[PATCH 13/15] mm/page_alloc, folio: use folio_page() when freeing folios

[Nilay Vaish]

As part of the memdescs effort, struct folio will be allocated
separately from struct page and will no longer overlay the head page.

Replace &folio->page with folio_page(folio, 0) in __folio_put() and
free_unref_folios().

No functional change intended.

Assisted-by: LLM
Signed-off-by: Nilay Vaish <nilayvaish@xxxxxxxxxx>
---
 mm/folio.c      |  2 +-
 mm/page_alloc.c | 18 ++++++++++--------
 2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/mm/folio.c b/mm/folio.c
index 35e242b48870..978565add078 100644
--- a/mm/folio.c
+++ b/mm/folio.c
@@ -103,7 +103,7 @@ void __folio_put(struct folio *folio)
 	page_cache_release(folio);
 	folio_unqueue_deferred_split(folio);
 	mem_cgroup_uncharge(folio);
-	free_frozen_pages(&folio->page, folio_order(folio));
+	free_frozen_pages(folio_page(folio, 0), folio_order(folio));
 }
 EXPORT_SYMBOL(__folio_put);
 
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 07e03c7c7771..2f8cd3da199d 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3006,17 +3006,18 @@ void free_unref_folios(struct folio_batch *folios)
 	/* Prepare folios for freeing */
 	for (i = 0, j = 0; i < folios->nr; i++) {
 		struct folio *folio = folios->folios[i];
+		struct page *page = folio_page(folio, 0);
 		unsigned long pfn = folio_pfn(folio);
 		unsigned int order = folio_order(folio);
 
-		if (!__free_pages_prepare(&folio->page, order, FPI_NONE))
+		if (!__free_pages_prepare(page, order, FPI_NONE))
 			continue;
 		/*
 		 * Free orders not handled on the PCP directly to the
 		 * allocator.
 		 */
 		if (!pcp_allowed_order(order)) {
-			free_one_page(folio_zone(folio), &folio->page,
+			free_one_page(folio_zone(folio), page,
 				      pfn, order, FPI_NONE);
 			continue;
 		}
@@ -3029,13 +3030,14 @@ void free_unref_folios(struct folio_batch *folios)
 
 	for (i = 0; i < folios->nr; i++) {
 		struct folio *folio = folios->folios[i];
+		struct page *page = folio_page(folio, 0);
 		struct zone *zone = folio_zone(folio);
 		unsigned long pfn = folio_pfn(folio);
 		unsigned int order = (unsigned long)folio->private;
 		int migratetype;
 
 		folio->private = NULL;
-		migratetype = get_pfnblock_migratetype(&folio->page, pfn);
+		migratetype = get_pfnblock_migratetype(page, pfn);
 
 		/* Different zone requires a different pcp lock */
 		if (zone != locked_zone ||
@@ -3051,7 +3053,7 @@ void free_unref_folios(struct folio_batch *folios)
 			 * allocator, see comment in free_frozen_pages.
 			 */
 			if (is_migrate_isolate(migratetype)) {
-				free_one_page(zone, &folio->page, pfn,
+				free_one_page(zone, page, pfn,
 					      order, FPI_NONE);
 				continue;
 			}
@@ -3062,7 +3064,7 @@ void free_unref_folios(struct folio_batch *folios)
 			 */
 			pcp = pcp_spin_trylock(zone->per_cpu_pageset);
 			if (unlikely(!pcp)) {
-				free_one_page(zone, &folio->page, pfn,
+				free_one_page(zone, page, pfn,
 					      order, FPI_NONE);
 				continue;
 			}
@@ -3076,9 +3078,9 @@ void free_unref_folios(struct folio_batch *folios)
 		if (unlikely(migratetype >= MIGRATE_PCPTYPES))
 			migratetype = MIGRATE_MOVABLE;
 
-		trace_mm_page_free_batched(&folio->page);
-		if (!free_frozen_page_commit(zone, pcp, &folio->page,
-				migratetype, order, FPI_NONE)) {
+		trace_mm_page_free_batched(page);
+		if (!free_frozen_page_commit(zone, pcp, page,
+					     migratetype, order, FPI_NONE)) {
 			pcp = NULL;
 			locked_zone = NULL;
 		}
-- 
2.56.0.rc1.315.gc6ed9934b7-goog