At this point, we are in an if branch conditional on
(nr < ENTIRELY_MAPPED), and FOLIO_PAGES_MAPPED is equal to
(ENTIRELY_MAPPED - 1). This means the upper bits are already cleared.

Not necessary to mask off it.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Harry Yoo <harry.yoo@oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: David Hildenbrand <david@redhat.com>

---
v2:
  * adjust the changelog based on Lorenzo's comment
---
 mm/rmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/rmap.c b/mm/rmap.c
index 1c5988dbd1e7..a927437a56c2 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1749,7 +1749,7 @@ static __always_inline void __folio_remove_rmap(struct folio *folio,
 				nr_pages = folio_large_nr_pages(folio);
 				if (level == PGTABLE_LEVEL_PMD)
 					nr_pmdmapped = nr_pages;
-				nr = nr_pages - (nr & FOLIO_PAGES_MAPPED);
+				nr = nr_pages - nr;
 				/* Raced ahead of another remove and an add? */
 				if (unlikely(nr < 0))
 					nr = 0;
-- 
2.34.1