RDS: fix rds_tcp_init() error path

If register_pernet_subsys() fails, we shouldn't try to call
unregister_pernet_subsys().

Fixes: 467fa15356 ("RDS-TCP: Support multiple RDS-TCP listen endpoints, one per netns.")
Cc: stable@vger.kernel.org
Cc: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/rds/tcp.c

@@ -616,7 +616,7 @@ static int rds_tcp_init(void)
 
 	ret = rds_tcp_recv_init();
 	if (ret)
-		goto out_slab;
+		goto out_pernet;
 
 	ret = rds_trans_register(&rds_tcp_transport);
 	if (ret)
@@ -628,8 +628,9 @@ static int rds_tcp_init(void)
 
 out_recv:
 	rds_tcp_recv_exit();
-out_slab:
+out_pernet:
 	unregister_pernet_subsys(&rds_tcp_net_ops);
+out_slab:
 	kmem_cache_destroy(rds_tcp_conn_slab);
 out:
 	return ret;