
-			struct nlattr *tb[], struct nlattr *data[],
+static int pfcp_newlink(struct net_device *dev,
+			struct rtnl_newlink_params *params,
 			struct netlink_ext_ack *extack)
 {
+	struct net *link_net = rtnl_newlink_link_net(params);
 	struct pfcp_dev *pfcp = netdev_priv(dev);
 	struct pfcp_net *pn;
 	int err;
 
-	pfcp->net = net;
+	pfcp->net = link_net;
 
 	err = pfcp_add_sock(pfcp);
 	if (err) {
@@ -206,7 +207,7 @@ static int pfcp_newlink(struct net *net, struct net_device *dev,
 		goto exit_del_pfcp_sock;
 	}
 
-	pn = net_generic(dev_net(dev), pfcp_net_id);
+	pn = net_generic(link_net, pfcp_net_id);
 	list_add_rcu(&pfcp->list, &pn->pfcp_dev_list);
 
 	netdev_dbg(dev, "registered new PFCP interface\n");

drivers/net/ppp/ppp_generic.c

@@ -1316,10 +1316,13 @@ static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
 	return 0;
 }
 
-static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
-			  struct nlattr *tb[], struct nlattr *data[],
+static int ppp_nl_newlink(struct net_device *dev,
+			  struct rtnl_newlink_params *params,
 			  struct netlink_ext_ack *extack)
 {
+	struct net *link_net = rtnl_newlink_link_net(params);
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	struct ppp_config conf = {
 		.unit = -1,
 		.ifname_is_set = true,
@@ -1356,7 +1359,7 @@ static int ppp_nl_newlink(struct net *src_net, struct net_device *dev,
 	if (!tb[IFLA_IFNAME] || !nla_len(tb[IFLA_IFNAME]) || !*(char *)nla_data(tb[IFLA_IFNAME]))
 		conf.ifname_is_set = false;
 
-	err = ppp_dev_configure(src_net, dev, &conf);
+	err = ppp_dev_configure(link_net, dev, &conf);
 
 out_unlock:
 	mutex_unlock(&ppp_mutex);

drivers/net/team/team_core.c

@@ -2189,10 +2189,12 @@ static void team_setup(struct net_device *dev)
 	dev->features |= NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_STAG_TX;
 }
 
-static int team_newlink(struct net *src_net, struct net_device *dev,
-			struct nlattr *tb[], struct nlattr *data[],
+static int team_newlink(struct net_device *dev,
+			struct rtnl_newlink_params *params,
 			struct netlink_ext_ack *extack)
 {
+	struct nlattr **tb = params->tb;
+
 	if (tb[IFLA_ADDRESS] == NULL)
 		eth_hw_addr_random(dev);
 

drivers/net/veth.c

@@ -1766,10 +1766,13 @@ static int veth_init_queues(struct net_device *dev, struct nlattr *tb[])
 	return 0;
 }
 
-static int veth_newlink(struct net *peer_net, struct net_device *dev,
-			struct nlattr *tb[], struct nlattr *data[],
+static int veth_newlink(struct net_device *dev,
+			struct rtnl_newlink_params *params,
 			struct netlink_ext_ack *extack)
 {
+	struct net *peer_net = rtnl_newlink_peer_net(params);
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	int err;
 	struct net_device *peer;
 	struct veth_priv *priv;

drivers/net/vrf.c

@@ -1699,11 +1699,12 @@ static void vrf_dellink(struct net_device *dev, struct list_head *head)
 	unregister_netdevice_queue(dev, head);
 }
 
-static int vrf_newlink(struct net *src_net, struct net_device *dev,
-		       struct nlattr *tb[], struct nlattr *data[],
+static int vrf_newlink(struct net_device *dev,
+		       struct rtnl_newlink_params *params,
 		       struct netlink_ext_ack *extack)
 {
 	struct net_vrf *vrf = netdev_priv(dev);
+	struct nlattr **data = params->data;
 	struct netns_vrf *nn_vrf;
 	bool *add_fib_rules;
 	struct net *net;

drivers/net/vxlan/vxlan_core.c

@@ -4390,10 +4390,13 @@ static int vxlan_nl2conf(struct nlattr *tb[], struct nlattr *data[],
 	return 0;
 }
 
-static int vxlan_newlink(struct net *src_net, struct net_device *dev,
-			 struct nlattr *tb[], struct nlattr *data[],
+static int vxlan_newlink(struct net_device *dev,
+			 struct rtnl_newlink_params *params,
 			 struct netlink_ext_ack *extack)
 {
+	struct net *link_net = rtnl_newlink_link_net(params);
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	struct vxlan_config conf;
 	int err;
 
@@ -4401,7 +4404,7 @@ static int vxlan_newlink(struct net *src_net, struct net_device *dev,
 	if (err)
 		return err;
 
-	return __vxlan_dev_create(src_net, dev, &conf, extack);
+	return __vxlan_dev_create(link_net, dev, &conf, extack);
 }
 
 static int vxlan_changelink(struct net_device *dev, struct nlattr *tb[],

drivers/net/wireguard/device.c

@@ -307,14 +307,15 @@ static void wg_setup(struct net_device *dev)
 	wg->dev = dev;
 }
 
-static int wg_newlink(struct net *src_net, struct net_device *dev,
-		      struct nlattr *tb[], struct nlattr *data[],
+static int wg_newlink(struct net_device *dev,
+		      struct rtnl_newlink_params *params,
 		      struct netlink_ext_ack *extack)
 {
+	struct net *link_net = rtnl_newlink_link_net(params);
 	struct wg_device *wg = netdev_priv(dev);
 	int ret = -ENOMEM;
 
-	rcu_assign_pointer(wg->creating_net, src_net);
+	rcu_assign_pointer(wg->creating_net, link_net);
 	init_rwsem(&wg->static_identity.lock);
 	mutex_init(&wg->socket_update_lock);
 	mutex_init(&wg->device_update_lock);

drivers/net/wireless/virtual/virt_wifi.c

@@ -523,11 +523,13 @@ static rx_handler_result_t virt_wifi_rx_handler(struct sk_buff **pskb)
 }
 
 /* Called with rtnl lock held. */
-static int virt_wifi_newlink(struct net *src_net, struct net_device *dev,
-			     struct nlattr *tb[], struct nlattr *data[],
+static int virt_wifi_newlink(struct net_device *dev,
+			     struct rtnl_newlink_params *params,
 			     struct netlink_ext_ack *extack)
 {
 	struct virt_wifi_netdev_priv *priv = netdev_priv(dev);
+	struct net *link_net = rtnl_newlink_link_net(params);
+	struct nlattr **tb = params->tb;
 	int err;
 
 	if (!tb[IFLA_LINK])
@@ -536,7 +538,7 @@ static int virt_wifi_newlink(struct net *src_net, struct net_device *dev,
 	netif_carrier_off(dev);
 
 	priv->upperdev = dev;
-	priv->lowerdev = __dev_get_by_index(src_net,
+	priv->lowerdev = __dev_get_by_index(link_net,
 					    nla_get_u32(tb[IFLA_LINK]));
 
 	if (!priv->lowerdev)

drivers/net/wwan/wwan_core.c

@@ -967,15 +967,18 @@ out:
 	return dev;
 }
 
-static int wwan_rtnl_newlink(struct net *src_net, struct net_device *dev,
-			     struct nlattr *tb[], struct nlattr *data[],
+static int wwan_rtnl_newlink(struct net_device *dev,
+			     struct rtnl_newlink_params *params,
 			     struct netlink_ext_ack *extack)
 {
 	struct wwan_device *wwandev = wwan_dev_get_by_parent(dev->dev.parent);
-	u32 link_id = nla_get_u32(data[IFLA_WWAN_LINK_ID]);
 	struct wwan_netdev_priv *priv = netdev_priv(dev);
+	struct nlattr **data = params->data;
+	u32 link_id;
 	int ret;
 
+	link_id = nla_get_u32(data[IFLA_WWAN_LINK_ID]);
+
 	if (IS_ERR(wwandev))
 		return PTR_ERR(wwandev);
 
@@ -1061,6 +1064,11 @@ static void wwan_create_default_link(struct wwan_device *wwandev,
 {
 	struct nlattr *tb[IFLA_MAX + 1], *linkinfo[IFLA_INFO_MAX + 1];
 	struct nlattr *data[IFLA_WWAN_MAX + 1];
+	struct rtnl_newlink_params params = {
+		.src_net = &init_net,
+		.tb = tb,
+		.data = data,
+	};
 	struct net_device *dev;
 	struct nlmsghdr *nlh;
 	struct sk_buff *msg;
@@ -1105,7 +1113,7 @@ static void wwan_create_default_link(struct wwan_device *wwandev,
 	if (WARN_ON(IS_ERR(dev)))
 		goto unlock;
 
-	if (WARN_ON(wwan_rtnl_newlink(&init_net, dev, tb, data, NULL))) {
+	if (WARN_ON(wwan_rtnl_newlink(dev, &params, NULL))) {
 		free_netdev(dev);
 		goto unlock;
 	}

include/linux/if_macvlan.h

@@ -59,8 +59,10 @@ static inline void macvlan_count_rx(const struct macvlan_dev *vlan,
 
 extern void macvlan_common_setup(struct net_device *dev);
 
-extern int macvlan_common_newlink(struct net *src_net, struct net_device *dev,
-				  struct nlattr *tb[], struct nlattr *data[],
+struct rtnl_newlink_params;
+
+extern int macvlan_common_newlink(struct net_device *dev,
+				  struct rtnl_newlink_params *params,
 				  struct netlink_ext_ack *extack);
 
 extern void macvlan_dellink(struct net_device *dev, struct list_head *head);

include/net/ip_tunnels.h

@@ -417,8 +417,9 @@ int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff *skb,
 		  bool log_ecn_error);
 int ip_tunnel_changelink(struct net_device *dev, struct nlattr *tb[],
 			 struct ip_tunnel_parm_kern *p, __u32 fwmark);
-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);
 void ip_tunnel_setup(struct net_device *dev, unsigned int net_id);
 
 bool ip_tunnel_netlink_encap_parms(struct nlattr *data[],

include/net/rtnetlink.h

@@ -69,6 +69,40 @@ static inline int rtnl_msg_family(const struct nlmsghdr *nlh)
 		return AF_UNSPEC;
 }
 
+/**
+ * struct rtnl_newlink_params - parameters of rtnl_link_ops::newlink()
+ *
+ * @src_net: Source netns of rtnetlink socket
+ * @link_net: Link netns by IFLA_LINK_NETNSID, NULL if not specified
+ * @peer_net: Peer netns
+ * @tb: IFLA_* attributes
+ * @data: IFLA_INFO_DATA attributes
+ */
+struct rtnl_newlink_params {
+	struct net *src_net;
+	struct net *link_net;
+	struct net *peer_net;
+	struct nlattr **tb;
+	struct nlattr **data;
+};
+
+/* Get effective link netns from newlink params. Generally, this is link_net
+ * and falls back to src_net. But for compatibility, a driver may * choose to
+ * use dev_net(dev) instead.
+ */
+static inline struct net *rtnl_newlink_link_net(struct rtnl_newlink_params *p)
+{
+	return p->link_net ? : p->src_net;
+}
+
+/* Get peer netns from newlink params. Fallback to link netns if peer netns is
+ * not specified explicitly.
+ */
+static inline struct net *rtnl_newlink_peer_net(struct rtnl_newlink_params *p)
+{
+	return p->peer_net ? : rtnl_newlink_link_net(p);
+}
+
 /**
  *	struct rtnl_link_ops - rtnetlink link operations
  *
@@ -125,10 +159,8 @@ struct rtnl_link_ops {
 					    struct nlattr *data[],
 					    struct netlink_ext_ack *extack);
 
-	int			(*newlink)(struct net *src_net,
-					   struct net_device *dev,
-					   struct nlattr *tb[],
-					   struct nlattr *data[],
+	int			(*newlink)(struct net_device *dev,
+					   struct rtnl_newlink_params *params,
 					   struct netlink_ext_ack *extack);
 	int			(*changelink)(struct net_device *dev,
 					      struct nlattr *tb[],

net/8021q/vlan_netlink.c

@@ -135,11 +135,14 @@ static int vlan_changelink(struct net_device *dev, struct nlattr *tb[],
 	return 0;
 }
 
-static int vlan_newlink(struct net *src_net, struct net_device *dev,
-			struct nlattr *tb[], struct nlattr *data[],
+static int vlan_newlink(struct net_device *dev,
+			struct rtnl_newlink_params *params,
 			struct netlink_ext_ack *extack)
 {
+	struct net *link_net = rtnl_newlink_link_net(params);
 	struct vlan_dev_priv *vlan = vlan_dev_priv(dev);
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	struct net_device *real_dev;
 	unsigned int max_mtu;
 	__be16 proto;
@@ -155,7 +158,7 @@ static int vlan_newlink(struct net *src_net, struct net_device *dev,
 		return -EINVAL;
 	}
 
-	real_dev = __dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
+	real_dev = __dev_get_by_index(link_net, nla_get_u32(tb[IFLA_LINK]));
 	if (!real_dev) {
 		NL_SET_ERR_MSG_MOD(extack, "link does not exist");
 		return -ENODEV;

net/batman-adv/soft-interface.c

@@ -1063,19 +1063,18 @@ static int batadv_softif_validate(struct nlattr *tb[], struct nlattr *data[],
 
 /**
  * batadv_softif_newlink() - pre-initialize and register new batadv link
- * @src_net: the applicable net namespace
  * @dev: network device to register
- * @tb: IFLA_INFO_DATA netlink attributes
- * @data: enum batadv_ifla_attrs attributes
+ * @params: rtnl newlink parameters
  * @extack: extended ACK report struct
  *
  * Return: 0 if successful or error otherwise.
  */
-static int batadv_softif_newlink(struct net *src_net, struct net_device *dev,
-				 struct nlattr *tb[], struct nlattr *data[],
+static int batadv_softif_newlink(struct net_device *dev,
+				 struct rtnl_newlink_params *params,
 				 struct netlink_ext_ack *extack)
 {
 	struct batadv_priv *bat_priv = netdev_priv(dev);
+	struct nlattr **data = params->data;
 	const char *algo_name;
 	int err;
 

net/bridge/br_netlink.c

@@ -1573,11 +1573,13 @@ static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
 	return 0;
 }
 
-static int br_dev_newlink(struct net *src_net, struct net_device *dev,
-			  struct nlattr *tb[], struct nlattr *data[],
+static int br_dev_newlink(struct net_device *dev,
+			  struct rtnl_newlink_params *params,
 			  struct netlink_ext_ack *extack)
 {
 	struct net_bridge *br = netdev_priv(dev);
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	int err;
 
 	err = register_netdevice(dev);

net/caif/chnl_net.c

@@ -438,10 +438,11 @@ static void caif_netlink_parms(struct nlattr *data[],
 	}
 }
 
-static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
-			  struct nlattr *tb[], struct nlattr *data[],
+static int ipcaif_newlink(struct net_device *dev,
+			  struct rtnl_newlink_params *params,
 			  struct netlink_ext_ack *extack)
 {
+	struct nlattr **data = params->data;
 	int ret;
 	struct chnl_net *caifdev;
 	ASSERT_RTNL();

net/core/rtnetlink.c

@@ -3803,7 +3803,13 @@ static int rtnl_newlink_create(struct sk_buff *skb, struct ifinfomsg *ifm,
 			       struct netlink_ext_ack *extack)
 {
 	unsigned char name_assign_type = NET_NAME_USER;
-	struct net *net = sock_net(skb->sk);
+	struct rtnl_newlink_params params = {
+		.src_net = sock_net(skb->sk),
+		.link_net = link_net,
+		.peer_net = peer_net,
+		.tb = tb,
+		.data = data,
+	};
 	u32 portid = NETLINK_CB(skb).portid;
 	struct net_device *dev;
 	char ifname[IFNAMSIZ];
@@ -3819,8 +3825,8 @@ static int rtnl_newlink_create(struct sk_buff *skb, struct ifinfomsg *ifm,
 		name_assign_type = NET_NAME_ENUM;
 	}
 
-	dev = rtnl_create_link(link_net ? : tgt_net, ifname,
-			       name_assign_type, ops, tb, extack);
+	dev = rtnl_create_link(tgt_net, ifname, name_assign_type, ops, tb,
+			       extack);
 	if (IS_ERR(dev)) {
 		err = PTR_ERR(dev);
 		goto out;
@@ -3828,13 +3834,8 @@ static int rtnl_newlink_create(struct sk_buff *skb, struct ifinfomsg *ifm,
 
 	dev->ifindex = ifm->ifi_index;
 
-	if (link_net)
-		net = link_net;
-	if (peer_net)
-		net = peer_net;
-
 	if (ops->newlink)
-		err = ops->newlink(net, dev, tb, data, extack);
+		err = ops->newlink(dev, &params, extack);
 	else
 		err = register_netdevice(dev);
 	if (err < 0) {
@@ -3847,11 +3848,6 @@ static int rtnl_newlink_create(struct sk_buff *skb, struct ifinfomsg *ifm,
 	err = rtnl_configure_link(dev, ifm, portid, nlh);
 	if (err < 0)
 		goto out_unregister;
-	if (link_net) {
-		err = dev_change_net_namespace(dev, tgt_net, ifname);
-		if (err < 0)
-			goto out_unregister;
-	}
 	if (tb[IFLA_MASTER]) {
 		err = do_set_master(dev, nla_get_u32(tb[IFLA_MASTER]), extack);
 		if (err)
@@ -3922,20 +3918,26 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
 {
 	struct nlattr ** const tb = tbs->tb;
 	struct net *net = sock_net(skb->sk);
+	struct net *device_net;
 	struct net_device *dev;
 	struct ifinfomsg *ifm;
 	bool link_specified;
 
+	/* When creating, lookup for existing device in target net namespace */
+	device_net = (nlh->nlmsg_flags & NLM_F_CREATE) &&
+		     (nlh->nlmsg_flags & NLM_F_EXCL) ?
+		     tgt_net : net;
+
 	ifm = nlmsg_data(nlh);
 	if (ifm->ifi_index > 0) {
 		link_specified = true;
-		dev = __dev_get_by_index(net, ifm->ifi_index);
+		dev = __dev_get_by_index(device_net, ifm->ifi_index);
 	} else if (ifm->ifi_index < 0) {
 		NL_SET_ERR_MSG(extack, "ifindex can't be negative");
 		return -EINVAL;
 	} else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME]) {
 		link_specified = true;
-		dev = rtnl_dev_get(net, tb);
+		dev = rtnl_dev_get(device_net, tb);
 	} else {
 		link_specified = false;
 		dev = NULL;

net/hsr/hsr_netlink.c

@@ -29,16 +29,18 @@ static const struct nla_policy hsr_policy[IFLA_HSR_MAX + 1] = {
 /* Here, it seems a netdevice has already been allocated for us, and the
  * hsr_dev_setup routine has been executed. Nice!
  */
-static int hsr_newlink(struct net *src_net, struct net_device *dev,
-		       struct nlattr *tb[], struct nlattr *data[],
+static int hsr_newlink(struct net_device *dev,
+		       struct rtnl_newlink_params *params,
 		       struct netlink_ext_ack *extack)
 {
+	struct net *link_net = rtnl_newlink_link_net(params);
 	struct net_device *link[2], *interlink = NULL;
+	struct nlattr **data = params->data;
 	enum hsr_version proto_version;
 	unsigned char multicast_spec;
 	u8 proto = HSR_PROTOCOL_HSR;
 
-	if (!net_eq(src_net, dev_net(dev))) {
+	if (!net_eq(link_net, dev_net(dev))) {
 		NL_SET_ERR_MSG_MOD(extack,
 				   "HSR slaves/interlink must be on the same net namespace than HSR link");
 		return -EINVAL;
@@ -52,7 +54,7 @@ static int hsr_newlink(struct net *src_net, struct net_device *dev,
 		NL_SET_ERR_MSG_MOD(extack, "Slave1 device not specified");
 		return -EINVAL;
 	}
-	link[0] = __dev_get_by_index(src_net,
+	link[0] = __dev_get_by_index(link_net,
 				     nla_get_u32(data[IFLA_HSR_SLAVE1]));
 	if (!link[0]) {
 		NL_SET_ERR_MSG_MOD(extack, "Slave1 does not exist");
@@ -62,7 +64,7 @@ static int hsr_newlink(struct net *src_net, struct net_device *dev,
 		NL_SET_ERR_MSG_MOD(extack, "Slave2 device not specified");
 		return -EINVAL;
 	}
-	link[1] = __dev_get_by_index(src_net,
+	link[1] = __dev_get_by_index(link_net,
 				     nla_get_u32(data[IFLA_HSR_SLAVE2]));
 	if (!link[1]) {
 		NL_SET_ERR_MSG_MOD(extack, "Slave2 does not exist");
@@ -75,7 +77,7 @@ static int hsr_newlink(struct net *src_net, struct net_device *dev,
 	}
 
 	if (data[IFLA_HSR_INTERLINK])
-		interlink = __dev_get_by_index(src_net,
+		interlink = __dev_get_by_index(link_net,
 					       nla_get_u32(data[IFLA_HSR_INTERLINK]));
 
 	if (interlink && interlink == link[0]) {

net/ieee802154/6lowpan/core.c

@@ -130,10 +130,11 @@ static int lowpan_validate(struct nlattr *tb[], struct nlattr *data[],
 	return 0;
 }
 
-static int lowpan_newlink(struct net *src_net, struct net_device *ldev,
-			  struct nlattr *tb[], struct nlattr *data[],
+static int lowpan_newlink(struct net_device *ldev,
+			  struct rtnl_newlink_params *params,
 			  struct netlink_ext_ack *extack)
 {
+	struct nlattr **tb = params->tb;
 	struct net_device *wdev;
 	int ret;
 
@@ -143,6 +144,8 @@ static int lowpan_newlink(struct net *src_net, struct net_device *ldev,
 
 	if (!tb[IFLA_LINK])
 		return -EINVAL;
+	if (params->link_net && !net_eq(params->link_net, dev_net(ldev)))
+		return -EINVAL;
 	/* find and hold wpan device */
 	wdev = dev_get_by_index(dev_net(ldev), nla_get_u32(tb[IFLA_LINK]));
 	if (!wdev)

net/ipv4/ip_gre.c

@@ -1397,10 +1397,12 @@ ipgre_newlink_encap_setup(struct net_device *dev, struct nlattr *data[])
 	return 0;
 }
 
-static int ipgre_newlink(struct net *src_net, struct net_device *dev,
-			 struct nlattr *tb[], struct nlattr *data[],
+static int ipgre_newlink(struct net_device *dev,
+			 struct rtnl_newlink_params *params,
 			 struct netlink_ext_ack *extack)
 {
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	struct ip_tunnel_parm_kern p;
 	__u32 fwmark = 0;
 	int err;
@@ -1412,13 +1414,16 @@ static int ipgre_newlink(struct net *src_net, 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,
+				 fwmark);
 }
 
-static int erspan_newlink(struct net *src_net, struct net_device *dev,
-			  struct nlattr *tb[], struct nlattr *data[],
+static int erspan_newlink(struct net_device *dev,
+			  struct rtnl_newlink_params *params,
 			  struct netlink_ext_ack *extack)
 {
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	struct ip_tunnel_parm_kern p;
 	__u32 fwmark = 0;
 	int err;
@@ -1430,7 +1435,8 @@ static int erspan_newlink(struct net *src_net, struct net_device *dev,
 	err = erspan_netlink_parms(dev, data, tb, &p, &fwmark);
 	if (err)
 		return err;
-	return ip_tunnel_newlink(dev, tb, &p, fwmark);
+	return ip_tunnel_newlink(params->link_net ? : dev_net(dev), dev, tb, &p,
+				 fwmark);
 }
 
 static int ipgre_changelink(struct net_device *dev, struct nlattr *tb[],
@@ -1698,6 +1704,7 @@ static struct rtnl_link_ops erspan_link_ops __read_mostly = {
 struct net_device *gretap_fb_dev_create(struct net *net, const char *name,
 					u8 name_assign_type)
 {
+	struct rtnl_newlink_params params = { .src_net = net };
 	struct nlattr *tb[IFLA_MAX + 1];
 	struct net_device *dev;
 	LIST_HEAD(list_kill);
@@ -1705,6 +1712,7 @@ struct net_device *gretap_fb_dev_create(struct net *net, const char *name,
 	int err;
 
 	memset(&tb, 0, sizeof(tb));
+	params.tb = tb;
 
 	dev = rtnl_create_link(net, name, name_assign_type,
 			       &ipgre_tap_ops, tb, NULL);
@@ -1715,7 +1723,7 @@ struct net_device *gretap_fb_dev_create(struct net *net, const char *name,
 	t = netdev_priv(dev);
 	t->collect_md = true;
 
-	err = ipgre_newlink(net, dev, tb, NULL, NULL);
+	err = ipgre_newlink(dev, &params, NULL);
 	if (err < 0) {
 		free_netdev(dev);
 		return ERR_PTR(err);

net/ipv4/ip_tunnel.c

@@ -1189,11 +1189,11 @@ void ip_tunnel_delete_net(struct net *net, unsigned int id,
 }
 EXPORT_SYMBOL_GPL(ip_tunnel_delete_net);
 
-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;
@@ -1302,7 +1302,6 @@ int __ip_tunnel_init(struct net_device *dev)
 	}
 
 	tunnel->dev = dev;
-	tunnel->net = dev_net(dev);
 	strscpy(tunnel->parms.name, dev->name);
 	iph->version		= 4;
 	iph->ihl		= 5;

net/ipv4/ip_vti.c

@@ -574,15 +574,18 @@ static void vti_netlink_parms(struct nlattr *data[],
 		*fwmark = nla_get_u32(data[IFLA_VTI_FWMARK]);
 }
 
-static int vti_newlink(struct net *src_net, struct net_device *dev,
-		       struct nlattr *tb[], struct nlattr *data[],
+static int vti_newlink(struct net_device *dev,
+		       struct rtnl_newlink_params *params,
 		       struct netlink_ext_ack *extack)
 {
+	struct nlattr **data = params->data;
 	struct ip_tunnel_parm_kern parms;
+	struct nlattr **tb = params->tb;
 	__u32 fwmark = 0;
 
 	vti_netlink_parms(data, &parms, &fwmark);
-	return ip_tunnel_newlink(dev, tb, &parms, fwmark);
+	return ip_tunnel_newlink(params->link_net ? : dev_net(dev), dev, tb,
+				 &parms, fwmark);
 }
 
 static int vti_changelink(struct net_device *dev, struct nlattr *tb[],

net/ipv4/ipip.c

@@ -461,11 +461,13 @@ static void ipip_netlink_parms(struct nlattr *data[],
 		*fwmark = nla_get_u32(data[IFLA_IPTUN_FWMARK]);
 }
 
-static int ipip_newlink(struct net *src_net, struct net_device *dev,
-			struct nlattr *tb[], struct nlattr *data[],
+static int ipip_newlink(struct net_device *dev,
+			struct rtnl_newlink_params *params,
 			struct netlink_ext_ack *extack)
 {
 	struct ip_tunnel *t = netdev_priv(dev);
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	struct ip_tunnel_encap ipencap;
 	struct ip_tunnel_parm_kern p;
 	__u32 fwmark = 0;
@@ -478,7 +480,8 @@ static int ipip_newlink(struct net *src_net, struct net_device *dev,
 	}
 
 	ipip_netlink_parms(data, &p, &t->collect_md, &fwmark);
-	return ip_tunnel_newlink(dev, tb, &p, fwmark);
+	return ip_tunnel_newlink(params->link_net ? : dev_net(dev), dev, tb, &p,
+				 fwmark);
 }
 
 static int ipip_changelink(struct net_device *dev, struct nlattr *tb[],

net/ipv6/ip6_gre.c

@@ -1510,7 +1510,6 @@ static int ip6gre_tunnel_init_common(struct net_device *dev)
 	tunnel = netdev_priv(dev);
 
 	tunnel->dev = dev;
-	tunnel->net = dev_net(dev);
 	strcpy(tunnel->parms.name, dev->name);
 
 	ret = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
@@ -1884,7 +1883,6 @@ static int ip6erspan_tap_init(struct net_device *dev)
 	tunnel = netdev_priv(dev);
 
 	tunnel->dev = dev;
-	tunnel->net = dev_net(dev);
 	strcpy(tunnel->parms.name, dev->name);
 
 	ret = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
@@ -1973,7 +1971,7 @@ 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)
 {
@@ -1994,7 +1992,7 @@ 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)
@@ -2007,12 +2005,14 @@ out:
 	return err;
 }
 
-static int ip6gre_newlink(struct net *src_net, struct net_device *dev,
-			  struct nlattr *tb[], struct nlattr *data[],
+static int ip6gre_newlink(struct net_device *dev,
+			  struct rtnl_newlink_params *params,
 			  struct netlink_ext_ack *extack)
 {
+	struct net *net = params->link_net ? : dev_net(dev);
 	struct ip6_tnl *nt = netdev_priv(dev);
-	struct net *net = dev_net(dev);
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	struct ip6gre_net *ign;
 	int err;
 
@@ -2027,7 +2027,7 @@ static int ip6gre_newlink(struct net *src_net, struct net_device *dev,
 			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);
@@ -2243,12 +2243,14 @@ static void ip6erspan_tap_setup(struct net_device *dev)
 	netif_keep_dst(dev);
 }
 
-static int ip6erspan_newlink(struct net *src_net, struct net_device *dev,
-			     struct nlattr *tb[], struct nlattr *data[],
+static int ip6erspan_newlink(struct net_device *dev,
+			     struct rtnl_newlink_params *params,
 			     struct netlink_ext_ack *extack)
 {
+	struct net *net = params->link_net ? : dev_net(dev);
 	struct ip6_tnl *nt = netdev_priv(dev);
-	struct net *net = dev_net(dev);
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	struct ip6gre_net *ign;
 	int err;
 
@@ -2264,7 +2266,7 @@ static int ip6erspan_newlink(struct net *src_net, struct net_device *dev,
 			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);

net/ipv6/ip6_tunnel.c

@@ -254,8 +254,7 @@ 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;
@@ -1921,7 +1920,6 @@ ip6_tnl_dev_init_gen(struct net_device *dev)
 	int t_hlen;
 
 	t->dev = dev;
-	t->net = dev_net(dev);
 
 	ret = dst_cache_init(&t->dst_cache, GFP_KERNEL);
 	if (ret)
@@ -1983,6 +1981,7 @@ static int __net_init ip6_fb_tnl_dev_init(struct net_device *dev)
 	struct net *net = dev_net(dev);
 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
 
+	t->net = net;
 	t->parms.proto = IPPROTO_IPV6;
 
 	rcu_assign_pointer(ip6n->tnls_wc[0], t);
@@ -2045,17 +2044,22 @@ static void ip6_tnl_netlink_parms(struct nlattr *data[],
 		parms->fwmark = nla_get_u32(data[IFLA_IPTUN_FWMARK]);
 }
 
-static int ip6_tnl_newlink(struct net *src_net, struct net_device *dev,
-			   struct nlattr *tb[], struct nlattr *data[],
+static int ip6_tnl_newlink(struct net_device *dev,
+			   struct rtnl_newlink_params *params,
 			   struct netlink_ext_ack *extack)
 {
-	struct net *net = dev_net(dev);
-	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	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);

net/ipv6/ip6_vti.c

@@ -178,8 +178,7 @@ 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;
@@ -926,7 +925,6 @@ 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);
 	netdev_hold(dev, &t->dev_tracker, GFP_KERNEL);
 	netdev_lockdep_set_classes(dev);
 	return 0;
@@ -959,6 +957,7 @@ static int __net_init vti6_fb_tnl_dev_init(struct net_device *dev)
 	struct net *net = dev_net(dev);
 	struct vti6_net *ip6n = net_generic(net, vti6_net_id);
 
+	t->net = net;
 	t->parms.proto = IPPROTO_IPV6;
 
 	rcu_assign_pointer(ip6n->tnls_wc[0], t);
@@ -998,17 +997,20 @@ static void vti6_netlink_parms(struct nlattr *data[],
 		parms->fwmark = nla_get_u32(data[IFLA_VTI_FWMARK]);
 }
 
-static int vti6_newlink(struct net *src_net, struct net_device *dev,
-			struct nlattr *tb[], struct nlattr *data[],
+static int vti6_newlink(struct net_device *dev,
+			struct rtnl_newlink_params *params,
 			struct netlink_ext_ack *extack)
 {
-	struct net *net = dev_net(dev);
+	struct nlattr **data = params->data;
 	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;

net/ipv6/sit.c

@@ -202,8 +202,7 @@ 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->net = net;
 	nt->parms = *parms;
 	if (ipip6_tunnel_create(dev) < 0)
 		goto failed_free;
@@ -1450,7 +1450,6 @@ static int ipip6_tunnel_init(struct net_device *dev)
 	int err;
 
 	tunnel->dev = dev;
-	tunnel->net = dev_net(dev);
 	strcpy(tunnel->parms.name, dev->name);
 
 	ipip6_tunnel_bind_dev(dev);
@@ -1551,19 +1550,23 @@ static bool ipip6_netlink_6rd_parms(struct nlattr *data[],
 }
 #endif
 
-static int ipip6_newlink(struct net *src_net, struct net_device *dev,
-			 struct nlattr *tb[], struct nlattr *data[],
+static int ipip6_newlink(struct net_device *dev,
+			 struct rtnl_newlink_params *params,
 			 struct netlink_ext_ack *extack)
 {
-	struct net *net = dev_net(dev);
+	struct nlattr **data = params->data;
+	struct nlattr **tb = params->tb;
 	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);
@@ -1858,6 +1861,9 @@ static int __net_init sit_init_net(struct net *net)
 	 */
 	sitn->fb_tunnel_dev->netns_immutable = true;
 
+	t = netdev_priv(sitn->fb_tunnel_dev);
+	t->net = net;
+
 	err = register_netdev(sitn->fb_tunnel_dev);
 	if (err)
 		goto err_reg_dev;
@@ -1865,8 +1871,6 @@ static int __net_init sit_init_net(struct net *net)
 	ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
 	ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
 
-	t = netdev_priv(sitn->fb_tunnel_dev);
-
 	strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
 	return 0;
 

net/xfrm/xfrm_interface_core.c

@@ -242,10 +242,9 @@ static void xfrmi_dev_free(struct net_device *dev)
 	gro_cells_destroy(&xi->gro_cells);
 }
 
-static int xfrmi_create(struct net_device *dev)
+static int xfrmi_create(struct net *net, struct net_device *dev)
 {
 	struct xfrm_if *xi = netdev_priv(dev);
-	struct net *net = dev_net(dev);
 	struct xfrmi_net *xfrmn = net_generic(net, xfrmi_net_id);
 	int err;
 
@@ -814,15 +813,17 @@ static void xfrmi_netlink_parms(struct nlattr *data[],
 		parms->collect_md = true;
 }
 
-static int xfrmi_newlink(struct net *src_net, struct net_device *dev,
-			struct nlattr *tb[], struct nlattr *data[],
-			struct netlink_ext_ack *extack)
+static int xfrmi_newlink(struct net_device *dev,
+			 struct rtnl_newlink_params *params,
+			 struct netlink_ext_ack *extack)
 {
-	struct net *net = dev_net(dev);
+	struct nlattr **data = params->data;
 	struct xfrm_if_parms p = {};
 	struct xfrm_if *xi;
+	struct net *net;
 	int err;
 
+	net = params->link_net ? : dev_net(dev);
 	xfrmi_netlink_parms(data, &p);
 	if (p.collect_md) {
 		struct xfrmi_net *xfrmn = net_generic(net, xfrmi_net_id);
@@ -851,7 +852,7 @@ static int xfrmi_newlink(struct net *src_net, struct net_device *dev,
 	xi->net = net;
 	xi->dev = dev;
 
-	err = xfrmi_create(dev);
+	err = xfrmi_create(net, dev);
 	return err;
 }
 

tools/testing/selftests/net/Makefile

@@ -48,6 +48,7 @@ TEST_PROGS := \
 	ipv6_route_update_soft_lockup.sh \
 	l2_tos_ttl_inherit.sh \
 	l2tp.sh \
+	link_netns.py \
 	msg_zerocopy.sh \
 	nat6to4.sh \
 	ndisc_unsolicited_na_test.sh \

tools/testing/selftests/net/config

@@ -110,3 +110,8 @@ CONFIG_VLAN_8021Q=y
 CONFIG_VXLAN=m
 CONFIG_XFRM_INTERFACE=m
 CONFIG_XFRM_USER=m
+CONFIG_IPVLAN=m
+CONFIG_CAN=m
+CONFIG_CAN_DEV=m
+CONFIG_CAN_VXCAN=m
+CONFIG_NETKIT=y

tools/testing/selftests/net/lib/py/__init__.py

@@ -2,7 +2,7 @@
 
 from .consts import KSRC
 from .ksft import *
-from .netns import NetNS
+from .netns import NetNS, NetNSEnter
 from .nsim import *
 from .utils import *
 from .ynl import NlError, YnlFamily, EthtoolFamily, NetdevFamily, RtnlFamily, RtnlAddrFamily

tools/testing/selftests/net/lib/py/netns.py

@@ -1,9 +1,12 @@
 # SPDX-License-Identifier: GPL-2.0
 
 from .utils import ip
+import ctypes
 import random
 import string
 
+libc = ctypes.cdll.LoadLibrary('libc.so.6')
+
 
 class NetNS:
     def __init__(self, name=None):
@@ -29,3 +32,18 @@ class NetNS:
 
     def __repr__(self):
         return f"NetNS({self.name})"
+
+
+class NetNSEnter:
+    def __init__(self, ns_name):
+        self.ns_path = f"/run/netns/{ns_name}"
+
+    def __enter__(self):
+        self.saved = open("/proc/thread-self/ns/net")
+        with open(self.ns_path) as ns_file:
+            libc.setns(ns_file.fileno(), 0)
+        return self
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        libc.setns(self.saved.fileno(), 0)
+        self.saved.close()

tools/testing/selftests/net/link_netns.py

@@ -0,0 +1,141 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+
+import time
+
+from lib.py import ksft_run, ksft_exit, ksft_true
+from lib.py import ip
+from lib.py import NetNS, NetNSEnter
+from lib.py import RtnlFamily
+
+
+LINK_NETNSID = 100
+
+
+def test_event() -> None:
+    with NetNS() as ns1, NetNS() as ns2:
+        with NetNSEnter(str(ns2)):
+            rtnl = RtnlFamily()
+
+        rtnl.ntf_subscribe("rtnlgrp-link")
+
+        ip(f"netns set {ns2} {LINK_NETNSID}", ns=str(ns1))
+        ip(f"link add netns {ns1} link-netnsid {LINK_NETNSID} dummy1 type dummy")
+        ip(f"link add netns {ns1} dummy2 type dummy", ns=str(ns2))
+
+        ip("link del dummy1", ns=str(ns1))
+        ip("link del dummy2", ns=str(ns1))
+
+        time.sleep(1)
+        rtnl.check_ntf()
+        ksft_true(rtnl.async_msg_queue.empty(),
+                  "Received unexpected link notification")
+
+
+def validate_link_netns(netns, ifname, link_netnsid) -> bool:
+    link_info = ip(f"-d link show dev {ifname}", ns=netns, json=True)
+    if not link_info:
+        return False
+    return link_info[0].get("link_netnsid") == link_netnsid
+
+
+def test_link_net() -> None:
+    configs = [
+        # type, common args, type args, fallback to dev_net
+        ("ipvlan", "link dummy1", "", False),
+        ("macsec", "link dummy1", "", False),
+        ("macvlan", "link dummy1", "", False),
+        ("macvtap", "link dummy1", "", False),
+        ("vlan", "link dummy1", "id 100", False),
+        ("gre", "", "local 192.0.2.1", True),
+        ("vti", "", "local 192.0.2.1", True),
+        ("ipip", "", "local 192.0.2.1", True),
+        ("ip6gre", "", "local 2001:db8::1", True),
+        ("ip6tnl", "", "local 2001:db8::1", True),
+        ("vti6", "", "local 2001:db8::1", True),
+        ("sit", "", "local 192.0.2.1", True),
+        ("xfrm", "", "if_id 1", True),
+    ]
+
+    with NetNS() as ns1, NetNS() as ns2, NetNS() as ns3:
+        net1, net2, net3 = str(ns1), str(ns2), str(ns3)
+
+        # prepare link netnsid  and a dummy link needed by certain drivers
+        ip(f"netns set {net3} {LINK_NETNSID}", ns=str(net2))
+        ip("link add dummy1 type dummy", ns=net3)
+
+        cases = [
+            # source, "netns", "link-netns", expected link-netns
+            (net3, None, None, None, None),
+            (net3, net2, None, None, LINK_NETNSID),
+            (net2, None, net3, LINK_NETNSID, LINK_NETNSID),
+            (net1, net2, net3, LINK_NETNSID, LINK_NETNSID),
+        ]
+
+        for src_net, netns, link_netns, exp1, exp2 in cases:
+            tgt_net = netns or src_net
+            for typ, cargs, targs, fb_dev_net in configs:
+                cmd = "link add"
+                if netns:
+                    cmd += f" netns {netns}"
+                if link_netns:
+                    cmd += f" link-netns {link_netns}"
+                cmd += f" {cargs} foo type {typ} {targs}"
+                ip(cmd, ns=src_net)
+                if fb_dev_net:
+                    ksft_true(validate_link_netns(tgt_net, "foo", exp1),
+                              f"{typ} link_netns validation failed")
+                else:
+                    ksft_true(validate_link_netns(tgt_net, "foo", exp2),
+                              f"{typ} link_netns validation failed")
+                ip(f"link del foo", ns=tgt_net)
+
+
+def test_peer_net() -> None:
+    types = [
+        "vxcan",
+        "netkit",
+        "veth",
+    ]
+
+    with NetNS() as ns1, NetNS() as ns2, NetNS() as ns3, NetNS() as ns4:
+        net1, net2, net3, net4 = str(ns1), str(ns2), str(ns3), str(ns4)
+
+        ip(f"netns set {net3} {LINK_NETNSID}", ns=str(net2))
+
+        cases = [
+            # source, "netns", "link-netns", "peer netns", expected
+            (net1, None, None, None, None),
+            (net1, net2, None, None, None),
+            (net2, None, net3, None, LINK_NETNSID),
+            (net1, net2, net3, None, None),
+            (net2, None, None, net3, LINK_NETNSID),
+            (net1, net2, None, net3, LINK_NETNSID),
+            (net2, None, net2, net3, LINK_NETNSID),
+            (net1, net2, net4, net3, LINK_NETNSID),
+        ]
+
+        for src_net, netns, link_netns, peer_netns, exp in cases:
+            tgt_net = netns or src_net
+            for typ in types:
+                cmd = "link add"
+                if netns:
+                    cmd += f" netns {netns}"
+                if link_netns:
+                    cmd += f" link-netns {link_netns}"
+                cmd += f" foo type {typ}"
+                if peer_netns:
+                    cmd += f" peer netns {peer_netns}"
+                ip(cmd, ns=src_net)
+                ksft_true(validate_link_netns(tgt_net, "foo", exp),
+                          f"{typ} peer_netns validation failed")
+                ip(f"link del foo", ns=tgt_net)
+
+
+def main() -> None:
+    ksft_run([test_event, test_link_net, test_peer_net])
+    ksft_exit()
+
+
+if __name__ == "__main__":
+    main()

tools/testing/selftests/net/netns-name.sh

@@ -83,6 +83,16 @@ ip -netns $NS link show dev $ALT_NAME 2> /dev/null &&
     fail "Can still find alt-name after move"
 ip -netns $test_ns link del $DEV || fail
 
+#
+# Test no conflict of the same name/ifindex in different netns
+#
+ip -netns $NS link add name $DEV index 100 type dummy || fail
+ip -netns $NS link add netns $test_ns name $DEV index 100 type dummy ||
+    fail "Can create in netns without moving"
+ip -netns $test_ns link show dev $DEV >> /dev/null || fail "Device not found"
+ip -netns $NS link del $DEV || fail
+ip -netns $test_ns link del $DEV || fail
+
 echo -ne "$(basename $0) \t\t\t\t"
 if [ $RET_CODE -eq 0 ]; then
     echo "[  OK  ]"