[PATCH 17/17] gup: Convert check_and_migrate_movable_pages() to use a folio

["Matthew Wilcox (Oracle)" <willy@infradead.org>]

Switch from head pages to folios.  This removes an assumption that
THPs are the only way to have a high-order page.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/gup.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/mm/gup.c b/mm/gup.c
index 76717e05413d..eb7c66e2b785 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1822,41 +1822,41 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages,
 	bool drain_allow = true;
 	LIST_HEAD(movable_page_list);
 	long ret = 0;
-	struct page *prev_head = NULL;
-	struct page *head;
+	struct folio *folio, *prev_folio = NULL;
 	struct migration_target_control mtc = {
 		.nid = NUMA_NO_NODE,
 		.gfp_mask = GFP_USER | __GFP_NOWARN,
 	};
 
 	for (i = 0; i < nr_pages; i++) {
-		head = compound_head(pages[i]);
-		if (head == prev_head)
+		folio = page_folio(pages[i]);
+		if (folio == prev_folio)
 			continue;
-		prev_head = head;
+		prev_folio = folio;
 		/*
 		 * If we get a movable page, since we are going to be pinning
 		 * these entries, try to move them out if possible.
 		 */
-		if (!is_pinnable_page(head)) {
-			if (PageHuge(head)) {
-				if (!isolate_huge_page(head, &movable_page_list))
+		if (!is_pinnable_page(&folio->page)) {
+			if (folio_test_hugetlb(folio)) {
+				if (!isolate_huge_page(&folio->page,
+							&movable_page_list))
 					isolation_error_count++;
 			} else {
-				if (!PageLRU(head) && drain_allow) {
+				if (!folio_test_lru(folio) && drain_allow) {
 					lru_add_drain_all();
 					drain_allow = false;
 				}
 
-				if (isolate_lru_page(head)) {
+				if (isolate_lru_folio(folio)) {
 					isolation_error_count++;
 					continue;
 				}
-				list_add_tail(&head->lru, &movable_page_list);
-				mod_node_page_state(page_pgdat(head),
+				list_add_tail(&folio->lru, &movable_page_list);
+				node_stat_mod_folio(folio,
 						    NR_ISOLATED_ANON +
-						    page_is_file_lru(head),
-						    thp_nr_pages(head));
+						    folio_is_file_lru(folio),
+						    folio_nr_pages(folio));
 			}
 		}
 	}
-- 
2.33.0