linux-kernel - [PATCH] mm/hugetlb.c: just use put_page_testzero() instead of page

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Date:   Thu, 8 Oct 2020 01:09:49 +0800
From:   Hui Su <sh_def@....com>
To:     mike.kravetz@...cle.com, akpm@...ux-foundation.org,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: [PATCH] mm/hugetlb.c: just use put_page_testzero() instead of
 page_count()

we test the page reference count is zero or not here,
it can be a bug here if page refercence count is not zero.
So we can just use put_page_testzero() instead of
page_count().

Signed-off-by: Hui Su <sh_def@....com>
---
 mm/hugetlb.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 67fc6383995b..a274b9ac466f 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2105,8 +2105,7 @@ static int gather_surplus_pages(struct hstate *h, int delta)
 		 * This page is now managed by the hugetlb allocator and has
 		 * no users -- drop the buddy allocator's reference.
 		 */
-		put_page_testzero(page);
-		VM_BUG_ON_PAGE(page_count(page), page);
+		VM_BUG_ON_PAGE(!put_page_testzero(page), page);
 		enqueue_huge_page(h, page);
 	}
 free:
-- 
2.25.1