1 files changed, 11 insertions, 0 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b5a58d476c1a..d73bfad1c32f 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -847,8 +847,19 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order,
                 struct page *page = __rmqueue(zone, order, migratetype);
                 if (unlikely(page == NULL))
                         break;
+
+                /*
+                 * Split buddy pages returned by expand() are received here
+                 * in physical page order. The page is added to the callers and
+                 * list and the list head then moves forward. From the callers
+                 * perspective, the linked list is ordered by page number in
+                 * some conditions. This is useful for IO devices that can
+                 * merge IO requests if the physical pages are ordered
+                 * properly.
+                 */
                 list_add(&page->lru, list);
                 set_page_private(page, migratetype);
+                list = &page->lru;
         }
         spin_unlock(&zone->lock);
         return i;