mm: drop useless local parameters of __register_one_node()

__register_one_node() initializes local parameters "p_node" & "parent"
for register_node().

But, register_node() does not use them.

Remove the related code of "parent" node, cleanup __register_one_node()
and register_node().

Link: http://lkml.kernel.org/r/1498013846-20149-1-git-send-email-douly.fnst@cn.fujitsu.comSigned-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/base/node.c

@@ -288,7 +288,7 @@ static void node_device_release(struct device *dev)
  *
  * Initialize and register the node device.
  */
-static int register_node(struct node *node, int num, struct node *parent)
+static int register_node(struct node *node, int num)
 {
 	int error;
 
@@ -567,19 +567,14 @@ static void init_node_hugetlb_work(int nid) { }
 
 int __register_one_node(int nid)
 {
-	int p_node = parent_node(nid);
-	struct node *parent = NULL;
 	int error;
 	int cpu;
 
-	if (p_node != nid)
-		parent = node_devices[p_node];
-
 	node_devices[nid] = kzalloc(sizeof(struct node), GFP_KERNEL);
 	if (!node_devices[nid])
 		return -ENOMEM;
 
-	error = register_node(node_devices[nid], nid, parent);
+	error = register_node(node_devices[nid], nid);
 
 	/* link cpu under this node */
 	for_each_present_cpu(cpu) {