Merge branch 'netdev_iflink_remove'

Nicolas Dichtel says:

====================
Remove iflink field from the net_device structure

The first goal of this series was to advertise the veth peer via the IFLA_LINK
attribute, but iflink was not ready for network namespaces.

The iflink of an interface should be set to its ifindex for a physical interface
and to another value (0 if not relevant) for a virtual interface.
This was not the case for some interfaces, like vxlan, bond, or bridge for
example.
There is also a risk, if the targeted interface moves to another netns, that the
ifindex changes without updating corresponding iflink fields (eg. vlan).

Moving the management of this property into virtual interface drivers allows to
better handle this last case because most of virtual interface drivers have a
pointer to the link netdevice.
Anyway, dev->iflink value was always a copy of some internal data of the virtual
interface driver, thus let's use these internal data directly.

So, this series removes the iflink field and let the drivers manage it.
Only the last patch was present in the v1, but I fully rework it.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 21 insertions, 16 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 5c9e94cb1b2c..37b70e82bff8 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -4858,8 +4858,8 @@ static int inet6_fill_ifinfo(struct sk_buff *skb, struct inet6_dev *idev,
 	    (dev->addr_len &&
 	     nla_put(skb, IFLA_ADDRESS, dev->addr_len, dev->dev_addr)) ||
 	    nla_put_u32(skb, IFLA_MTU, dev->mtu) ||
-	    (dev->ifindex != dev->iflink &&
-	     nla_put_u32(skb, IFLA_LINK, dev->iflink)))
+	    (dev->ifindex != dev_get_iflink(dev) &&
+	     nla_put_u32(skb, IFLA_LINK, dev_get_iflink(dev))))
 		goto nla_put_failure;
 	protoinfo = nla_nest_start(skb, IFLA_PROTINFO);
 	if (!protoinfo)
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 0f4e73da14e4..f724329d7436 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -1216,6 +1216,7 @@ static const struct net_device_ops ip6gre_netdev_ops = {
 	.ndo_do_ioctl		= ip6gre_tunnel_ioctl,
 	.ndo_change_mtu		= ip6gre_tunnel_change_mtu,
 	.ndo_get_stats64	= ip_tunnel_get_stats64,
+	.ndo_get_iflink		= ip6_tnl_get_iflink,
 };
 
 static void ip6gre_dev_free(struct net_device *dev)
@@ -1238,7 +1239,6 @@ static void ip6gre_tunnel_setup(struct net_device *dev)
 	if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
 		dev->mtu -= 8;
 	dev->flags |= IFF_NOARP;
-	dev->iflink = 0;
 	dev->addr_len = sizeof(struct in6_addr);
 	netif_keep_dst(dev);
 }
@@ -1270,8 +1270,6 @@ static int ip6gre_tunnel_init(struct net_device *dev)
 		u64_stats_init(&ip6gre_tunnel_stats->syncp);
 	}
 
-	dev->iflink = tunnel->parms.link;
-
 	return 0;
 }
 
@@ -1480,8 +1478,6 @@ static int ip6gre_tap_init(struct net_device *dev)
 	if (!dev->tstats)
 		return -ENOMEM;
 
-	dev->iflink = tunnel->parms.link;
-
 	return 0;
 }
 
@@ -1493,6 +1489,7 @@ static const struct net_device_ops ip6gre_tap_netdev_ops = {
 	.ndo_validate_addr = eth_validate_addr,
 	.ndo_change_mtu = ip6gre_tunnel_change_mtu,
 	.ndo_get_stats64 = ip_tunnel_get_stats64,
+	.ndo_get_iflink = ip6_tnl_get_iflink,
 };
 
 static void ip6gre_tap_setup(struct net_device *dev)
@@ -1503,7 +1500,6 @@ static void ip6gre_tap_setup(struct net_device *dev)
 	dev->netdev_ops = &ip6gre_tap_netdev_ops;
 	dev->destructor = ip6gre_dev_free;
 
-	dev->iflink = 0;
 	dev->features |= NETIF_F_NETNS_LOCAL;
 }
 
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 9bd85f0dff69..b6a211a150b2 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1264,8 +1264,6 @@ static void ip6_tnl_link_config(struct ip6_tnl *t)
 	else
 		dev->flags &= ~IFF_POINTOPOINT;
 
-	dev->iflink = p->link;
-
 	if (p->flags & IP6_TNL_F_CAP_XMIT) {
 		int strict = (ipv6_addr_type(&p->raddr) &
 			      (IPV6_ADDR_MULTICAST|IPV6_ADDR_LINKLOCAL));
@@ -1517,6 +1515,13 @@ ip6_tnl_change_mtu(struct net_device *dev, int new_mtu)
 	return 0;
 }
 
+int ip6_tnl_get_iflink(const struct net_device *dev)
+{
+	struct ip6_tnl *t = netdev_priv(dev);
+
+	return t->parms.link;
+}
+EXPORT_SYMBOL(ip6_tnl_get_iflink);
 
 static const struct net_device_ops ip6_tnl_netdev_ops = {
 	.ndo_init	= ip6_tnl_dev_init,
@@ -1525,6 +1530,7 @@ static const struct net_device_ops ip6_tnl_netdev_ops = {
 	.ndo_do_ioctl	= ip6_tnl_ioctl,
 	.ndo_change_mtu = ip6_tnl_change_mtu,
 	.ndo_get_stats	= ip6_get_stats,
+	.ndo_get_iflink = ip6_tnl_get_iflink,
 };
 
 
diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c
index 53d90ed68905..b53148444e15 100644
--- a/net/ipv6/ip6_vti.c
+++ b/net/ipv6/ip6_vti.c
@@ -601,8 +601,6 @@ static void vti6_link_config(struct ip6_tnl *t)
 		dev->flags |= IFF_POINTOPOINT;
 	else
 		dev->flags &= ~IFF_POINTOPOINT;
-
-	dev->iflink = p->link;
 }
 
 /**
@@ -808,6 +806,7 @@ static const struct net_device_ops vti6_netdev_ops = {
 	.ndo_do_ioctl	= vti6_ioctl,
 	.ndo_change_mtu = vti6_change_mtu,
 	.ndo_get_stats64 = ip_tunnel_get_stats64,
+	.ndo_get_iflink = ip6_tnl_get_iflink,
 };
 
 /**
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index caf6b99374e6..003431f5b4b6 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -718,8 +718,14 @@ static netdev_tx_t reg_vif_xmit(struct sk_buff *skb,
 	return NETDEV_TX_OK;
 }
 
+static int reg_vif_get_iflink(const struct net_device *dev)
+{
+	return 0;
+}
+
 static const struct net_device_ops reg_vif_netdev_ops = {
 	.ndo_start_xmit	= reg_vif_xmit,
+	.ndo_get_iflink = reg_vif_get_iflink,
 };
 
 static void reg_vif_setup(struct net_device *dev)
@@ -752,7 +758,6 @@ static struct net_device *ip6mr_reg_vif(struct net *net, struct mr6_table *mrt)
 		free_netdev(dev);
 		return NULL;
 	}
-	dev->iflink = 0;
 
 	if (dev_open(dev))
 		goto failure;
@@ -992,7 +997,7 @@ static int mif6_add(struct net *net, struct mr6_table *mrt,
 	v->pkt_out = 0;
 	v->link = dev->ifindex;
 	if (v->flags & MIFF_REGISTER)
-		v->link = dev->iflink;
+		v->link = dev_get_iflink(dev);
 
 	/* And finish update writing critical data */
 	write_lock_bh(&mrt_lock);
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index e6b9f51b15e8..6cf2026a9cea 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -1076,7 +1076,6 @@ static void ipip6_tunnel_bind_dev(struct net_device *dev)
 		if (dev->mtu < IPV6_MIN_MTU)
 			dev->mtu = IPV6_MIN_MTU;
 	}
-	dev->iflink = tunnel->parms.link;
 }
 
 static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p)
@@ -1336,6 +1335,7 @@ static const struct net_device_ops ipip6_netdev_ops = {
 	.ndo_do_ioctl	= ipip6_tunnel_ioctl,
 	.ndo_change_mtu	= ipip6_tunnel_change_mtu,
 	.ndo_get_stats64 = ip_tunnel_get_stats64,
+	.ndo_get_iflink = ip_tunnel_get_iflink,
 };
 
 static void ipip6_dev_free(struct net_device *dev)
@@ -1366,7 +1366,6 @@ static void ipip6_tunnel_setup(struct net_device *dev)
 	dev->mtu		= ETH_DATA_LEN - t_hlen;
 	dev->flags		= IFF_NOARP;
 	netif_keep_dst(dev);
-	dev->iflink		= 0;
 	dev->addr_len		= 4;
 	dev->features		|= NETIF_F_LLTX;
 	dev->features		|= SIT_FEATURES;