[PATCH] mm: memcontrol: replace the loop with a list_for_each_entry()

[Muchun Song <songmuchun@bytedance.com>]

The rule of list walk has gone since:

 commit a9d5adeeb4b2 ("mm/memcontrol: allow to uncharge page without using page->lru field")

So remove the strange comment and replace the loop with a
list_for_each_entry().

Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
 mm/memcontrol.c | 17 ++---------------
 1 file changed, 2 insertions(+), 15 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6c7f1ea3955e..43341bd7ea1c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -6891,24 +6891,11 @@ static void uncharge_page(struct page *page, struct uncharge_gather *ug)
 static void uncharge_list(struct list_head *page_list)
 {
 	struct uncharge_gather ug;
-	struct list_head *next;
+	struct page *page;
 
 	uncharge_gather_clear(&ug);
-
-	/*
-	 * Note that the list can be a single page->lru; hence the
-	 * do-while loop instead of a simple list_for_each_entry().
-	 */
-	next = page_list->next;
-	do {
-		struct page *page;
-
-		page = list_entry(next, struct page, lru);
-		next = page->lru.next;
-
+	list_for_each_entry(page, page_list, lru)
 		uncharge_page(page, &ug);
-	} while (next != page_list);
-
 	uncharge_batch(&ug);
 }
 
-- 
2.11.0