mm/hugetlb.c: correct missing private flag clearing

We should clear the page's private flag when returing the page to the
hugepage pool.  Otherwise, marked hugepage can be allocated to the user
who tries to allocate the non-reserved hugepage.  If this user fail to
map this hugepage, he would try to return the page to the hugepage pool.
Since this page has a private flag, resv_huge_pages would mistakenly
increase.  This patch fixes this situation.

Signed-off-by: Joonsoo Kim <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: "Aneesh Kumar K.V" <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: David Gibson <[email protected]>
Cc: Wanpeng Li <[email protected]>
Cc: Naoya Horiguchi <[email protected]>
Cc: Hillf Danton <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index b49579c7f2a550462c334f97907f2fc131a65e00..691f2264a6ce23cfd10dbb570f5342fee2d25bc5 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -653,6 +653,7 @@ static void free_huge_page(struct page *page)
        BUG_ON(page_count(page));
        BUG_ON(page_mapcount(page));
        restore_reserve = PagePrivate(page);
+       ClearPagePrivate(page);
 
        spin_lock(&hugetlb_lock);
        hugetlb_cgroup_uncharge_page(hstate_index(h),