netns: rename peernet2id() to peernet2id_alloc()

In a following commit, a new function will be introduced to only lookup for
a nsid (no allocation if the nsid doesn't exist). To avoid confusion, the
existing function is renamed.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 666e092..83e0832 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1204,7 +1204,7 @@
 		struct net *link_net = dev->rtnl_link_ops->get_link_net(dev);
 
 		if (!net_eq(dev_net(dev), link_net)) {
-			int id = peernet2id(dev_net(dev), link_net);
+			int id = peernet2id_alloc(dev_net(dev), link_net);
 
 			if (nla_put_s32(skb, IFLA_LINK_NETNSID, id))
 				goto nla_put_failure;