[PATCH] mm/memcg: use get_page() for device private pages in mc_handle_swap_pte()

[Miaohe Lin]

When page table locked is held, the page can't be freed from under us.
So use get_page() to get the extra page reference to simplify the code.
No functional change intended.

Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
---
 mm/memcontrol.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 93e3cc581b51..4ca382efb1ca 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5670,8 +5670,9 @@ static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
 	 */
 	if (is_device_private_entry(ent)) {
 		page = pfn_swap_entry_to_page(ent);
-		if (!get_page_unless_zero(page))
-			return NULL;
+		/* Get a page reference while we know the page can't be freed. */
+		get_page(page);
+
 		return page;
 	}
 
-- 
2.33.0