rds: fix memory leak error

When the function register_netdevice_notifier fails, the memory
allocated by kmem_cache_create should be freed by the function
kmem_cache_destroy.

Cc: Joe Jin <joe.jin@oracle.com>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Signed-off-by: Zhu Yanjun <yanjun.zhu@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Acked-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/rds/tcp.c

@@ -641,12 +641,12 @@ static int rds_tcp_init(void)
 	ret = register_netdevice_notifier(&rds_tcp_dev_notifier);
 	if (ret) {
 		pr_warn("could not register rds_tcp_dev_notifier\n");
-		goto out;
+		goto out_slab;
 	}
 
 	ret = register_pernet_subsys(&rds_tcp_net_ops);
 	if (ret)
-		goto out_slab;
+		goto out_notifier;
 
 	ret = rds_tcp_recv_init();
 	if (ret)
@@ -664,9 +664,10 @@ out_recv:
 	rds_tcp_recv_exit();
 out_pernet:
 	unregister_pernet_subsys(&rds_tcp_net_ops);
-out_slab:
+out_notifier:
 	if (unregister_netdevice_notifier(&rds_tcp_dev_notifier))
 		pr_warn("could not unregister rds_tcp_dev_notifier\n");
+out_slab:
 	kmem_cache_destroy(rds_tcp_conn_slab);
 out:
 	return ret;