mm/slab.c: use list_for_each_entry in cache_flusharray

Simplify the code with list_for_each_entry().

Signed-off-by: Geliang Tang <geliangtang@163.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/slab.c

@@ -3338,17 +3338,12 @@ free_done:
 #if STATS
 	{
 		int i = 0;
-		struct list_head *p;
+		struct page *page;
 
-		p = n->slabs_free.next;
-		while (p != &(n->slabs_free)) {
-			struct page *page;
-
-			page = list_entry(p, struct page, lru);
+		list_for_each_entry(page, &n->slabs_free, lru) {
 			BUG_ON(page->active);
 
 			i++;
-			p = p->next;
 		}
 		STATS_SET_FREEABLE(cachep, i);
 	}