mm: page_alloc: move mark_free_page() into snapshot.c

The mark_free_page() is only used in kernel/power/snapshot.c, move it out
to reduce a bit of page_alloc.c

Link: https://lkml.kernel.org/r/20230516063821.121844-10-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/suspend.h

@@ -364,9 +364,6 @@ struct pbe {
 	struct pbe *next;
 };
 
-/* mm/page_alloc.c */
-extern void mark_free_pages(struct zone *zone);
-
 /**
  * struct platform_hibernation_ops - hibernation platform support
  *

kernel/power/snapshot.c

@@ -1228,6 +1228,58 @@ unsigned int snapshot_additional_pages(struct zone *zone)
 	return 2 * rtree;
 }
 
+/*
+ * Touch the watchdog for every WD_PAGE_COUNT pages.
+ */
+#define WD_PAGE_COUNT	(128*1024)
+
+static void mark_free_pages(struct zone *zone)
+{
+	unsigned long pfn, max_zone_pfn, page_count = WD_PAGE_COUNT;
+	unsigned long flags;
+	unsigned int order, t;
+	struct page *page;
+
+	if (zone_is_empty(zone))
+		return;
+
+	spin_lock_irqsave(&zone->lock, flags);
+
+	max_zone_pfn = zone_end_pfn(zone);
+	for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
+		if (pfn_valid(pfn)) {
+			page = pfn_to_page(pfn);
+
+			if (!--page_count) {
+				touch_nmi_watchdog();
+				page_count = WD_PAGE_COUNT;
+			}
+
+			if (page_zone(page) != zone)
+				continue;
+
+			if (!swsusp_page_is_forbidden(page))
+				swsusp_unset_page_free(page);
+		}
+
+	for_each_migratetype_order(order, t) {
+		list_for_each_entry(page,
+				&zone->free_area[order].free_list[t], buddy_list) {
+			unsigned long i;
+
+			pfn = page_to_pfn(page);
+			for (i = 0; i < (1UL << order); i++) {
+				if (!--page_count) {
+					touch_nmi_watchdog();
+					page_count = WD_PAGE_COUNT;
+				}
+				swsusp_set_page_free(pfn_to_page(pfn + i));
+			}
+		}
+	}
+	spin_unlock_irqrestore(&zone->lock, flags);
+}
+
 #ifdef CONFIG_HIGHMEM
 /**
  * count_free_highmem_pages - Compute the total number of free highmem pages.

mm/page_alloc.c

@@ -2365,61 +2365,6 @@ void drain_all_pages(struct zone *zone)
 	__drain_all_pages(zone, false);
 }
 
-#ifdef CONFIG_HIBERNATION
-
-/*
- * Touch the watchdog for every WD_PAGE_COUNT pages.
- */
-#define WD_PAGE_COUNT	(128*1024)
-
-void mark_free_pages(struct zone *zone)
-{
-	unsigned long pfn, max_zone_pfn, page_count = WD_PAGE_COUNT;
-	unsigned long flags;
-	unsigned int order, t;
-	struct page *page;
-
-	if (zone_is_empty(zone))
-		return;
-
-	spin_lock_irqsave(&zone->lock, flags);
-
-	max_zone_pfn = zone_end_pfn(zone);
-	for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
-		if (pfn_valid(pfn)) {
-			page = pfn_to_page(pfn);
-
-			if (!--page_count) {
-				touch_nmi_watchdog();
-				page_count = WD_PAGE_COUNT;
-			}
-
-			if (page_zone(page) != zone)
-				continue;
-
-			if (!swsusp_page_is_forbidden(page))
-				swsusp_unset_page_free(page);
-		}
-
-	for_each_migratetype_order(order, t) {
-		list_for_each_entry(page,
-				&zone->free_area[order].free_list[t], buddy_list) {
-			unsigned long i;
-
-			pfn = page_to_pfn(page);
-			for (i = 0; i < (1UL << order); i++) {
-				if (!--page_count) {
-					touch_nmi_watchdog();
-					page_count = WD_PAGE_COUNT;
-				}
-				swsusp_set_page_free(pfn_to_page(pfn + i));
-			}
-		}
-	}
-	spin_unlock_irqrestore(&zone->lock, flags);
-}
-#endif /* CONFIG_PM */
-
 static bool free_unref_page_prepare(struct page *page, unsigned long pfn,
 							unsigned int order)
 {