+ treewide-remove-migratepage_success.patch added to mm-new branch

[Andrew Morton <akpm@linux-foundation.org>]

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The patch titled
     Subject: treewide: remove MIGRATEPAGE_SUCCESS
has been added to the -mm mm-new branch.  Its filename is
     treewide-remove-migratepage_success.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/treewide-remove-migratepage_success.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: David Hildenbrand <david@redhat.com>
Subject: treewide: remove MIGRATEPAGE_SUCCESS
Date: Mon, 11 Aug 2025 16:39:48 +0200

At this point MIGRATEPAGE_SUCCESS is misnamed for all folio users,
and now that we remove MIGRATEPAGE_UNMAP, it's really the only "success"
return value that the code uses and expects.

Let's just get rid of MIGRATEPAGE_SUCCESS completely and just use "0"
for success.

Link: https://lkml.kernel.org/r/20250811143949.1117439-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>			[mm]
Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com>	[jfs]
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Kleikamp <shaggy@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: Eugenio Pé rez <eperezma@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/powerpc/platforms/pseries/cmm.c |    2 -
 drivers/misc/vmw_balloon.c           |    4 +-
 drivers/virtio/virtio_balloon.c      |    2 -
 fs/aio.c                             |    2 -
 fs/btrfs/inode.c                     |    4 +-
 fs/hugetlbfs/inode.c                 |    4 +-
 fs/jfs/jfs_metapage.c                |    8 ++---
 include/linux/migrate.h              |   10 ------
 mm/migrate.c                         |   40 +++++++++++--------------
 mm/migrate_device.c                  |    2 -
 mm/zsmalloc.c                        |    4 +-
 11 files changed, 36 insertions(+), 46 deletions(-)

--- a/arch/powerpc/platforms/pseries/cmm.c~treewide-remove-migratepage_success
+++ a/arch/powerpc/platforms/pseries/cmm.c
@@ -545,7 +545,7 @@ static int cmm_migratepage(struct balloo
 	/* balloon page list reference */
 	put_page(page);
 
-	return MIGRATEPAGE_SUCCESS;
+	return 0;
 }
 
 static void cmm_balloon_compaction_init(void)
--- a/drivers/misc/vmw_balloon.c~treewide-remove-migratepage_success
+++ a/drivers/misc/vmw_balloon.c
@@ -1806,7 +1806,7 @@ static int vmballoon_migratepage(struct
 		 * the list after acquiring the lock.
 		 */
 		get_page(newpage);
-		ret = MIGRATEPAGE_SUCCESS;
+		ret = 0;
 	}
 
 	/* Update the balloon list under the @pages_lock */
@@ -1817,7 +1817,7 @@ static int vmballoon_migratepage(struct
 	 * If we succeed just insert it to the list and update the statistics
 	 * under the lock.
 	 */
-	if (ret == MIGRATEPAGE_SUCCESS) {
+	if (!ret) {
 		balloon_page_insert(&b->b_dev_info, newpage);
 		__count_vm_event(BALLOON_MIGRATE);
 	}
--- a/drivers/virtio/virtio_balloon.c~treewide-remove-migratepage_success
+++ a/drivers/virtio/virtio_balloon.c
@@ -875,7 +875,7 @@ static int virtballoon_migratepage(struc
 	balloon_page_finalize(page);
 	put_page(page); /* balloon reference */
 
-	return MIGRATEPAGE_SUCCESS;
+	return 0;
 }
 #endif /* CONFIG_BALLOON_COMPACTION */
 
--- a/fs/aio.c~treewide-remove-migratepage_success
+++ a/fs/aio.c
@@ -445,7 +445,7 @@ static int aio_migrate_folio(struct addr
 	folio_get(dst);
 
 	rc = folio_migrate_mapping(mapping, dst, src, 1);
-	if (rc != MIGRATEPAGE_SUCCESS) {
+	if (rc) {
 		folio_put(dst);
 		goto out_unlock;
 	}
--- a/fs/btrfs/inode.c~treewide-remove-migratepage_success
+++ a/fs/btrfs/inode.c
@@ -7411,7 +7411,7 @@ static int btrfs_migrate_folio(struct ad
 {
 	int ret = filemap_migrate_folio(mapping, dst, src, mode);
 
-	if (ret != MIGRATEPAGE_SUCCESS)
+	if (ret)
 		return ret;
 
 	if (folio_test_ordered(src)) {
@@ -7419,7 +7419,7 @@ static int btrfs_migrate_folio(struct ad
 		folio_set_ordered(dst);
 	}
 
-	return MIGRATEPAGE_SUCCESS;
+	return 0;
 }
 #else
 #define btrfs_migrate_folio NULL
--- a/fs/hugetlbfs/inode.c~treewide-remove-migratepage_success
+++ a/fs/hugetlbfs/inode.c
@@ -1052,7 +1052,7 @@ static int hugetlbfs_migrate_folio(struc
 	int rc;
 
 	rc = migrate_huge_page_move_mapping(mapping, dst, src);
-	if (rc != MIGRATEPAGE_SUCCESS)
+	if (rc)
 		return rc;
 
 	if (hugetlb_folio_subpool(src)) {
@@ -1063,7 +1063,7 @@ static int hugetlbfs_migrate_folio(struc
 
 	folio_migrate_flags(dst, src);
 
-	return MIGRATEPAGE_SUCCESS;
+	return 0;
 }
 #else
 #define hugetlbfs_migrate_folio NULL
--- a/fs/jfs/jfs_metapage.c~treewide-remove-migratepage_success
+++ a/fs/jfs/jfs_metapage.c
@@ -169,7 +169,7 @@ static int __metapage_migrate_folio(stru
 	}
 
 	rc = filemap_migrate_folio(mapping, dst, src, mode);
-	if (rc != MIGRATEPAGE_SUCCESS)
+	if (rc)
 		return rc;
 
 	for (i = 0; i < MPS_PER_PAGE; i++) {
@@ -199,7 +199,7 @@ static int __metapage_migrate_folio(stru
 		}
 	}
 
-	return MIGRATEPAGE_SUCCESS;
+	return 0;
 }
 #endif	/* CONFIG_MIGRATION */
 
@@ -242,7 +242,7 @@ static int __metapage_migrate_folio(stru
 		return -EAGAIN;
 
 	rc = filemap_migrate_folio(mapping, dst, src, mode);
-	if (rc != MIGRATEPAGE_SUCCESS)
+	if (rc)
 		return rc;
 
 	if (unlikely(insert_metapage(dst, mp)))
@@ -253,7 +253,7 @@ static int __metapage_migrate_folio(stru
 	mp->folio = dst;
 	remove_metapage(src, mp);
 
-	return MIGRATEPAGE_SUCCESS;
+	return 0;
 }
 #endif	/* CONFIG_MIGRATION */
 
--- a/include/linux/migrate.h~treewide-remove-migratepage_success
+++ a/include/linux/migrate.h
@@ -12,13 +12,6 @@ typedef void free_folio_t(struct folio *
 
 struct migration_target_control;
 
-/*
- * Return values from addresss_space_operations.migratepage():
- * - negative errno on page migration failure;
- * - zero on page migration success;
- */
-#define MIGRATEPAGE_SUCCESS		0
-
 /**
  * struct movable_operations - Driver page migration
  * @isolate_page:
@@ -34,8 +27,7 @@ struct migration_target_control;
  * @src page.  The driver should copy the contents of the
  * @src page to the @dst page and set up the fields of @dst page.
  * Both pages are locked.
- * If page migration is successful, the driver should
- * return MIGRATEPAGE_SUCCESS.
+ * If page migration is successful, the driver should return 0.
  * If the driver cannot migrate the page at the moment, it can return
  * -EAGAIN.  The VM interprets this as a temporary migration failure and
  * will retry it later.  Any other error value is a permanent migration
--- a/mm/migrate.c~treewide-remove-migratepage_success
+++ a/mm/migrate.c
@@ -209,18 +209,17 @@ static void putback_movable_ops_page(str
  * src and dst are also released by migration core. These pages will not be
  * folios in the future, so that must be reworked.
  *
- * Returns MIGRATEPAGE_SUCCESS on success, otherwise a negative error
- * code.
+ * Returns 0 on success, otherwise a negative error code.
  */
 static int migrate_movable_ops_page(struct page *dst, struct page *src,
 		enum migrate_mode mode)
 {
-	int rc = MIGRATEPAGE_SUCCESS;
+	int rc;
 
 	VM_WARN_ON_ONCE_PAGE(!page_has_movable_ops(src), src);
 	VM_WARN_ON_ONCE_PAGE(!PageMovableOpsIsolated(src), src);
 	rc = page_movable_ops(src)->migrate_page(dst, src, mode);
-	if (rc == MIGRATEPAGE_SUCCESS)
+	if (!rc)
 		ClearPageMovableOpsIsolated(src);
 	return rc;
 }
@@ -565,7 +564,7 @@ static int __folio_migrate_mapping(struc
 		if (folio_test_swapbacked(folio))
 			__folio_set_swapbacked(newfolio);
 
-		return MIGRATEPAGE_SUCCESS;
+		return 0;
 	}
 
 	oldzone = folio_zone(folio);
@@ -666,7 +665,7 @@ static int __folio_migrate_mapping(struc
 	}
 	local_irq_enable();
 
-	return MIGRATEPAGE_SUCCESS;
+	return 0;
 }
 
 int folio_migrate_mapping(struct address_space *mapping,
@@ -715,7 +714,7 @@ int migrate_huge_page_move_mapping(struc
 
 	xas_unlock_irq(&xas);
 
-	return MIGRATEPAGE_SUCCESS;
+	return 0;
 }
 
 /*
@@ -831,14 +830,14 @@ static int __migrate_folio(struct addres
 		return rc;
 
 	rc = __folio_migrate_mapping(mapping, dst, src, expected_count);
-	if (rc != MIGRATEPAGE_SUCCESS)
+	if (rc)
 		return rc;
 
 	if (src_private)
 		folio_attach_private(dst, folio_detach_private(src));
 
 	folio_migrate_flags(dst, src);
-	return MIGRATEPAGE_SUCCESS;
+	return 0;
 }
 
 /**
@@ -945,7 +944,7 @@ recheck_buffers:
 	}
 
 	rc = filemap_migrate_folio(mapping, dst, src, mode);
-	if (rc != MIGRATEPAGE_SUCCESS)
+	if (rc)
 		goto unlock_buffers;
 
 	bh = head;
@@ -1049,7 +1048,7 @@ static int fallback_migrate_folio(struct
  *
  * Return value:
  *   < 0 - error code
- *  MIGRATEPAGE_SUCCESS - success
+ *     0 - success
  */
 static int move_to_new_folio(struct folio *dst, struct folio *src,
 				enum migrate_mode mode)
@@ -1077,7 +1076,7 @@ static int move_to_new_folio(struct foli
 	else
 		rc = fallback_migrate_folio(mapping, dst, src, mode);
 
-	if (rc == MIGRATEPAGE_SUCCESS) {
+	if (!rc) {
 		/*
 		 * For pagecache folios, src->mapping must be cleared before src
 		 * is freed. Anonymous folios must stay anonymous until freed.
@@ -1427,7 +1426,7 @@ static int unmap_and_move_huge_page(new_
 	if (folio_ref_count(src) == 1) {
 		/* page was freed from under us. So we are done. */
 		folio_putback_hugetlb(src);
-		return MIGRATEPAGE_SUCCESS;
+		return 0;
 	}
 
 	dst = get_new_folio(src, private);
@@ -1490,8 +1489,7 @@ static int unmap_and_move_huge_page(new_
 		rc = move_to_new_folio(dst, src, mode);
 
 	if (page_was_mapped)
-		remove_migration_ptes(src,
-			rc == MIGRATEPAGE_SUCCESS ? dst : src, 0);
+		remove_migration_ptes(src, !rc ? dst : src, 0);
 
 unlock_put_anon:
 	folio_unlock(dst);
@@ -1500,7 +1498,7 @@ put_anon:
 	if (anon_vma)
 		put_anon_vma(anon_vma);
 
-	if (rc == MIGRATEPAGE_SUCCESS) {
+	if (!rc) {
 		move_hugetlb_state(src, dst, reason);
 		put_new_folio = NULL;
 	}
@@ -1508,7 +1506,7 @@ put_anon:
 out_unlock:
 	folio_unlock(src);
 out:
-	if (rc == MIGRATEPAGE_SUCCESS)
+	if (!rc)
 		folio_putback_hugetlb(src);
 	else if (rc != -EAGAIN)
 		list_move_tail(&src->lru, ret);
@@ -1618,7 +1616,7 @@ static int migrate_hugetlbs(struct list_
 						      reason, ret_folios);
 			/*
 			 * The rules are:
-			 *	Success: hugetlb folio will be put back
+			 *	0: hugetlb folio will be put back
 			 *	-EAGAIN: stay on the from list
 			 *	-ENOMEM: stay on the from list
 			 *	Other errno: put on ret_folios list
@@ -1635,7 +1633,7 @@ static int migrate_hugetlbs(struct list_
 				retry++;
 				nr_retry_pages += nr_pages;
 				break;
-			case MIGRATEPAGE_SUCCESS:
+			case 0:
 				stats->nr_succeeded += nr_pages;
 				break;
 			default:
@@ -1689,7 +1687,7 @@ static void migrate_folios_move(struct l
 				reason, ret_folios);
 		/*
 		 * The rules are:
-		 *	Success: folio will be freed
+		 *	0: folio will be freed
 		 *	-EAGAIN: stay on the unmap_folios list
 		 *	Other errno: put on ret_folios list
 		 */
@@ -1699,7 +1697,7 @@ static void migrate_folios_move(struct l
 			*thp_retry += is_thp;
 			*nr_retry_pages += nr_pages;
 			break;
-		case MIGRATEPAGE_SUCCESS:
+		case 0:
 			stats->nr_succeeded += nr_pages;
 			stats->nr_thp_succeeded += is_thp;
 			break;
--- a/mm/migrate_device.c~treewide-remove-migratepage_success
+++ a/mm/migrate_device.c
@@ -778,7 +778,7 @@ static void __migrate_device_pages(unsig
 		if (migrate && migrate->fault_page == page)
 			extra_cnt = 1;
 		r = folio_migrate_mapping(mapping, newfolio, folio, extra_cnt);
-		if (r != MIGRATEPAGE_SUCCESS)
+		if (r)
 			src_pfns[i] &= ~MIGRATE_PFN_MIGRATE;
 		else
 			folio_migrate_flags(newfolio, folio);
--- a/mm/zsmalloc.c~treewide-remove-migratepage_success
+++ a/mm/zsmalloc.c
@@ -1746,7 +1746,7 @@ static int zs_page_migrate(struct page *
 	 * instead.
 	 */
 	if (!zpdesc->zspage)
-		return MIGRATEPAGE_SUCCESS;
+		return 0;
 
 	/* The page is locked, so this pointer must remain valid */
 	zspage = get_zspage(zpdesc);
@@ -1813,7 +1813,7 @@ static int zs_page_migrate(struct page *
 	reset_zpdesc(zpdesc);
 	zpdesc_put(zpdesc);
 
-	return MIGRATEPAGE_SUCCESS;
+	return 0;
 }
 
 static void zs_page_putback(struct page *page)
_

Patches currently in -mm which might be from david@redhat.com are

mm-migrate-remove-migratepage_unmap.patch
treewide-remove-migratepage_success.patch