netlink: Fix netlink_insert EADDRINUSE error

The patch c5adde94 ("netlink:
eliminate nl_sk_hash_lock") introduced a bug where the EADDRINUSE
error has been replaced by ENOMEM.  This patch rectifies that
problem.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/netlink/af_netlink.c

@@ -1050,7 +1050,7 @@ netlink_update_listeners(struct sock *sk)
 static int netlink_insert(struct sock *sk, struct net *net, u32 portid)
 {
 	struct netlink_table *table = &nl_table[sk->sk_protocol];
-	int err = -EADDRINUSE;
+	int err;
 
 	lock_sock(sk);
 
@@ -1065,10 +1065,13 @@ static int netlink_insert(struct sock *sk, struct net *net, u32 portid)
 
 	nlk_sk(sk)->portid = portid;
 	sock_hold(sk);
-	if (__netlink_insert(table, sk, net))
-		err = 0;
-	else
+
+	err = 0;
+	if (!__netlink_insert(table, sk, net)) {
+		err = -EADDRINUSE;
 		sock_put(sk);
+	}
+
 err:
 	release_sock(sk);
 	return err;