vxlan: call peernet2id() in fdb notification

netns id should be already allocated each time we change
netns, that is, in dev_change_net_namespace() (more precisely
in rtnl_fill_ifinfo()). It is safe to just call peernet2id() here.

Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/vxlan.c

@@ -287,7 +287,7 @@ static int vxlan_fdb_info(struct sk_buff *skb, struct vxlan_dev *vxlan,
 
 	if (!net_eq(dev_net(vxlan->dev), vxlan->net) &&
 	    nla_put_s32(skb, NDA_LINK_NETNSID,
-			peernet2id_alloc(dev_net(vxlan->dev), vxlan->net)))
+			peernet2id(dev_net(vxlan->dev), vxlan->net)))
 		goto nla_put_failure;
 
 	if (send_eth && nla_put(skb, NDA_LLADDR, ETH_ALEN, &fdb->eth_addr))

net/core/net_namespace.c

@@ -227,7 +227,6 @@ int peernet2id_alloc(struct net *net, struct net *peer)
 		rtnl_net_notifyid(net, RTM_NEWNSID, id);
 	return id;
 }
-EXPORT_SYMBOL(peernet2id_alloc);
 
 /* This function returns, if assigned, the id of a peer netns. */
 int peernet2id(struct net *net, struct net *peer)
@@ -240,6 +239,7 @@ int peernet2id(struct net *net, struct net *peer)
 	spin_unlock_irqrestore(&net->nsid_lock, flags);
 	return id;
 }
+EXPORT_SYMBOL(peernet2id);
 
 /* This function returns true is the peer netns has an id assigned into the
  * current netns.