mm/rmap: correct stale comment of rmap_walk_anon and rmap_walk_file

1. update page to folio in comment
2. add comment of new added @locked

Link: https://lkml.kernel.org/r/20230718092136.1935789-1-shikemeng@huaweicloud.comSigned-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/rmap.c

@@ -2397,11 +2397,12 @@ static struct anon_vma *rmap_walk_anon_lock(struct folio *folio,
 /*
  * rmap_walk_anon - do something to anonymous page using the object-based
  * rmap method
- * @page: the page to be handled
+ * @folio: the folio to be handled
  * @rwc: control variable according to each walk type
+ * @locked: caller holds relevant rmap lock
  *
- * Find all the mappings of a page using the mapping pointer and the vma chains
- * contained in the anon_vma struct it points to.
+ * Find all the mappings of a folio using the mapping pointer and the vma
+ * chains contained in the anon_vma struct it points to.
  */
 static void rmap_walk_anon(struct folio *folio,
 		struct rmap_walk_control *rwc, bool locked)
@@ -2445,10 +2446,11 @@ static void rmap_walk_anon(struct folio *folio,
 
 /*
  * rmap_walk_file - do something to file page using the object-based rmap method
- * @page: the page to be handled
+ * @folio: the folio to be handled
  * @rwc: control variable according to each walk type
+ * @locked: caller holds relevant rmap lock
  *
- * Find all the mappings of a page using the mapping pointer and the vma chains
+ * Find all the mappings of a folio using the mapping pointer and the vma chains
  * contained in the address_space struct it points to.
  */
 static void rmap_walk_file(struct folio *folio,