1 files changed, 27 insertions, 16 deletions

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 90621d498fd1..043e57d08a3e 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -132,6 +132,7 @@ static struct ip6_tnl *ip6gre_tunnel_lookup(struct net_device *dev,
 			gre_proto == htons(ETH_P_ERSPAN2)) ?
 		       ARPHRD_ETHER : ARPHRD_IP6GRE;
 	int score, cand_score = 4;
+	struct net_device *ndev;
 
 	for_each_ip_tunnel_rcu(t, ign->tunnels_r_l[h0 ^ h1]) {
 		if (!ipv6_addr_equal(local, &t->parms.laddr) ||
@@ -243,9 +244,9 @@ static struct ip6_tnl *ip6gre_tunnel_lookup(struct net_device *dev,
 	if (t && t->dev->flags & IFF_UP)
 		return t;
 
-	dev = ign->fb_tunnel_dev;
-	if (dev && dev->flags & IFF_UP)
-		return netdev_priv(dev);
+	ndev = READ_ONCE(ign->fb_tunnel_dev);
+	if (ndev && ndev->flags & IFF_UP)
+		return netdev_priv(ndev);
 
 	return NULL;
 }
@@ -391,7 +392,6 @@ static struct ip6_tnl *ip6gre_tunnel_locate(struct net *net,
 	if (!(nt->parms.o_flags & TUNNEL_SEQ))
 		dev->features |= NETIF_F_LLTX;
 
-	dev_hold(dev);
 	ip6gre_tunnel_link(ign, nt);
 	return nt;
 
@@ -418,6 +418,8 @@ static void ip6gre_tunnel_uninit(struct net_device *dev)
 
 	ip6gre_tunnel_unlink_md(ign, t);
 	ip6gre_tunnel_unlink(ign, t);
+	if (ign->fb_tunnel_dev == dev)
+		WRITE_ONCE(ign->fb_tunnel_dev, NULL);
 	dst_cache_reset(&t->dst_cache);
 	dev_put(dev);
 }
@@ -1137,8 +1139,13 @@ static void ip6gre_tnl_link_config_route(struct ip6_tnl *t, int set_mtu,
 			return;
 
 		if (rt->dst.dev) {
-			dev->needed_headroom = rt->dst.dev->hard_header_len +
-					       t_hlen;
+			unsigned short dst_len = rt->dst.dev->hard_header_len +
+						 t_hlen;
+
+			if (t->dev->header_ops)
+				dev->hard_header_len = dst_len;
+			else
+				dev->needed_headroom = dst_len;
 
 			if (set_mtu) {
 				dev->mtu = rt->dst.dev->mtu - t_hlen;
@@ -1163,7 +1170,12 @@ static int ip6gre_calc_hlen(struct ip6_tnl *tunnel)
 	tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen;
 
 	t_hlen = tunnel->hlen + sizeof(struct ipv6hdr);
-	tunnel->dev->needed_headroom = LL_MAX_HEADER + t_hlen;
+
+	if (tunnel->dev->header_ops)
+		tunnel->dev->hard_header_len = LL_MAX_HEADER + t_hlen;
+	else
+		tunnel->dev->needed_headroom = LL_MAX_HEADER + t_hlen;
+
 	return t_hlen;
 }
 
@@ -1490,6 +1502,7 @@ static int ip6gre_tunnel_init_common(struct net_device *dev)
 	}
 	ip6gre_tnl_init_features(dev);
 
+	dev_hold(dev);
 	return 0;
 
 cleanup_dst_cache_init:
@@ -1532,8 +1545,6 @@ static void ip6gre_fb_tunnel_init(struct net_device *dev)
 	strcpy(tunnel->parms.name, dev->name);
 
 	tunnel->hlen		= sizeof(struct ipv6hdr) + 4;
-
-	dev_hold(dev);
 }
 
 static struct inet6_protocol ip6gre_protocol __read_mostly = {
@@ -1577,17 +1588,18 @@ static void ip6gre_destroy_tunnels(struct net *net, struct list_head *head)
 static int __net_init ip6gre_init_net(struct net *net)
 {
 	struct ip6gre_net *ign = net_generic(net, ip6gre_net_id);
+	struct net_device *ndev;
 	int err;
 
 	if (!net_has_fallback_tunnels(net))
 		return 0;
-	ign->fb_tunnel_dev = alloc_netdev(sizeof(struct ip6_tnl), "ip6gre0",
-					  NET_NAME_UNKNOWN,
-					  ip6gre_tunnel_setup);
-	if (!ign->fb_tunnel_dev) {
+	ndev = alloc_netdev(sizeof(struct ip6_tnl), "ip6gre0",
+			    NET_NAME_UNKNOWN, ip6gre_tunnel_setup);
+	if (!ndev) {
 		err = -ENOMEM;
 		goto err_alloc_dev;
 	}
+	ign->fb_tunnel_dev = ndev;
 	dev_net_set(ign->fb_tunnel_dev, net);
 	/* FB netdevice is special: we have one, and only one per netns.
 	 * Allowing to move it to another netns is clearly unsafe.
@@ -1607,7 +1619,7 @@ static int __net_init ip6gre_init_net(struct net *net)
 	return 0;
 
 err_reg_dev:
-	free_netdev(ign->fb_tunnel_dev);
+	free_netdev(ndev);
 err_alloc_dev:
 	return err;
 }
@@ -1882,6 +1894,7 @@ static int ip6erspan_tap_init(struct net_device *dev)
 	dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
 	ip6erspan_tnl_link_config(tunnel, 1);
 
+	dev_hold(dev);
 	return 0;
 
 cleanup_dst_cache_init:
@@ -1987,8 +2000,6 @@ static int ip6gre_newlink_common(struct net *src_net, struct net_device *dev,
 	if (tb[IFLA_MTU])
 		ip6_tnl_change_mtu(dev, nla_get_u32(tb[IFLA_MTU]));
 
-	dev_hold(dev);
-
 out:
 	return err;
 }