include/linux/nodemask.h: create next_node_in() helper

Lots of code does

	node = next_node(node, XXX);
	if (node == MAX_NUMNODES)
		node = first_node(XXX);

so create next_node_in() to do this and use it in various places.

[mhocko@suse.com: use next_node_in() helper]
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Laura Abbott <lauraa@codeaurora.org>
Cc: Hui Zhu <zhuhui@xiaomi.com>
Cc: Wang Xiaoqiang <wangxq10@lzu.edu.cn>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index fe787f5..6740c4c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1389,9 +1389,7 @@
 	mem_cgroup_may_update_nodemask(memcg);
 	node = memcg->last_scanned_node;
 
-	node = next_node(node, memcg->scan_nodes);
-	if (node == MAX_NUMNODES)
-		node = first_node(memcg->scan_nodes);
+	node = next_node_in(node, memcg->scan_nodes);
 	/*
 	 * We call this when we hit limit, not when pages are added to LRU.
 	 * No LRU may hold pages because all pages are UNEVICTABLE or