[PATCH 00/20] Convert aops->migratepage to aops->migrate_folio

[PATCH 00/20] Convert aops->migratepage to aops->migrate_folio

[Matthew Wilcox (Oracle)]

I plan to submit these patches through my pagecache tree in the upcoming
merge window.  I'm pretty happy that most filesystems are now using
common code for ->migrate_folio; it's not something that most filesystem
people want to care about.  I'm running xfstests using xfs against it now,
but it's little more than compile tested for other filesystems.

Matthew Wilcox (Oracle) (20):
  fs: Add aops->migrate_folio
  mm/migrate: Convert fallback_migrate_page() to
    fallback_migrate_folio()
  mm/migrate: Convert writeout() to take a folio
  mm/migrate: Convert buffer_migrate_page() to buffer_migrate_folio()
  mm/migrate: Convert expected_page_refs() to folio_expected_refs()
  btrfs: Convert btree_migratepage to migrate_folio
  nfs: Convert to migrate_folio
  mm/migrate: Convert migrate_page() to migrate_folio()
  mm/migrate: Add filemap_migrate_folio()
  btrfs: Convert btrfs_migratepage to migrate_folio
  ubifs: Convert to filemap_migrate_folio()
  f2fs: Convert to filemap_migrate_folio()
  aio: Convert to migrate_folio
  hugetlb: Convert to migrate_folio
  balloon: Convert to migrate_folio
  secretmem: Convert to migrate_folio
  z3fold: Convert to migrate_folio
  zsmalloc: Convert to migrate_folio
  fs: Remove aops->migratepage()
  mm/folio-compat: Remove migration compatibility functions

 Documentation/filesystems/locking.rst       |   5 +-
 Documentation/filesystems/vfs.rst           |  13 +-
 Documentation/vm/page_migration.rst         |  33 +--
 block/fops.c                                |   2 +-
 drivers/gpu/drm/i915/gem/i915_gem_userptr.c |   4 +-
 fs/aio.c                                    |  36 ++--
 fs/btrfs/disk-io.c                          |  22 +-
 fs/btrfs/inode.c                            |  26 +--
 fs/ext2/inode.c                             |   4 +-
 fs/ext4/inode.c                             |   4 +-
 fs/f2fs/checkpoint.c                        |   4 +-
 fs/f2fs/data.c                              |  40 +---
 fs/f2fs/f2fs.h                              |   4 -
 fs/f2fs/node.c                              |   4 +-
 fs/gfs2/aops.c                              |   2 +-
 fs/hugetlbfs/inode.c                        |  19 +-
 fs/iomap/buffered-io.c                      |  25 ---
 fs/nfs/file.c                               |   4 +-
 fs/nfs/internal.h                           |   6 +-
 fs/nfs/write.c                              |  16 +-
 fs/ntfs/aops.c                              |   6 +-
 fs/ocfs2/aops.c                             |   2 +-
 fs/ubifs/file.c                             |  29 +--
 fs/xfs/xfs_aops.c                           |   2 +-
 fs/zonefs/super.c                           |   2 +-
 include/linux/buffer_head.h                 |  10 +
 include/linux/fs.h                          |  18 +-
 include/linux/iomap.h                       |   6 -
 include/linux/migrate.h                     |  22 +-
 include/linux/pagemap.h                     |   6 +
 mm/balloon_compaction.c                     |  15 +-
 mm/compaction.c                             |   5 +-
 mm/folio-compat.c                           |  22 --
 mm/ksm.c                                    |   2 +-
 mm/migrate.c                                | 217 ++++++++++++--------
 mm/migrate_device.c                         |   3 +-
 mm/secretmem.c                              |   6 +-
 mm/shmem.c                                  |   2 +-
 mm/swap_state.c                             |   2 +-
 mm/z3fold.c                                 |   8 +-
 mm/zsmalloc.c                               |   8 +-
 41 files changed, 287 insertions(+), 379 deletions(-)

-- 
2.35.1


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[PATCH 01/20] fs: Add aops->migrate_folio

[Matthew Wilcox (Oracle)]

Provide a folio-based replacement for aops->migratepage.  Update the
documentation to document migrate_folio instead of migratepage.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 Documentation/filesystems/locking.rst |  5 ++--
 Documentation/filesystems/vfs.rst     | 13 ++++++-----
 Documentation/vm/page_migration.rst   | 33 ++++++++++++++-------------
 include/linux/fs.h                    |  4 +++-
 mm/compaction.c                       |  4 +++-
 mm/migrate.c                          | 19 ++++++++++-----
 6 files changed, 46 insertions(+), 32 deletions(-)

diff --git a/Documentation/filesystems/locking.rst b/Documentation/filesystems/locking.rst
index c0fe711f14d3..3d28b23676bd 100644
--- a/Documentation/filesystems/locking.rst
+++ b/Documentation/filesystems/locking.rst
@@ -253,7 +253,8 @@ prototypes::
 	void (*free_folio)(struct folio *);
 	int (*direct_IO)(struct kiocb *, struct iov_iter *iter);
 	bool (*isolate_page) (struct page *, isolate_mode_t);
-	int (*migratepage)(struct address_space *, struct page *, struct page *);
+	int (*migrate_folio)(struct address_space *, struct folio *dst,
+			struct folio *src, enum migrate_mode);
 	void (*putback_page) (struct page *);
 	int (*launder_folio)(struct folio *);
 	bool (*is_partially_uptodate)(struct folio *, size_t from, size_t count);
@@ -281,7 +282,7 @@ release_folio:		yes
 free_folio:		yes
 direct_IO:
 isolate_page:		yes
-migratepage:		yes (both)
+migrate_folio:		yes (both)
 putback_page:		yes
 launder_folio:		yes
 is_partially_uptodate:	yes
diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst
index a08c652467d7..3ae1b039b03f 100644
--- a/Documentation/filesystems/vfs.rst
+++ b/Documentation/filesystems/vfs.rst
@@ -740,7 +740,8 @@ cache in your filesystem.  The following members are defined:
 		/* isolate a page for migration */
 		bool (*isolate_page) (struct page *, isolate_mode_t);
 		/* migrate the contents of a page to the specified target */
-		int (*migratepage) (struct page *, struct page *);
+		int (*migrate_folio)(struct mapping *, struct folio *dst,
+				struct folio *src, enum migrate_mode);
 		/* put migration-failed page back to right list */
 		void (*putback_page) (struct page *);
 		int (*launder_folio) (struct folio *);
@@ -935,12 +936,12 @@ cache in your filesystem.  The following members are defined:
 	is successfully isolated, VM marks the page as PG_isolated via
 	__SetPageIsolated.
 
-``migrate_page``
+``migrate_folio``
 	This is used to compact the physical memory usage.  If the VM
-	wants to relocate a page (maybe off a memory card that is
-	signalling imminent failure) it will pass a new page and an old
-	page to this function.  migrate_page should transfer any private
-	data across and update any references that it has to the page.
+	wants to relocate a folio (maybe from a memory device that is
+	signalling imminent failure) it will pass a new folio and an old
+	folio to this function.  migrate_folio should transfer any private
+	data across and update any references that it has to the folio.
 
 ``putback_page``
 	Called by the VM when isolated page's migration fails.
diff --git a/Documentation/vm/page_migration.rst b/Documentation/vm/page_migration.rst
index 8c5cb8147e55..e0f73ddfabb1 100644
--- a/Documentation/vm/page_migration.rst
+++ b/Documentation/vm/page_migration.rst
@@ -181,22 +181,23 @@ which are function pointers of struct address_space_operations.
    Once page is successfully isolated, VM uses page.lru fields so driver
    shouldn't expect to preserve values in those fields.
 
-2. ``int (*migratepage) (struct address_space *mapping,``
-|	``struct page *newpage, struct page *oldpage, enum migrate_mode);``
-
-   After isolation, VM calls migratepage() of driver with the isolated page.
-   The function of migratepage() is to move the contents of the old page to the
-   new page
-   and set up fields of struct page newpage. Keep in mind that you should
-   indicate to the VM the oldpage is no longer movable via __ClearPageMovable()
-   under page_lock if you migrated the oldpage successfully and returned
-   MIGRATEPAGE_SUCCESS. If driver cannot migrate the page at the moment, driver
-   can return -EAGAIN. On -EAGAIN, VM will retry page migration in a short time
-   because VM interprets -EAGAIN as "temporary migration failure". On returning
-   any error except -EAGAIN, VM will give up the page migration without
-   retrying.
-
-   Driver shouldn't touch the page.lru field while in the migratepage() function.
+2. ``int (*migrate_folio) (struct address_space *mapping,``
+|	``struct folio *dst, struct folio *src, enum migrate_mode);``
+
+   After isolation, VM calls the driver's migrate_folio() with the
+   isolated folio.  The purpose of migrate_folio() is to move the contents
+   of the source folio to the destination folio and set up the fields
+   of destination folio.  Keep in mind that you should indicate to the
+   VM the source folio is no longer movable via __ClearPageMovable()
+   under folio if you migrated the source successfully and returned
+   MIGRATEPAGE_SUCCESS.  If driver cannot migrate the folio at the
+   moment, driver can return -EAGAIN. On -EAGAIN, VM will retry folio
+   migration in a short time because VM interprets -EAGAIN as "temporary
+   migration failure".  On returning any error except -EAGAIN, VM will
+   give up the folio migration without retrying.
+
+   Driver shouldn't touch the folio.lru field while in the migrate_folio()
+   function.
 
 3. ``void (*putback_page)(struct page *);``
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 9ad5e3520fae..7b380fa66983 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -362,9 +362,11 @@ struct address_space_operations {
 	void (*free_folio)(struct folio *folio);
 	ssize_t (*direct_IO)(struct kiocb *, struct iov_iter *iter);
 	/*
-	 * migrate the contents of a page to the specified target. If
+	 * migrate the contents of a folio to the specified target. If
 	 * migrate_mode is MIGRATE_ASYNC, it must not block.
 	 */
+	int (*migrate_folio)(struct address_space *, struct folio *dst,
+			struct folio *src, enum migrate_mode);
 	int (*migratepage) (struct address_space *,
 			struct page *, struct page *, enum migrate_mode);
 	bool (*isolate_page)(struct page *, isolate_mode_t);
diff --git a/mm/compaction.c b/mm/compaction.c
index 1f89b969c12b..db34b459e5d9 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1045,7 +1045,9 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 				goto isolate_fail_put;
 
 			mapping = page_mapping(page);
-			migrate_dirty = !mapping || mapping->a_ops->migratepage;
+			migrate_dirty = !mapping ||
+					mapping->a_ops->migrate_folio ||
+					mapping->a_ops->migratepage;
 			unlock_page(page);
 			if (!migrate_dirty)
 				goto isolate_fail_put;
diff --git a/mm/migrate.c b/mm/migrate.c
index e51588e95f57..75cb6aa38988 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -858,14 +858,17 @@ static int move_to_new_folio(struct folio *dst, struct folio *src,
 	if (likely(is_lru)) {
 		if (!mapping)
 			rc = migrate_page(mapping, &dst->page, &src->page, mode);
-		else if (mapping->a_ops->migratepage)
+		else if (mapping->a_ops->migrate_folio)
 			/*
-			 * Most pages have a mapping and most filesystems
-			 * provide a migratepage callback. Anonymous pages
+			 * Most folios have a mapping and most filesystems
+			 * provide a migrate_folio callback. Anonymous folios
 			 * are part of swap space which also has its own
-			 * migratepage callback. This is the most common path
+			 * migrate_folio callback. This is the most common path
 			 * for page migration.
 			 */
+			rc = mapping->a_ops->migrate_folio(mapping, dst, src,
+								mode);
+		else if (mapping->a_ops->migratepage)
 			rc = mapping->a_ops->migratepage(mapping, &dst->page,
 							&src->page, mode);
 		else
@@ -883,8 +886,12 @@ static int move_to_new_folio(struct folio *dst, struct folio *src,
 			goto out;
 		}
 
-		rc = mapping->a_ops->migratepage(mapping, &dst->page,
-						&src->page, mode);
+		if (mapping->a_ops->migrate_folio)
+			rc = mapping->a_ops->migrate_folio(mapping, dst, src,
+								mode);
+		else
+			rc = mapping->a_ops->migratepage(mapping, &dst->page,
+							&src->page, mode);
 		WARN_ON_ONCE(rc == MIGRATEPAGE_SUCCESS &&
 				!folio_test_isolated(src));
 	}
-- 
2.35.1


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Re: [PATCH 01/20] fs: Add aops->migrate_folio

[Christoph Hellwig]

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

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[PATCH 02/20] mm/migrate: Convert fallback_migrate_page() to fallback_migrate_folio()

[Matthew Wilcox (Oracle)]

Use a folio throughout.  migrate_page() will be converted to
migrate_folio() later.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/migrate.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index 75cb6aa38988..d772ce63d7e2 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -806,11 +806,11 @@ static int writeout(struct address_space *mapping, struct page *page)
 /*
  * Default handling if a filesystem does not provide a migration function.
  */
-static int fallback_migrate_page(struct address_space *mapping,
-	struct page *newpage, struct page *page, enum migrate_mode mode)
+static int fallback_migrate_folio(struct address_space *mapping,
+		struct folio *dst, struct folio *src, enum migrate_mode mode)
 {
-	if (PageDirty(page)) {
-		/* Only writeback pages in full synchronous migration */
+	if (folio_test_dirty(src)) {
+		/* Only writeback folios in full synchronous migration */
 		switch (mode) {
 		case MIGRATE_SYNC:
 		case MIGRATE_SYNC_NO_COPY:
@@ -818,18 +818,18 @@ static int fallback_migrate_page(struct address_space *mapping,
 		default:
 			return -EBUSY;
 		}
-		return writeout(mapping, page);
+		return writeout(mapping, &src->page);
 	}
 
 	/*
 	 * Buffers may be managed in a filesystem specific way.
 	 * We must have no buffers or drop them.
 	 */
-	if (page_has_private(page) &&
-	    !try_to_release_page(page, GFP_KERNEL))
+	if (folio_test_private(src) &&
+	    !filemap_release_folio(src, GFP_KERNEL))
 		return mode == MIGRATE_SYNC ? -EAGAIN : -EBUSY;
 
-	return migrate_page(mapping, newpage, page, mode);
+	return migrate_page(mapping, &dst->page, &src->page, mode);
 }
 
 /*
@@ -872,8 +872,7 @@ static int move_to_new_folio(struct folio *dst, struct folio *src,
 			rc = mapping->a_ops->migratepage(mapping, &dst->page,
 							&src->page, mode);
 		else
-			rc = fallback_migrate_page(mapping, &dst->page,
-							&src->page, mode);
+			rc = fallback_migrate_folio(mapping, dst, src, mode);
 	} else {
 		/*
 		 * In case of non-lru page, it could be released after
-- 
2.35.1


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Re: [PATCH 02/20] mm/migrate: Convert fallback_migrate_page() to fallback_migrate_folio()

[Christoph Hellwig]

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

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[PATCH 03/20] mm/migrate: Convert writeout() to take a folio

[Matthew Wilcox (Oracle)]

Use a folio throughout this function.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/migrate.c | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index d772ce63d7e2..f19246c12fe9 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -762,11 +762,10 @@ int buffer_migrate_page_norefs(struct address_space *mapping,
 #endif
 
 /*
- * Writeback a page to clean the dirty state
+ * Writeback a folio to clean the dirty state
  */
-static int writeout(struct address_space *mapping, struct page *page)
+static int writeout(struct address_space *mapping, struct folio *folio)
 {
-	struct folio *folio = page_folio(page);
 	struct writeback_control wbc = {
 		.sync_mode = WB_SYNC_NONE,
 		.nr_to_write = 1,
@@ -780,25 +779,25 @@ static int writeout(struct address_space *mapping, struct page *page)
 		/* No write method for the address space */
 		return -EINVAL;
 
-	if (!clear_page_dirty_for_io(page))
+	if (!folio_clear_dirty_for_io(folio))
 		/* Someone else already triggered a write */
 		return -EAGAIN;
 
 	/*
-	 * A dirty page may imply that the underlying filesystem has
-	 * the page on some queue. So the page must be clean for
-	 * migration. Writeout may mean we loose the lock and the
-	 * page state is no longer what we checked for earlier.
+	 * A dirty folio may imply that the underlying filesystem has
+	 * the folio on some queue. So the folio must be clean for
+	 * migration. Writeout may mean we lose the lock and the
+	 * folio state is no longer what we checked for earlier.
 	 * At this point we know that the migration attempt cannot
 	 * be successful.
 	 */
 	remove_migration_ptes(folio, folio, false);
 
-	rc = mapping->a_ops->writepage(page, &wbc);
+	rc = mapping->a_ops->writepage(&folio->page, &wbc);
 
 	if (rc != AOP_WRITEPAGE_ACTIVATE)
 		/* unlocked. Relock */
-		lock_page(page);
+		folio_lock(folio);
 
 	return (rc < 0) ? -EIO : -EAGAIN;
 }
@@ -818,7 +817,7 @@ static int fallback_migrate_folio(struct address_space *mapping,
 		default:
 			return -EBUSY;
 		}
-		return writeout(mapping, &src->page);
+		return writeout(mapping, src);
 	}
 
 	/*
-- 
2.35.1


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Re: [PATCH 03/20] mm/migrate: Convert writeout() to take a folio

[Christoph Hellwig]

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>


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[PATCH 04/20] mm/migrate: Convert buffer_migrate_page() to buffer_migrate_folio()

[Matthew Wilcox (Oracle)]

Use a folio throughout __buffer_migrate_folio(), add kernel-doc for
buffer_migrate_folio() and buffer_migrate_folio_norefs(), move their
declarations to buffer.h and switch all filesystems that have wired
them up.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 block/fops.c                |  2 +-
 fs/ext2/inode.c             |  4 +-
 fs/ext4/inode.c             |  4 +-
 fs/ntfs/aops.c              |  6 +--
 fs/ocfs2/aops.c             |  2 +-
 include/linux/buffer_head.h | 10 +++++
 include/linux/fs.h          | 12 ------
 mm/migrate.c                | 76 ++++++++++++++++++++++---------------
 8 files changed, 65 insertions(+), 51 deletions(-)

diff --git a/block/fops.c b/block/fops.c
index d6b3276a6c68..743fc46d0aad 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -417,7 +417,7 @@ const struct address_space_operations def_blk_aops = {
 	.write_end	= blkdev_write_end,
 	.writepages	= blkdev_writepages,
 	.direct_IO	= blkdev_direct_IO,
-	.migratepage	= buffer_migrate_page_norefs,
+	.migrate_folio	= buffer_migrate_folio_norefs,
 	.is_dirty_writeback = buffer_check_dirty_writeback,
 };
 
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 360ce3604a2d..84570c6265aa 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -973,7 +973,7 @@ const struct address_space_operations ext2_aops = {
 	.bmap			= ext2_bmap,
 	.direct_IO		= ext2_direct_IO,
 	.writepages		= ext2_writepages,
-	.migratepage		= buffer_migrate_page,
+	.migrate_folio		= buffer_migrate_folio,
 	.is_partially_uptodate	= block_is_partially_uptodate,
 	.error_remove_page	= generic_error_remove_page,
 };
@@ -989,7 +989,7 @@ const struct address_space_operations ext2_nobh_aops = {
 	.bmap			= ext2_bmap,
 	.direct_IO		= ext2_direct_IO,
 	.writepages		= ext2_writepages,
-	.migratepage		= buffer_migrate_page,
+	.migrate_folio		= buffer_migrate_folio,
 	.error_remove_page	= generic_error_remove_page,
 };
 
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 1aaea53e67b5..53877ffe3c41 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3633,7 +3633,7 @@ static const struct address_space_operations ext4_aops = {
 	.invalidate_folio	= ext4_invalidate_folio,
 	.release_folio		= ext4_release_folio,
 	.direct_IO		= noop_direct_IO,
-	.migratepage		= buffer_migrate_page,
+	.migrate_folio		= buffer_migrate_folio,
 	.is_partially_uptodate  = block_is_partially_uptodate,
 	.error_remove_page	= generic_error_remove_page,
 	.swap_activate		= ext4_iomap_swap_activate,
@@ -3668,7 +3668,7 @@ static const struct address_space_operations ext4_da_aops = {
 	.invalidate_folio	= ext4_invalidate_folio,
 	.release_folio		= ext4_release_folio,
 	.direct_IO		= noop_direct_IO,
-	.migratepage		= buffer_migrate_page,
+	.migrate_folio		= buffer_migrate_folio,
 	.is_partially_uptodate  = block_is_partially_uptodate,
 	.error_remove_page	= generic_error_remove_page,
 	.swap_activate		= ext4_iomap_swap_activate,
diff --git a/fs/ntfs/aops.c b/fs/ntfs/aops.c
index 9e3964ea2ea0..5f4fb6ca6f2e 100644
--- a/fs/ntfs/aops.c
+++ b/fs/ntfs/aops.c
@@ -1659,7 +1659,7 @@ const struct address_space_operations ntfs_normal_aops = {
 	.dirty_folio	= block_dirty_folio,
 #endif /* NTFS_RW */
 	.bmap		= ntfs_bmap,
-	.migratepage	= buffer_migrate_page,
+	.migrate_folio	= buffer_migrate_folio,
 	.is_partially_uptodate = block_is_partially_uptodate,
 	.error_remove_page = generic_error_remove_page,
 };
@@ -1673,7 +1673,7 @@ const struct address_space_operations ntfs_compressed_aops = {
 	.writepage	= ntfs_writepage,
 	.dirty_folio	= block_dirty_folio,
 #endif /* NTFS_RW */
-	.migratepage	= buffer_migrate_page,
+	.migrate_folio	= buffer_migrate_folio,
 	.is_partially_uptodate = block_is_partially_uptodate,
 	.error_remove_page = generic_error_remove_page,
 };
@@ -1688,7 +1688,7 @@ const struct address_space_operations ntfs_mst_aops = {
 	.writepage	= ntfs_writepage,	/* Write dirty page to disk. */
 	.dirty_folio	= filemap_dirty_folio,
 #endif /* NTFS_RW */
-	.migratepage	= buffer_migrate_page,
+	.migrate_folio	= buffer_migrate_folio,
 	.is_partially_uptodate	= block_is_partially_uptodate,
 	.error_remove_page = generic_error_remove_page,
 };
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 767df51f8657..1d489003f99d 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -2462,7 +2462,7 @@ const struct address_space_operations ocfs2_aops = {
 	.direct_IO		= ocfs2_direct_IO,
 	.invalidate_folio	= block_invalidate_folio,
 	.release_folio		= ocfs2_release_folio,
-	.migratepage		= buffer_migrate_page,
+	.migrate_folio		= buffer_migrate_folio,
 	.is_partially_uptodate	= block_is_partially_uptodate,
 	.error_remove_page	= generic_error_remove_page,
 };
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index c9d1463bb20f..b0366c89d6a4 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -267,6 +267,16 @@ int nobh_truncate_page(struct address_space *, loff_t, get_block_t *);
 int nobh_writepage(struct page *page, get_block_t *get_block,
                         struct writeback_control *wbc);
 
+#ifdef CONFIG_MIGRATION
+extern int buffer_migrate_folio(struct address_space *,
+		struct folio *dst, struct folio *src, enum migrate_mode);
+extern int buffer_migrate_folio_norefs(struct address_space *,
+		struct folio *dst, struct folio *src, enum migrate_mode);
+#else
+#define buffer_migrate_folio NULL
+#define buffer_migrate_folio_norefs NULL
+#endif
+
 void buffer_init(void);
 
 /*
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 7b380fa66983..5737c92ed286 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3217,18 +3217,6 @@ extern int generic_check_addressable(unsigned, u64);
 
 extern void generic_set_encrypted_ci_d_ops(struct dentry *dentry);
 
-#ifdef CONFIG_MIGRATION
-extern int buffer_migrate_page(struct address_space *,
-				struct page *, struct page *,
-				enum migrate_mode);
-extern int buffer_migrate_page_norefs(struct address_space *,
-				struct page *, struct page *,
-				enum migrate_mode);
-#else
-#define buffer_migrate_page NULL
-#define buffer_migrate_page_norefs NULL
-#endif
-
 int may_setattr(struct user_namespace *mnt_userns, struct inode *inode,
 		unsigned int ia_valid);
 int setattr_prepare(struct user_namespace *, struct dentry *, struct iattr *);
diff --git a/mm/migrate.c b/mm/migrate.c
index f19246c12fe9..77b8c662c9ca 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -657,23 +657,23 @@ static bool buffer_migrate_lock_buffers(struct buffer_head *head,
 	return true;
 }
 
-static int __buffer_migrate_page(struct address_space *mapping,
-		struct page *newpage, struct page *page, enum migrate_mode mode,
+static int __buffer_migrate_folio(struct address_space *mapping,
+		struct folio *dst, struct folio *src, enum migrate_mode mode,
 		bool check_refs)
 {
 	struct buffer_head *bh, *head;
 	int rc;
 	int expected_count;
 
-	if (!page_has_buffers(page))
-		return migrate_page(mapping, newpage, page, mode);
+	head = folio_buffers(src);
+	if (!head)
+		return migrate_page(mapping, &dst->page, &src->page, mode);
 
 	/* Check whether page does not have extra refs before we do more work */
-	expected_count = expected_page_refs(mapping, page);
-	if (page_count(page) != expected_count)
+	expected_count = expected_page_refs(mapping, &src->page);
+	if (folio_ref_count(src) != expected_count)
 		return -EAGAIN;
 
-	head = page_buffers(page);
 	if (!buffer_migrate_lock_buffers(head, mode))
 		return -EAGAIN;
 
@@ -704,23 +704,22 @@ static int __buffer_migrate_page(struct address_space *mapping,
 		}
 	}
 
-	rc = migrate_page_move_mapping(mapping, newpage, page, 0);
+	rc = folio_migrate_mapping(mapping, dst, src, 0);
 	if (rc != MIGRATEPAGE_SUCCESS)
 		goto unlock_buffers;
 
-	attach_page_private(newpage, detach_page_private(page));
+	folio_attach_private(dst, folio_detach_private(src));
 
 	bh = head;
 	do {
-		set_bh_page(bh, newpage, bh_offset(bh));
+		set_bh_page(bh, &dst->page, bh_offset(bh));
 		bh = bh->b_this_page;
-
 	} while (bh != head);
 
 	if (mode != MIGRATE_SYNC_NO_COPY)
-		migrate_page_copy(newpage, page);
+		folio_migrate_copy(dst, src);
 	else
-		migrate_page_states(newpage, page);
+		folio_migrate_flags(dst, src);
 
 	rc = MIGRATEPAGE_SUCCESS;
 unlock_buffers:
@@ -730,34 +729,51 @@ static int __buffer_migrate_page(struct address_space *mapping,
 	do {
 		unlock_buffer(bh);
 		bh = bh->b_this_page;
-
 	} while (bh != head);
 
 	return rc;
 }
 
-/*
- * Migration function for pages with buffers. This function can only be used
- * if the underlying filesystem guarantees that no other references to "page"
- * exist. For example attached buffer heads are accessed only under page lock.
+/**
+ * buffer_migrate_folio() - Migration function for folios with buffers.
+ * @mapping: The address space containing @src.
+ * @dst: The folio to migrate to.
+ * @src: The folio to migrate from.
+ * @mode: How to migrate the folio.
+ *
+ * This function can only be used if the underlying filesystem guarantees
+ * that no other references to @src exist. For example attached buffer
+ * heads are accessed only under the folio lock.  If your filesystem cannot
+ * provide this guarantee, buffer_migrate_folio_noref() may be more
+ * appropriate.
+ *
+ * Return: 0 on success or a negative errno on failure.
  */
-int buffer_migrate_page(struct address_space *mapping,
-		struct page *newpage, struct page *page, enum migrate_mode mode)
+int buffer_migrate_folio(struct address_space *mapping,
+		struct folio *dst, struct folio *src, enum migrate_mode mode)
 {
-	return __buffer_migrate_page(mapping, newpage, page, mode, false);
+	return __buffer_migrate_folio(mapping, dst, src, mode, false);
 }
-EXPORT_SYMBOL(buffer_migrate_page);
+EXPORT_SYMBOL(buffer_migrate_folio);
 
-/*
- * Same as above except that this variant is more careful and checks that there
- * are also no buffer head references. This function is the right one for
- * mappings where buffer heads are directly looked up and referenced (such as
- * block device mappings).
+/**
+ * buffer_migrate_folio_noref() - Migration function for folios with buffers.
+ * @mapping: The address space containing @src.
+ * @dst: The folio to migrate to.
+ * @src: The folio to migrate from.
+ * @mode: How to migrate the folio.
+ *
+ * Like buffer_migrate_folio() except that this variant is more careful
+ * and checks that there are also no buffer head references. This function
+ * is the right one for mappings where buffer heads are directly looked
+ * up and referenced (such as block device mappings).
+ *
+ * Return: 0 on success or a negative errno on failure.
  */
-int buffer_migrate_page_norefs(struct address_space *mapping,
-		struct page *newpage, struct page *page, enum migrate_mode mode)
+int buffer_migrate_folio_norefs(struct address_space *mapping,
+		struct folio *dst, struct folio *src, enum migrate_mode mode)
 {
-	return __buffer_migrate_page(mapping, newpage, page, mode, true);
+	return __buffer_migrate_folio(mapping, dst, src, mode, true);
 }
 #endif
 
-- 
2.35.1


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Re: [PATCH 04/20] mm/migrate: Convert buffer_migrate_page() to buffer_migrate_folio()

[kernel test robot]

Hi "Matthew,

I love your patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v5.19-rc1 next-20220606]
[cannot apply to jaegeuk-f2fs/dev-test trondmy-nfs/linux-next kdave/for-next xfs-linux/for-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/intel-lab-lkp/linux/commits/Matthew-Wilcox-Oracle/Convert-aops-migratepage-to-aops-migrate_folio/20220607-044509
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git f2906aa863381afb0015a9eb7fefad885d4e5a56
config: i386-defconfig (https://download.01.org/0day-ci/archive/20220607/202206071139.aWSx4GHH-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-1) 11.3.0
reproduce (this is a W=1 build):
        # https://github.com/intel-lab-lkp/linux/commit/96e64ba8b1be545885d89f44b1d8b968b22bdb4d
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Matthew-Wilcox-Oracle/Convert-aops-migratepage-to-aops-migrate_folio/20220607-044509
        git checkout 96e64ba8b1be545885d89f44b1d8b968b22bdb4d
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> mm/migrate.c:775: warning: expecting prototype for buffer_migrate_folio_noref(). Prototype was for buffer_migrate_folio_norefs() instead


vim +775 mm/migrate.c

89cb0888ca1483a Jan Kara                2018-12-28  758  
96e64ba8b1be545 Matthew Wilcox (Oracle  2022-06-06  759) /**
96e64ba8b1be545 Matthew Wilcox (Oracle  2022-06-06  760)  * buffer_migrate_folio_noref() - Migration function for folios with buffers.
96e64ba8b1be545 Matthew Wilcox (Oracle  2022-06-06  761)  * @mapping: The address space containing @src.
96e64ba8b1be545 Matthew Wilcox (Oracle  2022-06-06  762)  * @dst: The folio to migrate to.
96e64ba8b1be545 Matthew Wilcox (Oracle  2022-06-06  763)  * @src: The folio to migrate from.
96e64ba8b1be545 Matthew Wilcox (Oracle  2022-06-06  764)  * @mode: How to migrate the folio.
96e64ba8b1be545 Matthew Wilcox (Oracle  2022-06-06  765)  *
96e64ba8b1be545 Matthew Wilcox (Oracle  2022-06-06  766)  * Like buffer_migrate_folio() except that this variant is more careful
96e64ba8b1be545 Matthew Wilcox (Oracle  2022-06-06  767)  * and checks that there are also no buffer head references. This function
96e64ba8b1be545 Matthew Wilcox (Oracle  2022-06-06  768)  * is the right one for mappings where buffer heads are directly looked
96e64ba8b1be545 Matthew Wilcox (Oracle  2022-06-06  769)  * up and referenced (such as block device mappings).
96e64ba8b1be545 Matthew Wilcox (Oracle  2022-06-06  770)  *
96e64ba8b1be545 Matthew Wilcox (Oracle  2022-06-06  771)  * Return: 0 on success or a negative errno on failure.
89cb0888ca1483a Jan Kara                2018-12-28  772   */
96e64ba8b1be545 Matthew Wilcox (Oracle  2022-06-06  773) int buffer_migrate_folio_norefs(struct address_space *mapping,
96e64ba8b1be545 Matthew Wilcox (Oracle  2022-06-06  774) 		struct folio *dst, struct folio *src, enum migrate_mode mode)
89cb0888ca1483a Jan Kara                2018-12-28 @775  {
96e64ba8b1be545 Matthew Wilcox (Oracle  2022-06-06  776) 	return __buffer_migrate_folio(mapping, dst, src, mode, true);
89cb0888ca1483a Jan Kara                2018-12-28  777  }
9361401eb7619c0 David Howells           2006-09-30  778  #endif
1d8b85ccf1ed53a Christoph Lameter       2006-06-23  779  

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Re: [PATCH 04/20] mm/migrate: Convert buffer_migrate_page() to buffer_migrate_folio()

[Matthew Wilcox]

On Tue, Jun 07, 2022 at 11:37:45AM +0800, kernel test robot wrote:
> All warnings (new ones prefixed by >>):
> 
> >> mm/migrate.c:775: warning: expecting prototype for buffer_migrate_folio_noref(). Prototype was for buffer_migrate_folio_norefs() instead

No good deed (turning documentation into kerneldoc) goes unpunished ...
thanks, fixed.

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Re: [PATCH 04/20] mm/migrate: Convert buffer_migrate_page() to buffer_migrate_folio()

[kernel test robot]

Hi "Matthew,

I love your patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v5.19-rc1 next-20220607]
[cannot apply to jaegeuk-f2fs/dev-test trondmy-nfs/linux-next kdave/for-next xfs-linux/for-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/intel-lab-lkp/linux/commits/Matthew-Wilcox-Oracle/Convert-aops-migratepage-to-aops-migrate_folio/20220607-044509
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git f2906aa863381afb0015a9eb7fefad885d4e5a56
config: s390-randconfig-c005-20220606 (https://download.01.org/0day-ci/archive/20220607/202206071552.6lOdScLW-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project b92436efcb7813fc481b30f2593a4907568d917a)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install s390 cross compiling tool for clang build
        # apt-get install binutils-s390x-linux-gnu
        # https://github.com/intel-lab-lkp/linux/commit/96e64ba8b1be545885d89f44b1d8b968b22bdb4d
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Matthew-Wilcox-Oracle/Convert-aops-migratepage-to-aops-migrate_folio/20220607-044509
        git checkout 96e64ba8b1be545885d89f44b1d8b968b22bdb4d
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> mm/migrate.c:775: warning: expecting prototype for buffer_migrate_folio_noref(). Prototype was for buffer_migrate_folio_norefs() instead


vim +775 mm/migrate.c

89cb0888ca1483 Jan Kara                2018-12-28  758  
96e64ba8b1be54 Matthew Wilcox (Oracle  2022-06-06  759) /**
96e64ba8b1be54 Matthew Wilcox (Oracle  2022-06-06  760)  * buffer_migrate_folio_noref() - Migration function for folios with buffers.
96e64ba8b1be54 Matthew Wilcox (Oracle  2022-06-06  761)  * @mapping: The address space containing @src.
96e64ba8b1be54 Matthew Wilcox (Oracle  2022-06-06  762)  * @dst: The folio to migrate to.
96e64ba8b1be54 Matthew Wilcox (Oracle  2022-06-06  763)  * @src: The folio to migrate from.
96e64ba8b1be54 Matthew Wilcox (Oracle  2022-06-06  764)  * @mode: How to migrate the folio.
96e64ba8b1be54 Matthew Wilcox (Oracle  2022-06-06  765)  *
96e64ba8b1be54 Matthew Wilcox (Oracle  2022-06-06  766)  * Like buffer_migrate_folio() except that this variant is more careful
96e64ba8b1be54 Matthew Wilcox (Oracle  2022-06-06  767)  * and checks that there are also no buffer head references. This function
96e64ba8b1be54 Matthew Wilcox (Oracle  2022-06-06  768)  * is the right one for mappings where buffer heads are directly looked
96e64ba8b1be54 Matthew Wilcox (Oracle  2022-06-06  769)  * up and referenced (such as block device mappings).
96e64ba8b1be54 Matthew Wilcox (Oracle  2022-06-06  770)  *
96e64ba8b1be54 Matthew Wilcox (Oracle  2022-06-06  771)  * Return: 0 on success or a negative errno on failure.
89cb0888ca1483 Jan Kara                2018-12-28  772   */
96e64ba8b1be54 Matthew Wilcox (Oracle  2022-06-06  773) int buffer_migrate_folio_norefs(struct address_space *mapping,
96e64ba8b1be54 Matthew Wilcox (Oracle  2022-06-06  774) 		struct folio *dst, struct folio *src, enum migrate_mode mode)
89cb0888ca1483 Jan Kara                2018-12-28 @775  {
96e64ba8b1be54 Matthew Wilcox (Oracle  2022-06-06  776) 	return __buffer_migrate_folio(mapping, dst, src, mode, true);
89cb0888ca1483 Jan Kara                2018-12-28  777  }
9361401eb7619c David Howells           2006-09-30  778  #endif
1d8b85ccf1ed53 Christoph Lameter       2006-06-23  779  

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Re: [PATCH 04/20] mm/migrate: Convert buffer_migrate_page() to buffer_migrate_folio()

[Christoph Hellwig]

On Mon, Jun 06, 2022 at 09:40:34PM +0100, Matthew Wilcox (Oracle) wrote:
> Use a folio throughout __buffer_migrate_folio(), add kernel-doc for
> buffer_migrate_folio() and buffer_migrate_folio_norefs(), move their
> declarations to buffer.h and switch all filesystems that have wired
> them up.

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

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[PATCH 05/20] mm/migrate: Convert expected_page_refs() to folio_expected_refs()

[Matthew Wilcox (Oracle)]

Now that both callers have a folio, convert this function to
take a folio & rename it.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/migrate.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index 77b8c662c9ca..e0a593e5b5f9 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -337,13 +337,18 @@ void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd)
 }
 #endif
 
-static int expected_page_refs(struct address_space *mapping, struct page *page)
+static int folio_expected_refs(struct address_space *mapping,
+		struct folio *folio)
 {
-	int expected_count = 1;
+	int refs = 1;
+	if (!mapping)
+		return refs;
 
-	if (mapping)
-		expected_count += compound_nr(page) + page_has_private(page);
-	return expected_count;
+	refs += folio_nr_pages(folio);
+	if (folio_get_private(folio))
+		refs++;
+
+	return refs;;
 }
 
 /*
@@ -360,7 +365,7 @@ int folio_migrate_mapping(struct address_space *mapping,
 	XA_STATE(xas, &mapping->i_pages, folio_index(folio));
 	struct zone *oldzone, *newzone;
 	int dirty;
-	int expected_count = expected_page_refs(mapping, &folio->page) + extra_count;
+	int expected_count = folio_expected_refs(mapping, folio) + extra_count;
 	long nr = folio_nr_pages(folio);
 
 	if (!mapping) {
@@ -670,7 +675,7 @@ static int __buffer_migrate_folio(struct address_space *mapping,
 		return migrate_page(mapping, &dst->page, &src->page, mode);
 
 	/* Check whether page does not have extra refs before we do more work */
-	expected_count = expected_page_refs(mapping, &src->page);
+	expected_count = folio_expected_refs(mapping, src);
 	if (folio_ref_count(src) != expected_count)
 		return -EAGAIN;
 
-- 
2.35.1


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Re: [PATCH 05/20] mm/migrate: Convert expected_page_refs() to folio_expected_refs()

[Brian Foster]

On Mon, Jun 06, 2022 at 09:40:35PM +0100, Matthew Wilcox (Oracle) wrote:
> Now that both callers have a folio, convert this function to
> take a folio & rename it.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>  mm/migrate.c | 19 ++++++++++++-------
>  1 file changed, 12 insertions(+), 7 deletions(-)
> 
> diff --git a/mm/migrate.c b/mm/migrate.c
> index 77b8c662c9ca..e0a593e5b5f9 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -337,13 +337,18 @@ void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd)
>  }
>  #endif
>  
> -static int expected_page_refs(struct address_space *mapping, struct page *page)
> +static int folio_expected_refs(struct address_space *mapping,
> +		struct folio *folio)
>  {
> -	int expected_count = 1;
> +	int refs = 1;
> +	if (!mapping)
> +		return refs;
>  
> -	if (mapping)
> -		expected_count += compound_nr(page) + page_has_private(page);
> -	return expected_count;
> +	refs += folio_nr_pages(folio);
> +	if (folio_get_private(folio))
> +		refs++;

Why not folio_has_private() (as seems to be used for later
page_has_private() conversions) here?

> +
> +	return refs;;

Nit: extra ;

Brian

>  }
>  
>  /*
> @@ -360,7 +365,7 @@ int folio_migrate_mapping(struct address_space *mapping,
>  	XA_STATE(xas, &mapping->i_pages, folio_index(folio));
>  	struct zone *oldzone, *newzone;
>  	int dirty;
> -	int expected_count = expected_page_refs(mapping, &folio->page) + extra_count;
> +	int expected_count = folio_expected_refs(mapping, folio) + extra_count;
>  	long nr = folio_nr_pages(folio);
>  
>  	if (!mapping) {
> @@ -670,7 +675,7 @@ static int __buffer_migrate_folio(struct address_space *mapping,
>  		return migrate_page(mapping, &dst->page, &src->page, mode);
>  
>  	/* Check whether page does not have extra refs before we do more work */
> -	expected_count = expected_page_refs(mapping, &src->page);
> +	expected_count = folio_expected_refs(mapping, src);
>  	if (folio_ref_count(src) != expected_count)
>  		return -EAGAIN;
>  
> -- 
> 2.35.1
> 
> 


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Re: [PATCH 05/20] mm/migrate: Convert expected_page_refs() to folio_expected_refs()

[Matthew Wilcox]

On Tue, Jun 07, 2022 at 09:41:57AM -0400, Brian Foster wrote:
> On Mon, Jun 06, 2022 at 09:40:35PM +0100, Matthew Wilcox (Oracle) wrote:
> > -static int expected_page_refs(struct address_space *mapping, struct page *page)
> > +static int folio_expected_refs(struct address_space *mapping,
> > +		struct folio *folio)
> >  {
> > -	int expected_count = 1;
> > +	int refs = 1;
> > +	if (!mapping)
> > +		return refs;
> >  
> > -	if (mapping)
> > -		expected_count += compound_nr(page) + page_has_private(page);
> > -	return expected_count;
> > +	refs += folio_nr_pages(folio);
> > +	if (folio_get_private(folio))
> > +		refs++;
> 
> Why not folio_has_private() (as seems to be used for later
> page_has_private() conversions) here?

We have a horrid confusion that I'm trying to clean up stealthily
without anyone noticing.  I would have gotten away with it too if it
weren't for you pesky kids.

#define PAGE_FLAGS_PRIVATE                              \
        (1UL << PG_private | 1UL << PG_private_2)

static inline int page_has_private(struct page *page)
{
        return !!(page->flags & PAGE_FLAGS_PRIVATE);
}

So what this function is saying is that there is one extra refcount
expected on the struct page if PG_private _or_ PG_private_2 is set.

How are filesystems expected to manage their page's refcount with this
rule?  Increment the refcount when setting PG_private unless
PG_private_2 is already set?  Decrement the refcount when clearing
PG_private_2 unless PG_private is set?

This is garbage.  IMO, PG_private_2 should have no bearing on the page's
refcount.  Only btrfs and the netfs's use private_2 and neither of them
do anything to the refcount when setting/clearing it.  So that's what
I'm implementing here.

> > +
> > +	return refs;;
> 
> Nit: extra ;

Oh, that's where it went ;-)  I had a compile error due to a missing
semicolon at some point, and thought it was just a typo ...

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Re: [PATCH 05/20] mm/migrate: Convert expected_page_refs() to folio_expected_refs()

[Christoph Hellwig]

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

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[PATCH 06/20] btrfs: Convert btree_migratepage to migrate_folio

[Matthew Wilcox (Oracle)]

Use a folio throughout this function.  migrate_page() will be converted
later.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/btrfs/disk-io.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 12b11e645c14..9ceb73f683af 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -952,28 +952,28 @@ void btrfs_submit_metadata_bio(struct inode *inode, struct bio *bio, int mirror_
 }
 
 #ifdef CONFIG_MIGRATION
-static int btree_migratepage(struct address_space *mapping,
-			struct page *newpage, struct page *page,
-			enum migrate_mode mode)
+static int btree_migrate_folio(struct address_space *mapping,
+		struct folio *dst, struct folio *src, enum migrate_mode mode)
 {
 	/*
 	 * we can't safely write a btree page from here,
 	 * we haven't done the locking hook
 	 */
-	if (PageDirty(page))
+	if (folio_test_dirty(src))
 		return -EAGAIN;
 	/*
 	 * Buffers may be managed in a filesystem specific way.
 	 * We must have no buffers or drop them.
 	 */
-	if (page_has_private(page) &&
-	    !try_to_release_page(page, GFP_KERNEL))
+	if (folio_get_private(src) &&
+	    !filemap_release_folio(src, GFP_KERNEL))
 		return -EAGAIN;
-	return migrate_page(mapping, newpage, page, mode);
+	return migrate_page(mapping, &dst->page, &src->page, mode);
 }
+#else
+#define btree_migrate_folio NULL
 #endif
 
-
 static int btree_writepages(struct address_space *mapping,
 			    struct writeback_control *wbc)
 {
@@ -1073,10 +1073,8 @@ static const struct address_space_operations btree_aops = {
 	.writepages	= btree_writepages,
 	.release_folio	= btree_release_folio,
 	.invalidate_folio = btree_invalidate_folio,
-#ifdef CONFIG_MIGRATION
-	.migratepage	= btree_migratepage,
-#endif
-	.dirty_folio = btree_dirty_folio,
+	.migrate_folio	= btree_migrate_folio,
+	.dirty_folio	= btree_dirty_folio,
 };
 
 struct extent_buffer *btrfs_find_create_tree_block(
-- 
2.35.1


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Re: [PATCH 06/20] btrfs: Convert btree_migratepage to migrate_folio

[Christoph Hellwig]

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

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[PATCH 07/20] nfs: Convert to migrate_folio

[Matthew Wilcox (Oracle)]

Use a folio throughout this function.  migrate_page() will be converted
later.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/nfs/file.c     |  4 +---
 fs/nfs/internal.h |  6 ++++--
 fs/nfs/write.c    | 16 ++++++++--------
 3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 2d72b1b7ed74..549baed76351 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -533,9 +533,7 @@ const struct address_space_operations nfs_file_aops = {
 	.write_end = nfs_write_end,
 	.invalidate_folio = nfs_invalidate_folio,
 	.release_folio = nfs_release_folio,
-#ifdef CONFIG_MIGRATION
-	.migratepage = nfs_migrate_page,
-#endif
+	.migrate_folio = nfs_migrate_folio,
 	.launder_folio = nfs_launder_folio,
 	.is_dirty_writeback = nfs_check_dirty_writeback,
 	.error_remove_page = generic_error_remove_page,
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 8f8cd6e2d4db..437ebe544aaf 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -578,8 +578,10 @@ void nfs_clear_pnfs_ds_commit_verifiers(struct pnfs_ds_commit_info *cinfo)
 #endif
 
 #ifdef CONFIG_MIGRATION
-extern int nfs_migrate_page(struct address_space *,
-		struct page *, struct page *, enum migrate_mode);
+int nfs_migrate_folio(struct address_space *, struct folio *dst,
+		struct folio *src, enum migrate_mode);
+#else
+#define nfs_migrate_folio NULL
 #endif
 
 static inline int
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 1c706465d090..649b9e633459 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -2119,27 +2119,27 @@ int nfs_wb_page(struct inode *inode, struct page *page)
 }
 
 #ifdef CONFIG_MIGRATION
-int nfs_migrate_page(struct address_space *mapping, struct page *newpage,
-		struct page *page, enum migrate_mode mode)
+int nfs_migrate_folio(struct address_space *mapping, struct folio *dst,
+		struct folio *src, enum migrate_mode mode)
 {
 	/*
-	 * If PagePrivate is set, then the page is currently associated with
+	 * If the private flag is set, the folio is currently associated with
 	 * an in-progress read or write request. Don't try to migrate it.
 	 *
 	 * FIXME: we could do this in principle, but we'll need a way to ensure
 	 *        that we can safely release the inode reference while holding
-	 *        the page lock.
+	 *        the folio lock.
 	 */
-	if (PagePrivate(page))
+	if (folio_test_private(src))
 		return -EBUSY;
 
-	if (PageFsCache(page)) {
+	if (folio_test_fscache(src)) {
 		if (mode == MIGRATE_ASYNC)
 			return -EBUSY;
-		wait_on_page_fscache(page);
+		folio_wait_fscache(src);
 	}
 
-	return migrate_page(mapping, newpage, page, mode);
+	return migrate_page(mapping, &dst->page, &src->page, mode);
 }
 #endif
 
-- 
2.35.1


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Re: [PATCH 07/20] nfs: Convert to migrate_folio

[Anna Schumaker]

On Mon, Jun 6, 2022 at 7:37 PM Matthew Wilcox (Oracle)
<willy@infradead.org> wrote:
>
> Use a folio throughout this function.  migrate_page() will be converted
> later.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Looks fairly straightforward.

Acked-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

> ---
>  fs/nfs/file.c     |  4 +---
>  fs/nfs/internal.h |  6 ++++--
>  fs/nfs/write.c    | 16 ++++++++--------
>  3 files changed, 13 insertions(+), 13 deletions(-)
>
> diff --git a/fs/nfs/file.c b/fs/nfs/file.c
> index 2d72b1b7ed74..549baed76351 100644
> --- a/fs/nfs/file.c
> +++ b/fs/nfs/file.c
> @@ -533,9 +533,7 @@ const struct address_space_operations nfs_file_aops = {
>         .write_end = nfs_write_end,
>         .invalidate_folio = nfs_invalidate_folio,
>         .release_folio = nfs_release_folio,
> -#ifdef CONFIG_MIGRATION
> -       .migratepage = nfs_migrate_page,
> -#endif
> +       .migrate_folio = nfs_migrate_folio,
>         .launder_folio = nfs_launder_folio,
>         .is_dirty_writeback = nfs_check_dirty_writeback,
>         .error_remove_page = generic_error_remove_page,
> diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
> index 8f8cd6e2d4db..437ebe544aaf 100644
> --- a/fs/nfs/internal.h
> +++ b/fs/nfs/internal.h
> @@ -578,8 +578,10 @@ void nfs_clear_pnfs_ds_commit_verifiers(struct pnfs_ds_commit_info *cinfo)
>  #endif
>
>  #ifdef CONFIG_MIGRATION
> -extern int nfs_migrate_page(struct address_space *,
> -               struct page *, struct page *, enum migrate_mode);
> +int nfs_migrate_folio(struct address_space *, struct folio *dst,
> +               struct folio *src, enum migrate_mode);
> +#else
> +#define nfs_migrate_folio NULL
>  #endif
>
>  static inline int
> diff --git a/fs/nfs/write.c b/fs/nfs/write.c
> index 1c706465d090..649b9e633459 100644
> --- a/fs/nfs/write.c
> +++ b/fs/nfs/write.c
> @@ -2119,27 +2119,27 @@ int nfs_wb_page(struct inode *inode, struct page *page)
>  }
>
>  #ifdef CONFIG_MIGRATION
> -int nfs_migrate_page(struct address_space *mapping, struct page *newpage,
> -               struct page *page, enum migrate_mode mode)
> +int nfs_migrate_folio(struct address_space *mapping, struct folio *dst,
> +               struct folio *src, enum migrate_mode mode)
>  {
>         /*
> -        * If PagePrivate is set, then the page is currently associated with
> +        * If the private flag is set, the folio is currently associated with
>          * an in-progress read or write request. Don't try to migrate it.
>          *
>          * FIXME: we could do this in principle, but we'll need a way to ensure
>          *        that we can safely release the inode reference while holding
> -        *        the page lock.
> +        *        the folio lock.
>          */
> -       if (PagePrivate(page))
> +       if (folio_test_private(src))
>                 return -EBUSY;
>
> -       if (PageFsCache(page)) {
> +       if (folio_test_fscache(src)) {
>                 if (mode == MIGRATE_ASYNC)
>                         return -EBUSY;
> -               wait_on_page_fscache(page);
> +               folio_wait_fscache(src);
>         }
>
> -       return migrate_page(mapping, newpage, page, mode);
> +       return migrate_page(mapping, &dst->page, &src->page, mode);
>  }
>  #endif
>
> --
> 2.35.1
>

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Re: [PATCH 07/20] nfs: Convert to migrate_folio

[Christoph Hellwig]

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

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[PATCH 08/20] mm/migrate: Convert migrate_page() to migrate_folio()

[Matthew Wilcox (Oracle)]

Convert all callers to pass a folio.  Most have the folio
already available.  Switch all users from aops->migratepage to
aops->migrate_folio.  Also turn the documentation into kerneldoc.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 drivers/gpu/drm/i915/gem/i915_gem_userptr.c |  4 +--
 fs/btrfs/disk-io.c                          |  2 +-
 fs/nfs/write.c                              |  2 +-
 include/linux/migrate.h                     |  5 ++-
 mm/migrate.c                                | 37 +++++++++++----------
 mm/migrate_device.c                         |  3 +-
 mm/shmem.c                                  |  2 +-
 mm/swap_state.c                             |  2 +-
 8 files changed, 30 insertions(+), 27 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
index 094f06b4ce33..8423df021b71 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
@@ -216,8 +216,8 @@ i915_gem_userptr_put_pages(struct drm_i915_gem_object *obj,
 			 * However...!
 			 *
 			 * The mmu-notifier can be invalidated for a
-			 * migrate_page, that is alreadying holding the lock
-			 * on the page. Such a try_to_unmap() will result
+			 * migrate_folio, that is alreadying holding the lock
+			 * on the folio. Such a try_to_unmap() will result
 			 * in us calling put_pages() and so recursively try
 			 * to lock the page. We avoid that deadlock with
 			 * a trylock_page() and in exchange we risk missing
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 9ceb73f683af..8e5f1fa1e972 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -968,7 +968,7 @@ static int btree_migrate_folio(struct address_space *mapping,
 	if (folio_get_private(src) &&
 	    !filemap_release_folio(src, GFP_KERNEL))
 		return -EAGAIN;
-	return migrate_page(mapping, &dst->page, &src->page, mode);
+	return migrate_folio(mapping, dst, src, mode);
 }
 #else
 #define btree_migrate_folio NULL
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 649b9e633459..69569696dde0 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -2139,7 +2139,7 @@ int nfs_migrate_folio(struct address_space *mapping, struct folio *dst,
 		folio_wait_fscache(src);
 	}
 
-	return migrate_page(mapping, &dst->page, &src->page, mode);
+	return migrate_folio(mapping, dst, src, mode);
 }
 #endif
 
diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 069a89e847f3..4ef22806cd8e 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -25,9 +25,8 @@ extern const char *migrate_reason_names[MR_TYPES];
 #ifdef CONFIG_MIGRATION
 
 extern void putback_movable_pages(struct list_head *l);
-extern int migrate_page(struct address_space *mapping,
-			struct page *newpage, struct page *page,
-			enum migrate_mode mode);
+int migrate_folio(struct address_space *mapping, struct folio *dst,
+		struct folio *src, enum migrate_mode mode);
 extern int migrate_pages(struct list_head *l, new_page_t new, free_page_t free,
 		unsigned long private, enum migrate_mode mode, int reason,
 		unsigned int *ret_succeeded);
diff --git a/mm/migrate.c b/mm/migrate.c
index e0a593e5b5f9..6232c291fdb9 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -594,34 +594,37 @@ EXPORT_SYMBOL(folio_migrate_copy);
  *                    Migration functions
  ***********************************************************/
 
-/*
- * Common logic to directly migrate a single LRU page suitable for
- * pages that do not use PagePrivate/PagePrivate2.
+/**
+ * migrate_folio() - Simple folio migration.
+ * @mapping: The address_space containing the folio.
+ * @dst: The folio to migrate the data to.
+ * @src: The folio containing the current data.
+ * @mode: How to migrate the page.
  *
- * Pages are locked upon entry and exit.
+ * Common logic to directly migrate a single LRU folio suitable for
+ * folios that do not use PagePrivate/PagePrivate2.
+ *
+ * Folios are locked upon entry and exit.
  */
-int migrate_page(struct address_space *mapping,
-		struct page *newpage, struct page *page,
-		enum migrate_mode mode)
+int migrate_folio(struct address_space *mapping, struct folio *dst,
+		struct folio *src, enum migrate_mode mode)
 {
-	struct folio *newfolio = page_folio(newpage);
-	struct folio *folio = page_folio(page);
 	int rc;
 
-	BUG_ON(folio_test_writeback(folio));	/* Writeback must be complete */
+	BUG_ON(folio_test_writeback(src));	/* Writeback must be complete */
 
-	rc = folio_migrate_mapping(mapping, newfolio, folio, 0);
+	rc = folio_migrate_mapping(mapping, dst, src, 0);
 
 	if (rc != MIGRATEPAGE_SUCCESS)
 		return rc;
 
 	if (mode != MIGRATE_SYNC_NO_COPY)
-		folio_migrate_copy(newfolio, folio);
+		folio_migrate_copy(dst, src);
 	else
-		folio_migrate_flags(newfolio, folio);
+		folio_migrate_flags(dst, src);
 	return MIGRATEPAGE_SUCCESS;
 }
-EXPORT_SYMBOL(migrate_page);
+EXPORT_SYMBOL(migrate_folio);
 
 #ifdef CONFIG_BLOCK
 /* Returns true if all buffers are successfully locked */
@@ -672,7 +675,7 @@ static int __buffer_migrate_folio(struct address_space *mapping,
 
 	head = folio_buffers(src);
 	if (!head)
-		return migrate_page(mapping, &dst->page, &src->page, mode);
+		return migrate_folio(mapping, dst, src, mode);
 
 	/* Check whether page does not have extra refs before we do more work */
 	expected_count = folio_expected_refs(mapping, src);
@@ -849,7 +852,7 @@ static int fallback_migrate_folio(struct address_space *mapping,
 	    !filemap_release_folio(src, GFP_KERNEL))
 		return mode == MIGRATE_SYNC ? -EAGAIN : -EBUSY;
 
-	return migrate_page(mapping, &dst->page, &src->page, mode);
+	return migrate_folio(mapping, dst, src, mode);
 }
 
 /*
@@ -877,7 +880,7 @@ static int move_to_new_folio(struct folio *dst, struct folio *src,
 
 	if (likely(is_lru)) {
 		if (!mapping)
-			rc = migrate_page(mapping, &dst->page, &src->page, mode);
+			rc = migrate_folio(mapping, dst, src, mode);
 		else if (mapping->a_ops->migrate_folio)
 			/*
 			 * Most folios have a mapping and most filesystems
diff --git a/mm/migrate_device.c b/mm/migrate_device.c
index 5052093d0262..5dd97c39ca6a 100644
--- a/mm/migrate_device.c
+++ b/mm/migrate_device.c
@@ -718,7 +718,8 @@ void migrate_vma_pages(struct migrate_vma *migrate)
 			continue;
 		}
 
-		r = migrate_page(mapping, newpage, page, MIGRATE_SYNC_NO_COPY);
+		r = migrate_folio(mapping, page_folio(newpage),
+				page_folio(page), MIGRATE_SYNC_NO_COPY);
 		if (r != MIGRATEPAGE_SUCCESS)
 			migrate->src[i] &= ~MIGRATE_PFN_MIGRATE;
 	}
diff --git a/mm/shmem.c b/mm/shmem.c
index 313ae7df59d8..e37ff6a1a6d0 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -3801,7 +3801,7 @@ const struct address_space_operations shmem_aops = {
 	.write_end	= shmem_write_end,
 #endif
 #ifdef CONFIG_MIGRATION
-	.migratepage	= migrate_page,
+	.migrate_folio	= migrate_folio,
 #endif
 	.error_remove_page = shmem_error_remove_page,
 };
diff --git a/mm/swap_state.c b/mm/swap_state.c
index f5b6f5638908..0a2021fc55ad 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -33,7 +33,7 @@ static const struct address_space_operations swap_aops = {
 	.writepage	= swap_writepage,
 	.dirty_folio	= noop_dirty_folio,
 #ifdef CONFIG_MIGRATION
-	.migratepage	= migrate_page,
+	.migrate_folio	= migrate_folio,
 #endif
 };
 
-- 
2.35.1


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Re: [PATCH 08/20] mm/migrate: Convert migrate_page() to migrate_folio()

[Christoph Hellwig]

On Mon, Jun 06, 2022 at 09:40:38PM +0100, Matthew Wilcox (Oracle) wrote:
> Convert all callers to pass a folio.  Most have the folio
> already available.  Switch all users from aops->migratepage to
> aops->migrate_folio.  Also turn the documentation into kerneldoc.

Reviewed-by: Christoph Hellwig <hch@lst.de>

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[PATCH 09/20] mm/migrate: Add filemap_migrate_folio()

[Matthew Wilcox (Oracle)]

There is nothing iomap-specific about iomap_migratepage(), and it fits
a pattern used by several other filesystems, so move it to mm/migrate.c,
convert it to be filemap_migrate_folio() and convert the iomap filesystems
to use it.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/gfs2/aops.c          |  2 +-
 fs/iomap/buffered-io.c  | 25 -------------------------
 fs/xfs/xfs_aops.c       |  2 +-
 fs/zonefs/super.c       |  2 +-
 include/linux/iomap.h   |  6 ------
 include/linux/pagemap.h |  6 ++++++
 mm/migrate.c            | 20 ++++++++++++++++++++
 7 files changed, 29 insertions(+), 34 deletions(-)

diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
index 106e90a36583..57ff883d432c 100644
--- a/fs/gfs2/aops.c
+++ b/fs/gfs2/aops.c
@@ -774,7 +774,7 @@ static const struct address_space_operations gfs2_aops = {
 	.invalidate_folio = iomap_invalidate_folio,
 	.bmap = gfs2_bmap,
 	.direct_IO = noop_direct_IO,
-	.migratepage = iomap_migrate_page,
+	.migrate_folio = filemap_migrate_folio,
 	.is_partially_uptodate = iomap_is_partially_uptodate,
 	.error_remove_page = generic_error_remove_page,
 };
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 66278a14bfa7..5a91aa1db945 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -489,31 +489,6 @@ void iomap_invalidate_folio(struct folio *folio, size_t offset, size_t len)
 }
 EXPORT_SYMBOL_GPL(iomap_invalidate_folio);
 
-#ifdef CONFIG_MIGRATION
-int
-iomap_migrate_page(struct address_space *mapping, struct page *newpage,
-		struct page *page, enum migrate_mode mode)
-{
-	struct folio *folio = page_folio(page);
-	struct folio *newfolio = page_folio(newpage);
-	int ret;
-
-	ret = folio_migrate_mapping(mapping, newfolio, folio, 0);
-	if (ret != MIGRATEPAGE_SUCCESS)
-		return ret;
-
-	if (folio_test_private(folio))
-		folio_attach_private(newfolio, folio_detach_private(folio));
-
-	if (mode != MIGRATE_SYNC_NO_COPY)
-		folio_migrate_copy(newfolio, folio);
-	else
-		folio_migrate_flags(newfolio, folio);
-	return MIGRATEPAGE_SUCCESS;
-}
-EXPORT_SYMBOL_GPL(iomap_migrate_page);
-#endif /* CONFIG_MIGRATION */
-
 static void
 iomap_write_failed(struct inode *inode, loff_t pos, unsigned len)
 {
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 8ec38b25187b..5d1a995b15f8 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -570,7 +570,7 @@ const struct address_space_operations xfs_address_space_operations = {
 	.invalidate_folio	= iomap_invalidate_folio,
 	.bmap			= xfs_vm_bmap,
 	.direct_IO		= noop_direct_IO,
-	.migratepage		= iomap_migrate_page,
+	.migrate_folio		= filemap_migrate_folio,
 	.is_partially_uptodate  = iomap_is_partially_uptodate,
 	.error_remove_page	= generic_error_remove_page,
 	.swap_activate		= xfs_iomap_swapfile_activate,
diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
index bcb21aea990a..d4c3f28f34ee 100644
--- a/fs/zonefs/super.c
+++ b/fs/zonefs/super.c
@@ -237,7 +237,7 @@ static const struct address_space_operations zonefs_file_aops = {
 	.dirty_folio		= filemap_dirty_folio,
 	.release_folio		= iomap_release_folio,
 	.invalidate_folio	= iomap_invalidate_folio,
-	.migratepage		= iomap_migrate_page,
+	.migrate_folio		= filemap_migrate_folio,
 	.is_partially_uptodate	= iomap_is_partially_uptodate,
 	.error_remove_page	= generic_error_remove_page,
 	.direct_IO		= noop_direct_IO,
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index e552097c67e0..758a1125e72f 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -231,12 +231,6 @@ void iomap_readahead(struct readahead_control *, const struct iomap_ops *ops);
 bool iomap_is_partially_uptodate(struct folio *, size_t from, size_t count);
 bool iomap_release_folio(struct folio *folio, gfp_t gfp_flags);
 void iomap_invalidate_folio(struct folio *folio, size_t offset, size_t len);
-#ifdef CONFIG_MIGRATION
-int iomap_migrate_page(struct address_space *mapping, struct page *newpage,
-		struct page *page, enum migrate_mode mode);
-#else
-#define iomap_migrate_page NULL
-#endif
 int iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len,
 		const struct iomap_ops *ops);
 int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 1caccb9f99aa..2a67c0ad7348 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -1078,6 +1078,12 @@ static inline int __must_check write_one_page(struct page *page)
 int __set_page_dirty_nobuffers(struct page *page);
 bool noop_dirty_folio(struct address_space *mapping, struct folio *folio);
 
+#ifdef CONFIG_MIGRATION
+int filemap_migrate_folio(struct address_space *mapping, struct folio *dst,
+		struct folio *src, enum migrate_mode mode);
+#else
+#define filemap_migrate_folio NULL
+#endif
 void page_endio(struct page *page, bool is_write, int err);
 
 void folio_end_private_2(struct folio *folio);
diff --git a/mm/migrate.c b/mm/migrate.c
index 6232c291fdb9..148dd0463dec 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -785,6 +785,26 @@ int buffer_migrate_folio_norefs(struct address_space *mapping,
 }
 #endif
 
+int filemap_migrate_folio(struct address_space *mapping,
+		struct folio *dst, struct folio *src, enum migrate_mode mode)
+{
+	int ret;
+
+	ret = folio_migrate_mapping(mapping, dst, src, 0);
+	if (ret != MIGRATEPAGE_SUCCESS)
+		return ret;
+
+	if (folio_get_private(src))
+		folio_attach_private(dst, folio_detach_private(src));
+
+	if (mode != MIGRATE_SYNC_NO_COPY)
+		folio_migrate_copy(dst, src);
+	else
+		folio_migrate_flags(dst, src);
+	return MIGRATEPAGE_SUCCESS;
+}
+EXPORT_SYMBOL_GPL(filemap_migrate_folio);
+
 /*
  * Writeback a folio to clean the dirty state
  */
-- 
2.35.1


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Re: [PATCH 09/20] mm/migrate: Add filemap_migrate_folio()

[Christoph Hellwig]

On Mon, Jun 06, 2022 at 09:40:39PM +0100, Matthew Wilcox (Oracle) wrote:
> There is nothing iomap-specific about iomap_migratepage(), and it fits
> a pattern used by several other filesystems, so move it to mm/migrate.c,
> convert it to be filemap_migrate_folio() and convert the iomap filesystems
> to use it.

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

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[PATCH 10/20] btrfs: Convert btrfs_migratepage to migrate_folio

[Matthew Wilcox (Oracle)]

Use filemap_migrate_folio() to do the bulk of the work, and then copy
the ordered flag across if needed.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/btrfs/inode.c | 26 +++++++++-----------------
 1 file changed, 9 insertions(+), 17 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 81737eff92f3..5f41d869c648 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -8255,30 +8255,24 @@ static bool btrfs_release_folio(struct folio *folio, gfp_t gfp_flags)
 }
 
 #ifdef CONFIG_MIGRATION
-static int btrfs_migratepage(struct address_space *mapping,
-			     struct page *newpage, struct page *page,
+static int btrfs_migrate_folio(struct address_space *mapping,
+			     struct folio *dst, struct folio *src,
 			     enum migrate_mode mode)
 {
-	int ret;
+	int ret = filemap_migrate_folio(mapping, dst, src, mode);
 
-	ret = migrate_page_move_mapping(mapping, newpage, page, 0);
 	if (ret != MIGRATEPAGE_SUCCESS)
 		return ret;
 
-	if (page_has_private(page))
-		attach_page_private(newpage, detach_page_private(page));
-
-	if (PageOrdered(page)) {
-		ClearPageOrdered(page);
-		SetPageOrdered(newpage);
+	if (folio_test_ordered(src)) {
+		folio_clear_ordered(src);
+		folio_set_ordered(dst);
 	}
 
-	if (mode != MIGRATE_SYNC_NO_COPY)
-		migrate_page_copy(newpage, page);
-	else
-		migrate_page_states(newpage, page);
 	return MIGRATEPAGE_SUCCESS;
 }
+#else
+#define btrfs_migrate_folio NULL
 #endif
 
 static void btrfs_invalidate_folio(struct folio *folio, size_t offset,
@@ -11422,9 +11416,7 @@ static const struct address_space_operations btrfs_aops = {
 	.direct_IO	= noop_direct_IO,
 	.invalidate_folio = btrfs_invalidate_folio,
 	.release_folio	= btrfs_release_folio,
-#ifdef CONFIG_MIGRATION
-	.migratepage	= btrfs_migratepage,
-#endif
+	.migrate_folio	= btrfs_migrate_folio,
 	.dirty_folio	= filemap_dirty_folio,
 	.error_remove_page = generic_error_remove_page,
 	.swap_activate	= btrfs_swap_activate,
-- 
2.35.1


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Re: [PATCH 10/20] btrfs: Convert btrfs_migratepage to migrate_folio

[Christoph Hellwig]

On Mon, Jun 06, 2022 at 09:40:40PM +0100, Matthew Wilcox (Oracle) wrote:
> Use filemap_migrate_folio() to do the bulk of the work, and then copy
> the ordered flag across if needed.

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

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[PATCH 11/20] ubifs: Convert to filemap_migrate_folio()

[Matthew Wilcox (Oracle)]

filemap_migrate_folio() is a little more general than ubifs really needs,
but it's better to share the code.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/ubifs/file.c | 29 ++---------------------------
 1 file changed, 2 insertions(+), 27 deletions(-)

diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 04ced154960f..f2353dd676ef 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1461,29 +1461,6 @@ static bool ubifs_dirty_folio(struct address_space *mapping,
 	return ret;
 }
 
-#ifdef CONFIG_MIGRATION
-static int ubifs_migrate_page(struct address_space *mapping,
-		struct page *newpage, struct page *page, enum migrate_mode mode)
-{
-	int rc;
-
-	rc = migrate_page_move_mapping(mapping, newpage, page, 0);
-	if (rc != MIGRATEPAGE_SUCCESS)
-		return rc;
-
-	if (PagePrivate(page)) {
-		detach_page_private(page);
-		attach_page_private(newpage, (void *)1);
-	}
-
-	if (mode != MIGRATE_SYNC_NO_COPY)
-		migrate_page_copy(newpage, page);
-	else
-		migrate_page_states(newpage, page);
-	return MIGRATEPAGE_SUCCESS;
-}
-#endif
-
 static bool ubifs_release_folio(struct folio *folio, gfp_t unused_gfp_flags)
 {
 	struct inode *inode = folio->mapping->host;
@@ -1649,10 +1626,8 @@ const struct address_space_operations ubifs_file_address_operations = {
 	.write_end      = ubifs_write_end,
 	.invalidate_folio = ubifs_invalidate_folio,
 	.dirty_folio	= ubifs_dirty_folio,
-#ifdef CONFIG_MIGRATION
-	.migratepage	= ubifs_migrate_page,
-#endif
-	.release_folio    = ubifs_release_folio,
+	.migrate_folio	= filemap_migrate_folio,
+	.release_folio	= ubifs_release_folio,
 };
 
 const struct inode_operations ubifs_file_inode_operations = {
-- 
2.35.1


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[PATCH 12/20] f2fs: Convert to filemap_migrate_folio()

[Matthew Wilcox (Oracle)]

filemap_migrate_folio() fits f2fs's needs perfectly.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/f2fs/checkpoint.c |  4 +---
 fs/f2fs/data.c       | 40 +---------------------------------------
 fs/f2fs/f2fs.h       |  4 ----
 fs/f2fs/node.c       |  4 +---
 4 files changed, 3 insertions(+), 49 deletions(-)

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 6d8b2bf14de0..8259e0fa97e1 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -463,9 +463,7 @@ const struct address_space_operations f2fs_meta_aops = {
 	.dirty_folio	= f2fs_dirty_meta_folio,
 	.invalidate_folio = f2fs_invalidate_folio,
 	.release_folio	= f2fs_release_folio,
-#ifdef CONFIG_MIGRATION
-	.migratepage    = f2fs_migrate_page,
-#endif
+	.migrate_folio	= filemap_migrate_folio,
 };
 
 static void __add_ino_entry(struct f2fs_sb_info *sbi, nid_t ino,
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 7fcbcf979737..318a3f91ad74 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -3751,42 +3751,6 @@ static sector_t f2fs_bmap(struct address_space *mapping, sector_t block)
 	return blknr;
 }
 
-#ifdef CONFIG_MIGRATION
-#include <linux/migrate.h>
-
-int f2fs_migrate_page(struct address_space *mapping,
-		struct page *newpage, struct page *page, enum migrate_mode mode)
-{
-	int rc, extra_count = 0;
-
-	BUG_ON(PageWriteback(page));
-
-	rc = migrate_page_move_mapping(mapping, newpage,
-				page, extra_count);
-	if (rc != MIGRATEPAGE_SUCCESS)
-		return rc;
-
-	/* guarantee to start from no stale private field */
-	set_page_private(newpage, 0);
-	if (PagePrivate(page)) {
-		set_page_private(newpage, page_private(page));
-		SetPagePrivate(newpage);
-		get_page(newpage);
-
-		set_page_private(page, 0);
-		ClearPagePrivate(page);
-		put_page(page);
-	}
-
-	if (mode != MIGRATE_SYNC_NO_COPY)
-		migrate_page_copy(newpage, page);
-	else
-		migrate_page_states(newpage, page);
-
-	return MIGRATEPAGE_SUCCESS;
-}
-#endif
-
 #ifdef CONFIG_SWAP
 static int f2fs_migrate_blocks(struct inode *inode, block_t start_blk,
 							unsigned int blkcnt)
@@ -4018,15 +3982,13 @@ const struct address_space_operations f2fs_dblock_aops = {
 	.write_begin	= f2fs_write_begin,
 	.write_end	= f2fs_write_end,
 	.dirty_folio	= f2fs_dirty_data_folio,
+	.migrate_folio	= filemap_migrate_folio,
 	.invalidate_folio = f2fs_invalidate_folio,
 	.release_folio	= f2fs_release_folio,
 	.direct_IO	= noop_direct_IO,
 	.bmap		= f2fs_bmap,
 	.swap_activate  = f2fs_swap_activate,
 	.swap_deactivate = f2fs_swap_deactivate,
-#ifdef CONFIG_MIGRATION
-	.migratepage    = f2fs_migrate_page,
-#endif
 };
 
 void f2fs_clear_page_cache_dirty_tag(struct page *page)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index d9bbecd008d2..f258a1b6faed 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3764,10 +3764,6 @@ int f2fs_write_single_data_page(struct page *page, int *submitted,
 void f2fs_write_failed(struct inode *inode, loff_t to);
 void f2fs_invalidate_folio(struct folio *folio, size_t offset, size_t length);
 bool f2fs_release_folio(struct folio *folio, gfp_t wait);
-#ifdef CONFIG_MIGRATION
-int f2fs_migrate_page(struct address_space *mapping, struct page *newpage,
-			struct page *page, enum migrate_mode mode);
-#endif
 bool f2fs_overwrite_io(struct inode *inode, loff_t pos, size_t len);
 void f2fs_clear_page_cache_dirty_tag(struct page *page);
 int f2fs_init_post_read_processing(void);
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 836c79a20afc..ed1cbfb0345f 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -2163,9 +2163,7 @@ const struct address_space_operations f2fs_node_aops = {
 	.dirty_folio	= f2fs_dirty_node_folio,
 	.invalidate_folio = f2fs_invalidate_folio,
 	.release_folio	= f2fs_release_folio,
-#ifdef CONFIG_MIGRATION
-	.migratepage	= f2fs_migrate_page,
-#endif
+	.migrate_folio	= filemap_migrate_folio,
 };
 
 static struct free_nid *__lookup_free_nid_list(struct f2fs_nm_info *nm_i,
-- 
2.35.1


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[PATCH 13/20] aio: Convert to migrate_folio

[Matthew Wilcox (Oracle)]

Use a folio throughout this function.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/aio.c | 36 ++++++++++++++++++------------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index 3c249b938632..a1911e86859c 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -400,8 +400,8 @@ static const struct file_operations aio_ring_fops = {
 };
 
 #if IS_ENABLED(CONFIG_MIGRATION)
-static int aio_migratepage(struct address_space *mapping, struct page *new,
-			struct page *old, enum migrate_mode mode)
+static int aio_migrate_folio(struct address_space *mapping, struct folio *dst,
+			struct folio *src, enum migrate_mode mode)
 {
 	struct kioctx *ctx;
 	unsigned long flags;
@@ -435,10 +435,10 @@ static int aio_migratepage(struct address_space *mapping, struct page *new,
 		goto out;
 	}
 
-	idx = old->index;
+	idx = src->index;
 	if (idx < (pgoff_t)ctx->nr_pages) {
-		/* Make sure the old page hasn't already been changed */
-		if (ctx->ring_pages[idx] != old)
+		/* Make sure the old folio hasn't already been changed */
+		if (ctx->ring_pages[idx] != &src->page)
 			rc = -EAGAIN;
 	} else
 		rc = -EINVAL;
@@ -447,27 +447,27 @@ static int aio_migratepage(struct address_space *mapping, struct page *new,
 		goto out_unlock;
 
 	/* Writeback must be complete */
-	BUG_ON(PageWriteback(old));
-	get_page(new);
+	BUG_ON(folio_test_writeback(src));
+	folio_get(dst);
 
-	rc = migrate_page_move_mapping(mapping, new, old, 1);
+	rc = folio_migrate_mapping(mapping, dst, src, 1);
 	if (rc != MIGRATEPAGE_SUCCESS) {
-		put_page(new);
+		folio_put(dst);
 		goto out_unlock;
 	}
 
 	/* Take completion_lock to prevent other writes to the ring buffer
-	 * while the old page is copied to the new.  This prevents new
+	 * while the old folio is copied to the new.  This prevents new
 	 * events from being lost.
 	 */
 	spin_lock_irqsave(&ctx->completion_lock, flags);
-	migrate_page_copy(new, old);
-	BUG_ON(ctx->ring_pages[idx] != old);
-	ctx->ring_pages[idx] = new;
+	folio_migrate_copy(dst, src);
+	BUG_ON(ctx->ring_pages[idx] != &src->page);
+	ctx->ring_pages[idx] = &dst->page;
 	spin_unlock_irqrestore(&ctx->completion_lock, flags);
 
-	/* The old page is no longer accessible. */
-	put_page(old);
+	/* The old folio is no longer accessible. */
+	folio_put(src);
 
 out_unlock:
 	mutex_unlock(&ctx->ring_lock);
@@ -475,13 +475,13 @@ static int aio_migratepage(struct address_space *mapping, struct page *new,
 	spin_unlock(&mapping->private_lock);
 	return rc;
 }
+#else
+#define aio_migrate_folio NULL
 #endif
 
 static const struct address_space_operations aio_ctx_aops = {
 	.dirty_folio	= noop_dirty_folio,
-#if IS_ENABLED(CONFIG_MIGRATION)
-	.migratepage	= aio_migratepage,
-#endif
+	.migrate_folio	= aio_migrate_folio,
 };
 
 static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)
-- 
2.35.1


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Re: [PATCH 13/20] aio: Convert to migrate_folio

[Christoph Hellwig]

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

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[PATCH 14/20] hugetlb: Convert to migrate_folio

[Matthew Wilcox (Oracle)]

This involves converting migrate_huge_page_move_mapping().  We also need a
folio variant of hugetlb_set_page_subpool(), but that's for a later patch.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/hugetlbfs/inode.c    | 19 ++++++++++---------
 include/linux/migrate.h |  6 +++---
 mm/migrate.c            | 18 +++++++++---------
 3 files changed, 22 insertions(+), 21 deletions(-)

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 14d33f725e05..583ca3f52c04 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -954,25 +954,26 @@ static int hugetlbfs_symlink(struct user_namespace *mnt_userns,
 	return error;
 }
 
-static int hugetlbfs_migrate_page(struct address_space *mapping,
-				struct page *newpage, struct page *page,
+static int hugetlbfs_migrate_folio(struct address_space *mapping,
+				struct folio *dst, struct folio *src,
 				enum migrate_mode mode)
 {
 	int rc;
 
-	rc = migrate_huge_page_move_mapping(mapping, newpage, page);
+	rc = migrate_huge_page_move_mapping(mapping, dst, src);
 	if (rc != MIGRATEPAGE_SUCCESS)
 		return rc;
 
-	if (hugetlb_page_subpool(page)) {
-		hugetlb_set_page_subpool(newpage, hugetlb_page_subpool(page));
-		hugetlb_set_page_subpool(page, NULL);
+	if (hugetlb_page_subpool(&src->page)) {
+		hugetlb_set_page_subpool(&dst->page,
+					hugetlb_page_subpool(&src->page));
+		hugetlb_set_page_subpool(&src->page, NULL);
 	}
 
 	if (mode != MIGRATE_SYNC_NO_COPY)
-		migrate_page_copy(newpage, page);
+		folio_migrate_copy(dst, src);
 	else
-		migrate_page_states(newpage, page);
+		folio_migrate_flags(dst, src);
 
 	return MIGRATEPAGE_SUCCESS;
 }
@@ -1142,7 +1143,7 @@ static const struct address_space_operations hugetlbfs_aops = {
 	.write_begin	= hugetlbfs_write_begin,
 	.write_end	= hugetlbfs_write_end,
 	.dirty_folio	= noop_dirty_folio,
-	.migratepage    = hugetlbfs_migrate_page,
+	.migrate_folio  = hugetlbfs_migrate_folio,
 	.error_remove_page	= hugetlbfs_error_remove_page,
 };
 
diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 4ef22806cd8e..088749471485 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -35,8 +35,8 @@ extern int isolate_movable_page(struct page *page, isolate_mode_t mode);
 
 extern void migrate_page_states(struct page *newpage, struct page *page);
 extern void migrate_page_copy(struct page *newpage, struct page *page);
-extern int migrate_huge_page_move_mapping(struct address_space *mapping,
-				  struct page *newpage, struct page *page);
+int migrate_huge_page_move_mapping(struct address_space *mapping,
+		struct folio *dst, struct folio *src);
 extern int migrate_page_move_mapping(struct address_space *mapping,
 		struct page *newpage, struct page *page, int extra_count);
 void migration_entry_wait_on_locked(swp_entry_t entry, pte_t *ptep,
@@ -67,7 +67,7 @@ static inline void migrate_page_copy(struct page *newpage,
 				     struct page *page) {}
 
 static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
-				  struct page *newpage, struct page *page)
+				  struct folio *dst, struct folio *src)
 {
 	return -ENOSYS;
 }
diff --git a/mm/migrate.c b/mm/migrate.c
index 148dd0463dec..a8edd226c72d 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -475,26 +475,26 @@ EXPORT_SYMBOL(folio_migrate_mapping);
  * of folio_migrate_mapping().
  */
 int migrate_huge_page_move_mapping(struct address_space *mapping,
-				   struct page *newpage, struct page *page)
+				   struct folio *dst, struct folio *src)
 {
-	XA_STATE(xas, &mapping->i_pages, page_index(page));
+	XA_STATE(xas, &mapping->i_pages, folio_index(src));
 	int expected_count;
 
 	xas_lock_irq(&xas);
-	expected_count = 2 + page_has_private(page);
-	if (!page_ref_freeze(page, expected_count)) {
+	expected_count = 2 + folio_has_private(src);
+	if (!folio_ref_freeze(src, expected_count)) {
 		xas_unlock_irq(&xas);
 		return -EAGAIN;
 	}
 
-	newpage->index = page->index;
-	newpage->mapping = page->mapping;
+	dst->index = src->index;
+	dst->mapping = src->mapping;
 
-	get_page(newpage);
+	folio_get(dst);
 
-	xas_store(&xas, newpage);
+	xas_store(&xas, dst);
 
-	page_ref_unfreeze(page, expected_count - 1);
+	folio_ref_unfreeze(src, expected_count - 1);
 
 	xas_unlock_irq(&xas);
 
-- 
2.35.1


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Re: [PATCH 14/20] hugetlb: Convert to migrate_folio

[kernel test robot]

Hi "Matthew,

I love your patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v5.19-rc1 next-20220607]
[cannot apply to jaegeuk-f2fs/dev-test trondmy-nfs/linux-next kdave/for-next xfs-linux/for-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/intel-lab-lkp/linux/commits/Matthew-Wilcox-Oracle/Convert-aops-migratepage-to-aops-migrate_folio/20220607-044509
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git f2906aa863381afb0015a9eb7fefad885d4e5a56
config: ia64-randconfig-r015-20220605 (https://download.01.org/0day-ci/archive/20220607/202206071414.41wGG8fp-lkp@intel.com/config)
compiler: ia64-linux-gcc (GCC) 11.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/b038962c9c8c2ab77c71dfba24356ce24bd7a242
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Matthew-Wilcox-Oracle/Convert-aops-migratepage-to-aops-migrate_folio/20220607-044509
        git checkout b038962c9c8c2ab77c71dfba24356ce24bd7a242
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=ia64 SHELL=/bin/bash fs/hugetlbfs/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   fs/hugetlbfs/inode.c: In function 'hugetlbfs_migrate_folio':
>> fs/hugetlbfs/inode.c:990:17: error: implicit declaration of function 'folio_migrate_copy' [-Werror=implicit-function-declaration]
     990 |                 folio_migrate_copy(dst, src);
         |                 ^~~~~~~~~~~~~~~~~~
>> fs/hugetlbfs/inode.c:992:17: error: implicit declaration of function 'folio_migrate_flags'; did you mean 'folio_mapping_flags'? [-Werror=implicit-function-declaration]
     992 |                 folio_migrate_flags(dst, src);
         |                 ^~~~~~~~~~~~~~~~~~~
         |                 folio_mapping_flags
   cc1: some warnings being treated as errors


vim +/folio_migrate_copy +990 fs/hugetlbfs/inode.c

   972	
   973	static int hugetlbfs_migrate_folio(struct address_space *mapping,
   974					struct folio *dst, struct folio *src,
   975					enum migrate_mode mode)
   976	{
   977		int rc;
   978	
   979		rc = migrate_huge_page_move_mapping(mapping, dst, src);
   980		if (rc != MIGRATEPAGE_SUCCESS)
   981			return rc;
   982	
   983		if (hugetlb_page_subpool(&src->page)) {
   984			hugetlb_set_page_subpool(&dst->page,
   985						hugetlb_page_subpool(&src->page));
   986			hugetlb_set_page_subpool(&src->page, NULL);
   987		}
   988	
   989		if (mode != MIGRATE_SYNC_NO_COPY)
 > 990			folio_migrate_copy(dst, src);
   991		else
 > 992			folio_migrate_flags(dst, src);
   993	
   994		return MIGRATEPAGE_SUCCESS;
   995	}
   996	

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp

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Re: [PATCH 14/20] hugetlb: Convert to migrate_folio

[Matthew Wilcox]

On Tue, Jun 07, 2022 at 02:13:26PM +0800, kernel test robot wrote:
>    fs/hugetlbfs/inode.c: In function 'hugetlbfs_migrate_folio':
> >> fs/hugetlbfs/inode.c:990:17: error: implicit declaration of function 'folio_migrate_copy' [-Werror=implicit-function-declaration]
>      990 |                 folio_migrate_copy(dst, src);
>          |                 ^~~~~~~~~~~~~~~~~~
> >> fs/hugetlbfs/inode.c:992:17: error: implicit declaration of function 'folio_migrate_flags'; did you mean 'folio_mapping_flags'? [-Werror=implicit-function-declaration]
>      992 |                 folio_migrate_flags(dst, src);
>          |                 ^~~~~~~~~~~~~~~~~~~
>          |                 folio_mapping_flags
>    cc1: some warnings being treated as errors

Thanks, fixed.

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[PATCH 15/20] balloon: Convert to migrate_folio

[Matthew Wilcox (Oracle)]

This is little more than changing the types over; there's no real work
being done in this function.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/balloon_compaction.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c
index 4b8eab4b3f45..3f75b876ad76 100644
--- a/mm/balloon_compaction.c
+++ b/mm/balloon_compaction.c
@@ -230,11 +230,10 @@ static void balloon_page_putback(struct page *page)
 
 
 /* move_to_new_page() counterpart for a ballooned page */
-static int balloon_page_migrate(struct address_space *mapping,
-		struct page *newpage, struct page *page,
-		enum migrate_mode mode)
+static int balloon_migrate_folio(struct address_space *mapping,
+		struct folio *dst, struct folio *src, enum migrate_mode mode)
 {
-	struct balloon_dev_info *balloon = balloon_page_device(page);
+	struct balloon_dev_info *balloon = balloon_page_device(&src->page);
 
 	/*
 	 * We can not easily support the no copy case here so ignore it as it
@@ -244,14 +243,14 @@ static int balloon_page_migrate(struct address_space *mapping,
 	if (mode == MIGRATE_SYNC_NO_COPY)
 		return -EINVAL;
 
-	VM_BUG_ON_PAGE(!PageLocked(page), page);
-	VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
+	VM_BUG_ON_FOLIO(!folio_test_locked(src), src);
+	VM_BUG_ON_FOLIO(!folio_test_locked(dst), dst);
 
-	return balloon->migratepage(balloon, newpage, page, mode);
+	return balloon->migratepage(balloon, &dst->page, &src->page, mode);
 }
 
 const struct address_space_operations balloon_aops = {
-	.migratepage = balloon_page_migrate,
+	.migrate_folio = balloon_migrate_folio,
 	.isolate_page = balloon_page_isolate,
 	.putback_page = balloon_page_putback,
 };
-- 
2.35.1


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Re: [PATCH 15/20] balloon: Convert to migrate_folio

[David Hildenbrand]

On 06.06.22 22:40, Matthew Wilcox (Oracle) wrote:
> This is little more than changing the types over; there's no real work
> being done in this function.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>  mm/balloon_compaction.c | 15 +++++++--------
>  1 file changed, 7 insertions(+), 8 deletions(-)
> 
> diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c
> index 4b8eab4b3f45..3f75b876ad76 100644
> --- a/mm/balloon_compaction.c
> +++ b/mm/balloon_compaction.c
> @@ -230,11 +230,10 @@ static void balloon_page_putback(struct page *page)
>  
>  
>  /* move_to_new_page() counterpart for a ballooned page */
> -static int balloon_page_migrate(struct address_space *mapping,
> -		struct page *newpage, struct page *page,
> -		enum migrate_mode mode)
> +static int balloon_migrate_folio(struct address_space *mapping,
> +		struct folio *dst, struct folio *src, enum migrate_mode mode)
>  {
> -	struct balloon_dev_info *balloon = balloon_page_device(page);
> +	struct balloon_dev_info *balloon = balloon_page_device(&src->page);
>  
>  	/*
>  	 * We can not easily support the no copy case here so ignore it as it
> @@ -244,14 +243,14 @@ static int balloon_page_migrate(struct address_space *mapping,
>  	if (mode == MIGRATE_SYNC_NO_COPY)
>  		return -EINVAL;
>  
> -	VM_BUG_ON_PAGE(!PageLocked(page), page);
> -	VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
> +	VM_BUG_ON_FOLIO(!folio_test_locked(src), src);
> +	VM_BUG_ON_FOLIO(!folio_test_locked(dst), dst);
>  
> -	return balloon->migratepage(balloon, newpage, page, mode);
> +	return balloon->migratepage(balloon, &dst->page, &src->page, mode);
>  }
>  
>  const struct address_space_operations balloon_aops = {
> -	.migratepage = balloon_page_migrate,
> +	.migrate_folio = balloon_migrate_folio,
>  	.isolate_page = balloon_page_isolate,
>  	.putback_page = balloon_page_putback,
>  };

I assume you're working on conversion of the other callbacks as well,
because otherwise, this ends up looking a bit inconsistent and confusing :)

Change LGTM.

-- 
Thanks,

David / dhildenb


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Re: [PATCH 15/20] balloon: Convert to migrate_folio

[Matthew Wilcox]

On Tue, Jun 07, 2022 at 09:36:21AM +0200, David Hildenbrand wrote:
> On 06.06.22 22:40, Matthew Wilcox (Oracle) wrote:
> >  const struct address_space_operations balloon_aops = {
> > -	.migratepage = balloon_page_migrate,
> > +	.migrate_folio = balloon_migrate_folio,
> >  	.isolate_page = balloon_page_isolate,
> >  	.putback_page = balloon_page_putback,
> >  };
> 
> I assume you're working on conversion of the other callbacks as well,
> because otherwise, this ends up looking a bit inconsistent and confusing :)

My intention was to finish converting aops for the next merge window.

However, it seems to me that we goofed back in 2016 by merging
commit bda807d44454.  isolate_page() and putback_page() should
never have been part of address_space_operations.

I'm about to embark on creating a new migrate_operations struct
for drivers to use that contains only isolate/putback/migrate.
No filesystem uses isolate/putback, so those can just be deleted.
Both migrate_operations & address_space_operations will contain a
migrate callback.

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Re: [PATCH 15/20] balloon: Convert to migrate_folio

[Matthew Wilcox]

On Tue, Jun 07, 2022 at 03:24:15PM +0100, Matthew Wilcox wrote:
> On Tue, Jun 07, 2022 at 09:36:21AM +0200, David Hildenbrand wrote:
> > On 06.06.22 22:40, Matthew Wilcox (Oracle) wrote:
> > >  const struct address_space_operations balloon_aops = {
> > > -	.migratepage = balloon_page_migrate,
> > > +	.migrate_folio = balloon_migrate_folio,
> > >  	.isolate_page = balloon_page_isolate,
> > >  	.putback_page = balloon_page_putback,
> > >  };
> > 
> > I assume you're working on conversion of the other callbacks as well,
> > because otherwise, this ends up looking a bit inconsistent and confusing :)
> 
> My intention was to finish converting aops for the next merge window.
> 
> However, it seems to me that we goofed back in 2016 by merging
> commit bda807d44454.  isolate_page() and putback_page() should
> never have been part of address_space_operations.
> 
> I'm about to embark on creating a new migrate_operations struct
> for drivers to use that contains only isolate/putback/migrate.
> No filesystem uses isolate/putback, so those can just be deleted.
> Both migrate_operations & address_space_operations will contain a
> migrate callback.

Well, that went more smoothly than I thought it would.

I can't see a nice way to split this patch up (other than making secretmem
its own patch).  We just don't have enough bits in struct page to support
both ways of handling PageMovable at the same time, so we can't convert
one driver at a time.  The diffstat is pretty compelling.

The patch is on top of this patch series; I think it probably makes
sense to shuffle it to be first, to avoid changing these drivers to
folios, then changing them back.

Questions:

Is what I've done with zsmalloc acceptable?  The locking in that
file is rather complex.

Can we now eliminate balloon_mnt / balloon_fs from cmm.c?  I haven't even
compiled thatfile , but it seems like the filesystem serves no use now.

Similar question for vmw_balloon.c, although I have compiled that.

---

I just spotted a bug with zs_unregister_migration(); it won't compile
without CONFIG_MIGRATION.  I'll fix that up if the general approach is
acceptable.

 arch/powerpc/platforms/pseries/cmm.c |   13 --------
 drivers/misc/vmw_balloon.c           |   10 ------
 include/linux/balloon_compaction.h   |    6 +---
 include/linux/fs.h                   |    2 -
 include/linux/migrate.h              |   27 ++++++++++++++----
 include/linux/page-flags.h           |    2 -
 mm/balloon_compaction.c              |   18 ++++++------
 mm/compaction.c                      |   29 ++++++++-----------
 mm/migrate.c                         |   23 ++++++++-------
 mm/secretmem.c                       |    6 ----
 mm/util.c                            |    4 +-
 mm/z3fold.c                          |   45 ++++++------------------------
 mm/zsmalloc.c                        |   52 +++++++++--------------------------
 13 files changed, 83 insertions(+), 154 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/cmm.c b/arch/powerpc/platforms/pseries/cmm.c
index 15ed8206c463..2ecbab3db723 100644
--- a/arch/powerpc/platforms/pseries/cmm.c
+++ b/arch/powerpc/platforms/pseries/cmm.c
@@ -578,23 +578,10 @@ static int cmm_balloon_compaction_init(void)
 		return rc;
 	}
 
-	b_dev_info.inode = alloc_anon_inode(balloon_mnt->mnt_sb);
-	if (IS_ERR(b_dev_info.inode)) {
-		rc = PTR_ERR(b_dev_info.inode);
-		b_dev_info.inode = NULL;
-		kern_unmount(balloon_mnt);
-		balloon_mnt = NULL;
-		return rc;
-	}
-
-	b_dev_info.inode->i_mapping->a_ops = &balloon_aops;
 	return 0;
 }
 static void cmm_balloon_compaction_deinit(void)
 {
-	if (b_dev_info.inode)
-		iput(b_dev_info.inode);
-	b_dev_info.inode = NULL;
 	kern_unmount(balloon_mnt);
 	balloon_mnt = NULL;
 }
diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index 086ce77d9074..4a6755934bb5 100644
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -1869,10 +1869,6 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info,
  */
 static void vmballoon_compaction_deinit(struct vmballoon *b)
 {
-	if (!IS_ERR(b->b_dev_info.inode))
-		iput(b->b_dev_info.inode);
-
-	b->b_dev_info.inode = NULL;
 	kern_unmount(vmballoon_mnt);
 	vmballoon_mnt = NULL;
 }
@@ -1895,12 +1891,6 @@ static __init int vmballoon_compaction_init(struct vmballoon *b)
 		return PTR_ERR(vmballoon_mnt);
 
 	b->b_dev_info.migratepage = vmballoon_migratepage;
-	b->b_dev_info.inode = alloc_anon_inode(vmballoon_mnt->mnt_sb);
-
-	if (IS_ERR(b->b_dev_info.inode))
-		return PTR_ERR(b->b_dev_info.inode);
-
-	b->b_dev_info.inode->i_mapping->a_ops = &balloon_aops;
 	return 0;
 }
 
diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_compaction.h
index edb7f6d41faa..5ca2d5699620 100644
--- a/include/linux/balloon_compaction.h
+++ b/include/linux/balloon_compaction.h
@@ -57,7 +57,6 @@ struct balloon_dev_info {
 	struct list_head pages;		/* Pages enqueued & handled to Host */
 	int (*migratepage)(struct balloon_dev_info *, struct page *newpage,
 			struct page *page, enum migrate_mode mode);
-	struct inode *inode;
 };
 
 extern struct page *balloon_page_alloc(void);
@@ -75,11 +74,10 @@ static inline void balloon_devinfo_init(struct balloon_dev_info *balloon)
 	spin_lock_init(&balloon->pages_lock);
 	INIT_LIST_HEAD(&balloon->pages);
 	balloon->migratepage = NULL;
-	balloon->inode = NULL;
 }
 
 #ifdef CONFIG_BALLOON_COMPACTION
-extern const struct address_space_operations balloon_aops;
+extern const struct movable_operations balloon_mops;
 
 /*
  * balloon_page_insert - insert a page into the balloon's page list and make
@@ -94,7 +92,7 @@ static inline void balloon_page_insert(struct balloon_dev_info *balloon,
 				       struct page *page)
 {
 	__SetPageOffline(page);
-	__SetPageMovable(page, balloon->inode->i_mapping);
+	__SetPageMovable(page, &balloon_mops);
 	set_page_private(page, (unsigned long)balloon);
 	list_add(&page->lru, &balloon->pages);
 }
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 95347cc035ae..7e06919b8f60 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -367,8 +367,6 @@ struct address_space_operations {
 	 */
 	int (*migrate_folio)(struct address_space *, struct folio *dst,
 			struct folio *src, enum migrate_mode);
-	bool (*isolate_page)(struct page *, isolate_mode_t);
-	void (*putback_page)(struct page *);
 	int (*launder_folio)(struct folio *);
 	bool (*is_partially_uptodate) (struct folio *, size_t from,
 			size_t count);
diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 4670f3aec232..27f3780fac36 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -19,6 +19,13 @@ struct migration_target_control;
  */
 #define MIGRATEPAGE_SUCCESS		0
 
+struct movable_operations {
+	bool (*isolate_page)(struct page *, isolate_mode_t);
+	int (*migrate_page)(struct page *dst, struct page *src,
+			enum migrate_mode);
+	void (*putback_page)(struct page *);
+};
+
 /* Defined in mm/debug.c: */
 extern const char *migrate_reason_names[MR_TYPES];
 
@@ -79,13 +86,13 @@ static inline int next_demotion_node(int node)
 #endif
 
 #ifdef CONFIG_COMPACTION
-extern int PageMovable(struct page *page);
-extern void __SetPageMovable(struct page *page, struct address_space *mapping);
-extern void __ClearPageMovable(struct page *page);
+bool PageMovable(struct page *page);
+void __SetPageMovable(struct page *page, const struct movable_operations *ops);
+void __ClearPageMovable(struct page *page);
 #else
-static inline int PageMovable(struct page *page) { return 0; }
+static inline bool PageMovable(struct page *page) { return false; }
 static inline void __SetPageMovable(struct page *page,
-				struct address_space *mapping)
+		const struct movable_operations *ops)
 {
 }
 static inline void __ClearPageMovable(struct page *page)
@@ -98,6 +105,15 @@ static inline bool folio_test_movable(struct folio *folio)
 	return PageMovable(&folio->page);
 }
 
+static inline
+const struct movable_operations *page_movable_ops(struct page *page)
+{
+	VM_BUG_ON(!__PageMovable(page));
+
+	return (const struct movable_operations *)
+		((unsigned long)page->mapping - PAGE_MAPPING_MOVABLE);
+}
+
 #ifdef CONFIG_NUMA_BALANCING
 extern int migrate_misplaced_page(struct page *page,
 				  struct vm_area_struct *vma, int node);
@@ -171,5 +187,4 @@ int migrate_vma_setup(struct migrate_vma *args);
 void migrate_vma_pages(struct migrate_vma *migrate);
 void migrate_vma_finalize(struct migrate_vma *migrate);
 #endif /* CONFIG_MIGRATION */
-
 #endif /* _LINUX_MIGRATE_H */
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index e66f7aa3191d..3f5490f6f038 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -639,7 +639,7 @@ __PAGEFLAG(Reported, reported, PF_NO_COMPOUND)
  * structure which KSM associates with that merged page.  See ksm.h.
  *
  * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is used for non-lru movable
- * page and then page->mapping points a struct address_space.
+ * page and then page->mapping points to a struct movable_operations.
  *
  * Please note that, confusingly, "page_mapping" refers to the inode
  * address_space which maps the page from disk; whereas "page_mapped"
diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c
index 3f75b876ad76..7d1eb90ed07a 100644
--- a/mm/balloon_compaction.c
+++ b/mm/balloon_compaction.c
@@ -230,10 +230,10 @@ static void balloon_page_putback(struct page *page)
 
 
 /* move_to_new_page() counterpart for a ballooned page */
-static int balloon_migrate_folio(struct address_space *mapping,
-		struct folio *dst, struct folio *src, enum migrate_mode mode)
+static int balloon_migrate_page(struct page *dst, struct page *src,
+		enum migrate_mode mode)
 {
-	struct balloon_dev_info *balloon = balloon_page_device(&src->page);
+	struct balloon_dev_info *balloon = balloon_page_device(src);
 
 	/*
 	 * We can not easily support the no copy case here so ignore it as it
@@ -243,17 +243,17 @@ static int balloon_migrate_folio(struct address_space *mapping,
 	if (mode == MIGRATE_SYNC_NO_COPY)
 		return -EINVAL;
 
-	VM_BUG_ON_FOLIO(!folio_test_locked(src), src);
-	VM_BUG_ON_FOLIO(!folio_test_locked(dst), dst);
+	VM_BUG_ON_PAGE(!PageLocked(src), src);
+	VM_BUG_ON_PAGE(!PageLocked(dst), dst);
 
-	return balloon->migratepage(balloon, &dst->page, &src->page, mode);
+	return balloon->migratepage(balloon, dst, src, mode);
 }
 
-const struct address_space_operations balloon_aops = {
-	.migrate_folio = balloon_migrate_folio,
+const struct movable_operations balloon_mops = {
+	.migrate_page = balloon_migrate_page,
 	.isolate_page = balloon_page_isolate,
 	.putback_page = balloon_page_putback,
 };
-EXPORT_SYMBOL_GPL(balloon_aops);
+EXPORT_SYMBOL_GPL(balloon_mops);
 
 #endif /* CONFIG_BALLOON_COMPACTION */
diff --git a/mm/compaction.c b/mm/compaction.c
index f0dc62159c0e..a2c53fcf933e 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -110,28 +110,27 @@ static void split_map_pages(struct list_head *list)
 }
 
 #ifdef CONFIG_COMPACTION
-
-int PageMovable(struct page *page)
+bool PageMovable(struct page *page)
 {
-	struct address_space *mapping;
+	const struct movable_operations *mops;
 
 	VM_BUG_ON_PAGE(!PageLocked(page), page);
 	if (!__PageMovable(page))
-		return 0;
+		return false;
 
-	mapping = page_mapping(page);
-	if (mapping && mapping->a_ops && mapping->a_ops->isolate_page)
-		return 1;
+	mops = page_movable_ops(page);
+	if (mops)
+		return true;
 
-	return 0;
+	return false;
 }
 EXPORT_SYMBOL(PageMovable);
 
-void __SetPageMovable(struct page *page, struct address_space *mapping)
+void __SetPageMovable(struct page *page, const struct movable_operations *mops)
 {
 	VM_BUG_ON_PAGE(!PageLocked(page), page);
-	VM_BUG_ON_PAGE((unsigned long)mapping & PAGE_MAPPING_MOVABLE, page);
-	page->mapping = (void *)((unsigned long)mapping | PAGE_MAPPING_MOVABLE);
+	VM_BUG_ON_PAGE((unsigned long)mops & PAGE_MAPPING_MOVABLE, page);
+	page->mapping = (void *)((unsigned long)mops | PAGE_MAPPING_MOVABLE);
 }
 EXPORT_SYMBOL(__SetPageMovable);
 
@@ -139,12 +138,10 @@ void __ClearPageMovable(struct page *page)
 {
 	VM_BUG_ON_PAGE(!PageMovable(page), page);
 	/*
-	 * Clear registered address_space val with keeping PAGE_MAPPING_MOVABLE
-	 * flag so that VM can catch up released page by driver after isolation.
-	 * With it, VM migration doesn't try to put it back.
+	 * This page still has the type of a movable page, but it's
+	 * actually not movable any more.
 	 */
-	page->mapping = (void *)((unsigned long)page->mapping &
-				PAGE_MAPPING_MOVABLE);
+	page->mapping = (void *)PAGE_MAPPING_MOVABLE;
 }
 EXPORT_SYMBOL(__ClearPageMovable);
 
diff --git a/mm/migrate.c b/mm/migrate.c
index 53fcfa5d55b8..a13e17ab72c8 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -59,7 +59,7 @@
 
 int isolate_movable_page(struct page *page, isolate_mode_t mode)
 {
-	struct address_space *mapping;
+	const struct movable_operations *mops;
 
 	/*
 	 * Avoid burning cycles with pages that are yet under __free_pages(),
@@ -97,10 +97,10 @@ int isolate_movable_page(struct page *page, isolate_mode_t mode)
 	if (!PageMovable(page) || PageIsolated(page))
 		goto out_no_isolated;
 
-	mapping = page_mapping(page);
-	VM_BUG_ON_PAGE(!mapping, page);
+	mops = page_movable_ops(page);
+	VM_BUG_ON_PAGE(!mops, page);
 
-	if (!mapping->a_ops->isolate_page(page, mode))
+	if (!mops->isolate_page(page, mode))
 		goto out_no_isolated;
 
 	/* Driver shouldn't use PG_isolated bit of page->flags */
@@ -120,10 +120,9 @@ int isolate_movable_page(struct page *page, isolate_mode_t mode)
 
 static void putback_movable_page(struct page *page)
 {
-	struct address_space *mapping;
+	const struct movable_operations *mops = page_movable_ops(page);
 
-	mapping = page_mapping(page);
-	mapping->a_ops->putback_page(page);
+	mops->putback_page(page);
 	ClearPageIsolated(page);
 }
 
@@ -889,16 +888,15 @@ static int fallback_migrate_folio(struct address_space *mapping,
 static int move_to_new_folio(struct folio *dst, struct folio *src,
 				enum migrate_mode mode)
 {
-	struct address_space *mapping;
 	int rc = -EAGAIN;
 	bool is_lru = !__PageMovable(&src->page);
 
 	VM_BUG_ON_FOLIO(!folio_test_locked(src), src);
 	VM_BUG_ON_FOLIO(!folio_test_locked(dst), dst);
 
-	mapping = folio_mapping(src);
-
 	if (likely(is_lru)) {
+		struct address_space *mapping = folio_mapping(src);
+
 		if (!mapping)
 			rc = migrate_folio(mapping, dst, src, mode);
 		else if (mapping->a_ops->migrate_folio)
@@ -914,6 +912,8 @@ static int move_to_new_folio(struct folio *dst, struct folio *src,
 		else
 			rc = fallback_migrate_folio(mapping, dst, src, mode);
 	} else {
+		const struct movable_operations *mops;
+
 		/*
 		 * In case of non-lru page, it could be released after
 		 * isolation step. In that case, we shouldn't try migration.
@@ -925,7 +925,8 @@ static int move_to_new_folio(struct folio *dst, struct folio *src,
 			goto out;
 		}
 
-		rc = mapping->a_ops->migrate_folio(mapping, dst, src, mode);
+		mops = page_movable_ops(&src->page);
+		rc = mops->migrate_page(&dst->page, &src->page, mode);
 		WARN_ON_ONCE(rc == MIGRATEPAGE_SUCCESS &&
 				!folio_test_isolated(src));
 	}
diff --git a/mm/secretmem.c b/mm/secretmem.c
index 9c7f6e3bf3e1..43bebf703cf9 100644
--- a/mm/secretmem.c
+++ b/mm/secretmem.c
@@ -133,11 +133,6 @@ static const struct file_operations secretmem_fops = {
 	.mmap		= secretmem_mmap,
 };
 
-static bool secretmem_isolate_page(struct page *page, isolate_mode_t mode)
-{
-	return false;
-}
-
 static int secretmem_migrate_folio(struct address_space *mapping,
 				 struct folio *dst, struct folio *src,
 				 enum migrate_mode mode)
@@ -155,7 +150,6 @@ const struct address_space_operations secretmem_aops = {
 	.dirty_folio	= noop_dirty_folio,
 	.free_folio	= secretmem_free_folio,
 	.migrate_folio	= secretmem_migrate_folio,
-	.isolate_page	= secretmem_isolate_page,
 };
 
 static int secretmem_setattr(struct user_namespace *mnt_userns,
diff --git a/mm/util.c b/mm/util.c
index 0837570c9225..53af0e79d3e4 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -804,10 +804,10 @@ struct address_space *folio_mapping(struct folio *folio)
 		return swap_address_space(folio_swap_entry(folio));
 
 	mapping = folio->mapping;
-	if ((unsigned long)mapping & PAGE_MAPPING_ANON)
+	if ((unsigned long)mapping & PAGE_MAPPING_FLAGS)
 		return NULL;
 
-	return (void *)((unsigned long)mapping & ~PAGE_MAPPING_FLAGS);
+	return mapping;
 }
 EXPORT_SYMBOL(folio_mapping);
 
diff --git a/mm/z3fold.c b/mm/z3fold.c
index 5d091c41fb35..4883e3f573b5 100644
--- a/mm/z3fold.c
+++ b/mm/z3fold.c
@@ -149,7 +149,6 @@ struct z3fold_header {
  * @compact_wq:	workqueue for page layout background optimization
  * @release_wq:	workqueue for safe page release
  * @work:	work_struct for safe page release
- * @inode:	inode for z3fold pseudo filesystem
  *
  * This structure is allocated at pool creation time and maintains metadata
  * pertaining to a particular z3fold pool.
@@ -169,7 +168,6 @@ struct z3fold_pool {
 	struct workqueue_struct *compact_wq;
 	struct workqueue_struct *release_wq;
 	struct work_struct work;
-	struct inode *inode;
 };
 
 /*
@@ -362,26 +360,6 @@ static void z3fold_unmount(void)
 	kern_unmount(z3fold_mnt);
 }
 
-static const struct address_space_operations z3fold_aops;
-static int z3fold_register_migration(struct z3fold_pool *pool)
-{
-	pool->inode = alloc_anon_inode(z3fold_mnt->mnt_sb);
-	if (IS_ERR(pool->inode)) {
-		pool->inode = NULL;
-		return 1;
-	}
-
-	pool->inode->i_mapping->private_data = pool;
-	pool->inode->i_mapping->a_ops = &z3fold_aops;
-	return 0;
-}
-
-static void z3fold_unregister_migration(struct z3fold_pool *pool)
-{
-	if (pool->inode)
-		iput(pool->inode);
-}
-
 /* Initializes the z3fold header of a newly allocated z3fold page */
 static struct z3fold_header *init_z3fold_page(struct page *page, bool headless,
 					struct z3fold_pool *pool, gfp_t gfp)
@@ -1002,14 +980,10 @@ static struct z3fold_pool *z3fold_create_pool(const char *name, gfp_t gfp,
 	pool->release_wq = create_singlethread_workqueue(pool->name);
 	if (!pool->release_wq)
 		goto out_wq;
-	if (z3fold_register_migration(pool))
-		goto out_rwq;
 	INIT_WORK(&pool->work, free_pages_work);
 	pool->ops = ops;
 	return pool;
 
-out_rwq:
-	destroy_workqueue(pool->release_wq);
 out_wq:
 	destroy_workqueue(pool->compact_wq);
 out_unbuddied:
@@ -1043,11 +1017,12 @@ static void z3fold_destroy_pool(struct z3fold_pool *pool)
 
 	destroy_workqueue(pool->compact_wq);
 	destroy_workqueue(pool->release_wq);
-	z3fold_unregister_migration(pool);
 	free_percpu(pool->unbuddied);
 	kfree(pool);
 }
 
+static const struct movable_operations z3fold_mops;
+
 /**
  * z3fold_alloc() - allocates a region of a given size
  * @pool:	z3fold pool from which to allocate
@@ -1117,11 +1092,11 @@ static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp,
 	}
 	if (can_sleep) {
 		lock_page(page);
-		__SetPageMovable(page, pool->inode->i_mapping);
+		__SetPageMovable(page, &z3fold_mops);
 		unlock_page(page);
 	} else {
 		WARN_ON(!trylock_page(page));
-		__SetPageMovable(page, pool->inode->i_mapping);
+		__SetPageMovable(page, &z3fold_mops);
 		unlock_page(page);
 	}
 	z3fold_page_lock(zhdr);
@@ -1554,11 +1529,9 @@ static bool z3fold_page_isolate(struct page *page, isolate_mode_t mode)
 	return false;
 }
 
-static int z3fold_migrate_folio(struct address_space *mapping,
-		struct folio *dst, struct folio *src, enum migrate_mode mode)
+static int z3fold_migrate_page(struct page *newpage, struct page *page,
+		enum migrate_mode mode)
 {
-	struct page *newpage = &dst->page;
-	struct page *page = &src->page;
 	struct z3fold_header *zhdr, *new_zhdr;
 	struct z3fold_pool *pool;
 	struct address_space *new_mapping;
@@ -1610,7 +1583,7 @@ static int z3fold_migrate_folio(struct address_space *mapping,
 	spin_lock(&pool->lock);
 	list_add(&newpage->lru, &pool->lru);
 	spin_unlock(&pool->lock);
-	__SetPageMovable(newpage, new_mapping);
+	__SetPageMovable(newpage, &z3fold_mops);
 	z3fold_page_unlock(new_zhdr);
 
 	queue_work_on(new_zhdr->cpu, pool->compact_wq, &new_zhdr->work);
@@ -1644,9 +1617,9 @@ static void z3fold_page_putback(struct page *page)
 	z3fold_page_unlock(zhdr);
 }
 
-static const struct address_space_operations z3fold_aops = {
+static const struct movable_operations z3fold_mops = {
 	.isolate_page = z3fold_page_isolate,
-	.migrate_folio = z3fold_migrate_folio,
+	.migrate_page = z3fold_migrate_page,
 	.putback_page = z3fold_page_putback,
 };
 
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 8ed79121195a..582765115289 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -252,7 +252,6 @@ struct zs_pool {
 	struct dentry *stat_dentry;
 #endif
 #ifdef CONFIG_COMPACTION
-	struct inode *inode;
 	struct work_struct free_work;
 #endif
 	/* protect page/zspage migration */
@@ -271,6 +270,7 @@ struct zspage {
 	unsigned int freeobj;
 	struct page *first_page;
 	struct list_head list; /* fullness list */
+	struct zs_pool *pool;
 #ifdef CONFIG_COMPACTION
 	rwlock_t lock;
 #endif
@@ -295,8 +295,6 @@ static bool ZsHugePage(struct zspage *zspage)
 }
 
 #ifdef CONFIG_COMPACTION
-static int zs_register_migration(struct zs_pool *pool);
-static void zs_unregister_migration(struct zs_pool *pool);
 static void migrate_lock_init(struct zspage *zspage);
 static void migrate_read_lock(struct zspage *zspage);
 static void migrate_read_unlock(struct zspage *zspage);
@@ -309,8 +307,6 @@ static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage);
 #else
 static int zsmalloc_mount(void) { return 0; }
 static void zsmalloc_unmount(void) {}
-static int zs_register_migration(struct zs_pool *pool) { return 0; }
-static void zs_unregister_migration(struct zs_pool *pool) {}
 static void migrate_lock_init(struct zspage *zspage) {}
 static void migrate_read_lock(struct zspage *zspage) {}
 static void migrate_read_unlock(struct zspage *zspage) {}
@@ -1083,6 +1079,7 @@ static struct zspage *alloc_zspage(struct zs_pool *pool,
 
 	create_page_chain(class, zspage, pages);
 	init_zspage(class, zspage);
+	zspage->pool = pool;
 
 	return zspage;
 }
@@ -1823,6 +1820,8 @@ static void dec_zspage_isolation(struct zspage *zspage)
 	zspage->isolated--;
 }
 
+static const struct movable_operations zsmalloc_mops;
+
 static void replace_sub_page(struct size_class *class, struct zspage *zspage,
 				struct page *newpage, struct page *oldpage)
 {
@@ -1843,7 +1842,7 @@ static void replace_sub_page(struct size_class *class, struct zspage *zspage,
 	set_first_obj_offset(newpage, get_first_obj_offset(oldpage));
 	if (unlikely(ZsHugePage(zspage)))
 		newpage->index = oldpage->index;
-	__SetPageMovable(newpage, page_mapping(oldpage));
+	__SetPageMovable(newpage, &zsmalloc_mops);
 }
 
 static bool zs_page_isolate(struct page *page, isolate_mode_t mode)
@@ -1865,11 +1864,9 @@ static bool zs_page_isolate(struct page *page, isolate_mode_t mode)
 	return true;
 }
 
-static int zs_migrate_folio(struct address_space *mapping,
-		struct folio *dst, struct folio *src, enum migrate_mode mode)
+static int zs_migrate_page(struct page *newpage, struct page *page,
+		enum migrate_mode mode)
 {
-	struct page *newpage = &dst->page;
-	struct page *page = &src->page;
 	struct zs_pool *pool;
 	struct size_class *class;
 	struct zspage *zspage;
@@ -1891,14 +1888,15 @@ static int zs_migrate_folio(struct address_space *mapping,
 	VM_BUG_ON_PAGE(!PageMovable(page), page);
 	VM_BUG_ON_PAGE(!PageIsolated(page), page);
 
-	pool = mapping->private_data;
+	/* The page is locked, so this pointer must remain valid */
+	zspage = get_zspage(page);
+	pool = zspage->pool;
 
 	/*
 	 * The pool migrate_lock protects the race between zpage migration
 	 * and zs_free.
 	 */
 	write_lock(&pool->migrate_lock);
-	zspage = get_zspage(page);
 	class = zspage_class(pool, zspage);
 
 	/*
@@ -1966,31 +1964,12 @@ static void zs_page_putback(struct page *page)
 	migrate_write_unlock(zspage);
 }
 
-static const struct address_space_operations zsmalloc_aops = {
+static const struct movable_operations zsmalloc_mops = {
 	.isolate_page = zs_page_isolate,
-	.migrate_folio = zs_migrate_folio,
+	.migrate_page = zs_migrate_page,
 	.putback_page = zs_page_putback,
 };
 
-static int zs_register_migration(struct zs_pool *pool)
-{
-	pool->inode = alloc_anon_inode(zsmalloc_mnt->mnt_sb);
-	if (IS_ERR(pool->inode)) {
-		pool->inode = NULL;
-		return 1;
-	}
-
-	pool->inode->i_mapping->private_data = pool;
-	pool->inode->i_mapping->a_ops = &zsmalloc_aops;
-	return 0;
-}
-
-static void zs_unregister_migration(struct zs_pool *pool)
-{
-	flush_work(&pool->free_work);
-	iput(pool->inode);
-}
-
 /*
  * Caller should hold page_lock of all pages in the zspage
  * In here, we cannot use zspage meta data.
@@ -2045,7 +2024,7 @@ static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage)
 
 	do {
 		WARN_ON(!trylock_page(page));
-		__SetPageMovable(page, pool->inode->i_mapping);
+		__SetPageMovable(page, &zsmalloc_mops);
 		unlock_page(page);
 	} while ((page = get_next_page(page)) != NULL);
 }
@@ -2326,9 +2305,6 @@ struct zs_pool *zs_create_pool(const char *name)
 	/* debug only, don't abort if it fails */
 	zs_pool_stat_create(pool, name);
 
-	if (zs_register_migration(pool))
-		goto err;
-
 	/*
 	 * Not critical since shrinker is only used to trigger internal
 	 * defragmentation of the pool which is pretty optional thing.  If
@@ -2350,7 +2326,7 @@ void zs_destroy_pool(struct zs_pool *pool)
 	int i;
 
 	zs_unregister_shrinker(pool);
-	zs_unregister_migration(pool);
+	flush_work(&pool->free_work);
 	zs_pool_stat_destroy(pool);
 
 	for (i = 0; i < ZS_SIZE_CLASSES; i++) {

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH 15/20] balloon: Convert to migrate_folio

[David Hildenbrand]

On 07.06.22 21:21, Matthew Wilcox wrote:
> On Tue, Jun 07, 2022 at 03:24:15PM +0100, Matthew Wilcox wrote:
>> On Tue, Jun 07, 2022 at 09:36:21AM +0200, David Hildenbrand wrote:
>>> On 06.06.22 22:40, Matthew Wilcox (Oracle) wrote:
>>>>  const struct address_space_operations balloon_aops = {
>>>> -	.migratepage = balloon_page_migrate,
>>>> +	.migrate_folio = balloon_migrate_folio,
>>>>  	.isolate_page = balloon_page_isolate,
>>>>  	.putback_page = balloon_page_putback,
>>>>  };
>>>
>>> I assume you're working on conversion of the other callbacks as well,
>>> because otherwise, this ends up looking a bit inconsistent and confusing :)
>>
>> My intention was to finish converting aops for the next merge window.
>>
>> However, it seems to me that we goofed back in 2016 by merging
>> commit bda807d44454.  isolate_page() and putback_page() should
>> never have been part of address_space_operations.
>>
>> I'm about to embark on creating a new migrate_operations struct
>> for drivers to use that contains only isolate/putback/migrate.
>> No filesystem uses isolate/putback, so those can just be deleted.
>> Both migrate_operations & address_space_operations will contain a
>> migrate callback.

That makes sense to me. I wonder if there was a design
decision/discussion behind that. CCing Rafael.

@Rafael, full mail at

https://lkml.kernel.org/r/Yp+lU55H4igaV3pB@casper.infradead.org

> 
> Well, that went more smoothly than I thought it would.
> 
> I can't see a nice way to split this patch up (other than making secretmem
> its own patch).  We just don't have enough bits in struct page to support
> both ways of handling PageMovable at the same time, so we can't convert
> one driver at a time.  The diffstat is pretty compelling.

Yes, splitting rather overcomplicates stuff.

> 
> The patch is on top of this patch series; I think it probably makes
> sense to shuffle it to be first, to avoid changing these drivers to
> folios, then changing them back.

Absolutely.

> 
> Questions:
> 
> Is what I've done with zsmalloc acceptable?  The locking in that
> file is rather complex.
> 
> Can we now eliminate balloon_mnt / balloon_fs from cmm.c?  I haven't even
> compiled thatfile , but it seems like the filesystem serves no use now.
> 
> Similar question for vmw_balloon.c, although I have compiled that.

IIRC, virtio-balloon, cmm and vmw_balloon all have the mnt/fs just for
page migration purposes. So if one can get rid of them, all should be
able to get rid of them. Essentially everything that uses the balloon
compaction framework.

That should go into separate patches then.

> 
> ---
> 
> I just spotted a bug with zs_unregister_migration(); it won't compile
> without CONFIG_MIGRATION.  I'll fix that up if the general approach is
> acceptable.
> 
>  arch/powerpc/platforms/pseries/cmm.c |   13 --------
>  drivers/misc/vmw_balloon.c           |   10 ------
>  include/linux/balloon_compaction.h   |    6 +---
>  include/linux/fs.h                   |    2 -
>  include/linux/migrate.h              |   27 ++++++++++++++----
>  include/linux/page-flags.h           |    2 -
>  mm/balloon_compaction.c              |   18 ++++++------
>  mm/compaction.c                      |   29 ++++++++-----------
>  mm/migrate.c                         |   23 ++++++++-------
>  mm/secretmem.c                       |    6 ----
>  mm/util.c                            |    4 +-
>  mm/z3fold.c                          |   45 ++++++------------------------
>  mm/zsmalloc.c                        |   52 +++++++++--------------------------
>  13 files changed, 83 insertions(+), 154 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/pseries/cmm.c b/arch/powerpc/platforms/pseries/cmm.c
> index 15ed8206c463..2ecbab3db723 100644
> --- a/arch/powerpc/platforms/pseries/cmm.c
> +++ b/arch/powerpc/platforms/pseries/cmm.c
> @@ -578,23 +578,10 @@ static int cmm_balloon_compaction_init(void)
>  		return rc;
>  	}
>  
> -	b_dev_info.inode = alloc_anon_inode(balloon_mnt->mnt_sb);
> -	if (IS_ERR(b_dev_info.inode)) {
> -		rc = PTR_ERR(b_dev_info.inode);
> -		b_dev_info.inode = NULL;
> -		kern_unmount(balloon_mnt);
> -		balloon_mnt = NULL;
> -		return rc;
> -	}
> -
> -	b_dev_info.inode->i_mapping->a_ops = &balloon_aops;


Are you missing similar updates to drivers/virtio/virtio_balloon.c ?

At least, there we're also using balloon_aops, so this patch shouldn't
compile.


Skimming over it, nothing else jumped at me.

-- 
Thanks,

David / dhildenb


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Re: [PATCH 15/20] balloon: Convert to migrate_folio

[Rafael Aquini]

On Wed, Jun 08, 2022 at 11:59:31AM +0200, David Hildenbrand wrote:
> On 07.06.22 21:21, Matthew Wilcox wrote:
> > On Tue, Jun 07, 2022 at 03:24:15PM +0100, Matthew Wilcox wrote:
> >> On Tue, Jun 07, 2022 at 09:36:21AM +0200, David Hildenbrand wrote:
> >>> On 06.06.22 22:40, Matthew Wilcox (Oracle) wrote:
> >>>>  const struct address_space_operations balloon_aops = {
> >>>> -	.migratepage = balloon_page_migrate,
> >>>> +	.migrate_folio = balloon_migrate_folio,
> >>>>  	.isolate_page = balloon_page_isolate,
> >>>>  	.putback_page = balloon_page_putback,
> >>>>  };
> >>>
> >>> I assume you're working on conversion of the other callbacks as well,
> >>> because otherwise, this ends up looking a bit inconsistent and confusing :)
> >>
> >> My intention was to finish converting aops for the next merge window.
> >>
> >> However, it seems to me that we goofed back in 2016 by merging
> >> commit bda807d44454.  isolate_page() and putback_page() should
> >> never have been part of address_space_operations.
> >>
> >> I'm about to embark on creating a new migrate_operations struct
> >> for drivers to use that contains only isolate/putback/migrate.
> >> No filesystem uses isolate/putback, so those can just be deleted.
> >> Both migrate_operations & address_space_operations will contain a
> >> migrate callback.
> 
> That makes sense to me. I wonder if there was a design
> decision/discussion behind that. CCing Rafael.
>

None that I recollect. If memory still serves me, I think the idea behind
bda807d44454 and friends was to provide a generic way to allow page
mobility for drivers without adding complexity to the page isolation / putback
paths, and since the migration callback was already part of the aops struct
those new callbacks just followed suit.


-- Rafael


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[PATCH 16/20] secretmem: Convert to migrate_folio

[Matthew Wilcox (Oracle)]

This is little more than changing the types over; there's no real work
being done in this function.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/secretmem.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/secretmem.c b/mm/secretmem.c
index 206ed6b40c1d..9c7f6e3bf3e1 100644
--- a/mm/secretmem.c
+++ b/mm/secretmem.c
@@ -138,8 +138,8 @@ static bool secretmem_isolate_page(struct page *page, isolate_mode_t mode)
 	return false;
 }
 
-static int secretmem_migratepage(struct address_space *mapping,
-				 struct page *newpage, struct page *page,
+static int secretmem_migrate_folio(struct address_space *mapping,
+				 struct folio *dst, struct folio *src,
 				 enum migrate_mode mode)
 {
 	return -EBUSY;
@@ -154,7 +154,7 @@ static void secretmem_free_folio(struct folio *folio)
 const struct address_space_operations secretmem_aops = {
 	.dirty_folio	= noop_dirty_folio,
 	.free_folio	= secretmem_free_folio,
-	.migratepage	= secretmem_migratepage,
+	.migrate_folio	= secretmem_migrate_folio,
 	.isolate_page	= secretmem_isolate_page,
 };
 
-- 
2.35.1


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[PATCH 17/20] z3fold: Convert to migrate_folio

[Matthew Wilcox (Oracle)]

z3fold doesn't really use folios, but it needs to be called like this
in order to migrate an individual page.  Convert from a folio back to
a page until we decide how to handle migration better for z3fold.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/z3fold.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/mm/z3fold.c b/mm/z3fold.c
index f41f8b0d9e9a..5d091c41fb35 100644
--- a/mm/z3fold.c
+++ b/mm/z3fold.c
@@ -1554,9 +1554,11 @@ static bool z3fold_page_isolate(struct page *page, isolate_mode_t mode)
 	return false;
 }
 
-static int z3fold_page_migrate(struct address_space *mapping, struct page *newpage,
-			       struct page *page, enum migrate_mode mode)
+static int z3fold_migrate_folio(struct address_space *mapping,
+		struct folio *dst, struct folio *src, enum migrate_mode mode)
 {
+	struct page *newpage = &dst->page;
+	struct page *page = &src->page;
 	struct z3fold_header *zhdr, *new_zhdr;
 	struct z3fold_pool *pool;
 	struct address_space *new_mapping;
@@ -1644,7 +1646,7 @@ static void z3fold_page_putback(struct page *page)
 
 static const struct address_space_operations z3fold_aops = {
 	.isolate_page = z3fold_page_isolate,
-	.migratepage = z3fold_page_migrate,
+	.migrate_folio = z3fold_migrate_folio,
 	.putback_page = z3fold_page_putback,
 };
 
-- 
2.35.1


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[PATCH 18/20] zsmalloc: Convert to migrate_folio

[Matthew Wilcox (Oracle)]

zsmalloc doesn't really use folios, but it needs to be called like this
in order to migrate an individual page.  Convert from a folio back to
a page until we decide how to handle migration better for zsmalloc.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/zsmalloc.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 5d5fc04385b8..8ed79121195a 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -1865,9 +1865,11 @@ static bool zs_page_isolate(struct page *page, isolate_mode_t mode)
 	return true;
 }
 
-static int zs_page_migrate(struct address_space *mapping, struct page *newpage,
-		struct page *page, enum migrate_mode mode)
+static int zs_migrate_folio(struct address_space *mapping,
+		struct folio *dst, struct folio *src, enum migrate_mode mode)
 {
+	struct page *newpage = &dst->page;
+	struct page *page = &src->page;
 	struct zs_pool *pool;
 	struct size_class *class;
 	struct zspage *zspage;
@@ -1966,7 +1968,7 @@ static void zs_page_putback(struct page *page)
 
 static const struct address_space_operations zsmalloc_aops = {
 	.isolate_page = zs_page_isolate,
-	.migratepage = zs_page_migrate,
+	.migrate_folio = zs_migrate_folio,
 	.putback_page = zs_page_putback,
 };
 
-- 
2.35.1


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[PATCH 19/20] fs: Remove aops->migratepage()

[Matthew Wilcox (Oracle)]

With all users converted to migrate_folio(), remove this operation.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 include/linux/fs.h |  2 --
 mm/compaction.c    |  5 ++---
 mm/migrate.c       | 10 +---------
 3 files changed, 3 insertions(+), 14 deletions(-)

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 5737c92ed286..95347cc035ae 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -367,8 +367,6 @@ struct address_space_operations {
 	 */
 	int (*migrate_folio)(struct address_space *, struct folio *dst,
 			struct folio *src, enum migrate_mode);
-	int (*migratepage) (struct address_space *,
-			struct page *, struct page *, enum migrate_mode);
 	bool (*isolate_page)(struct page *, isolate_mode_t);
 	void (*putback_page)(struct page *);
 	int (*launder_folio)(struct folio *);
diff --git a/mm/compaction.c b/mm/compaction.c
index db34b459e5d9..f0dc62159c0e 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1034,7 +1034,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 
 			/*
 			 * Only pages without mappings or that have a
-			 * ->migratepage callback are possible to migrate
+			 * ->migrate_folio callback are possible to migrate
 			 * without blocking. However, we can be racing with
 			 * truncation so it's necessary to lock the page
 			 * to stabilise the mapping as truncation holds
@@ -1046,8 +1046,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 
 			mapping = page_mapping(page);
 			migrate_dirty = !mapping ||
-					mapping->a_ops->migrate_folio ||
-					mapping->a_ops->migratepage;
+					mapping->a_ops->migrate_folio;
 			unlock_page(page);
 			if (!migrate_dirty)
 				goto isolate_fail_put;
diff --git a/mm/migrate.c b/mm/migrate.c
index a8edd226c72d..c5560430dce4 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -911,9 +911,6 @@ static int move_to_new_folio(struct folio *dst, struct folio *src,
 			 */
 			rc = mapping->a_ops->migrate_folio(mapping, dst, src,
 								mode);
-		else if (mapping->a_ops->migratepage)
-			rc = mapping->a_ops->migratepage(mapping, &dst->page,
-							&src->page, mode);
 		else
 			rc = fallback_migrate_folio(mapping, dst, src, mode);
 	} else {
@@ -928,12 +925,7 @@ static int move_to_new_folio(struct folio *dst, struct folio *src,
 			goto out;
 		}
 
-		if (mapping->a_ops->migrate_folio)
-			rc = mapping->a_ops->migrate_folio(mapping, dst, src,
-								mode);
-		else
-			rc = mapping->a_ops->migratepage(mapping, &dst->page,
-							&src->page, mode);
+		rc = mapping->a_ops->migrate_folio(mapping, dst, src, mode);
 		WARN_ON_ONCE(rc == MIGRATEPAGE_SUCCESS &&
 				!folio_test_isolated(src));
 	}
-- 
2.35.1


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Re: [PATCH 19/20] fs: Remove aops->migratepage()

[Christoph Hellwig]

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

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[PATCH 20/20] mm/folio-compat: Remove migration compatibility functions

[Matthew Wilcox (Oracle)]

migrate_page_move_mapping(), migrate_page_copy() and migrate_page_states()
are all now unused after converting all the filesystems from
aops->migratepage() to aops->migrate_folio().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 include/linux/migrate.h | 11 -----------
 mm/folio-compat.c       | 22 ----------------------
 mm/ksm.c                |  2 +-
 3 files changed, 1 insertion(+), 34 deletions(-)

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 088749471485..4670f3aec232 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -33,12 +33,8 @@ extern int migrate_pages(struct list_head *l, new_page_t new, free_page_t free,
 extern struct page *alloc_migration_target(struct page *page, unsigned long private);
 extern int isolate_movable_page(struct page *page, isolate_mode_t mode);
 
-extern void migrate_page_states(struct page *newpage, struct page *page);
-extern void migrate_page_copy(struct page *newpage, struct page *page);
 int migrate_huge_page_move_mapping(struct address_space *mapping,
 		struct folio *dst, struct folio *src);
-extern int migrate_page_move_mapping(struct address_space *mapping,
-		struct page *newpage, struct page *page, int extra_count);
 void migration_entry_wait_on_locked(swp_entry_t entry, pte_t *ptep,
 				spinlock_t *ptl);
 void folio_migrate_flags(struct folio *newfolio, struct folio *folio);
@@ -59,13 +55,6 @@ static inline struct page *alloc_migration_target(struct page *page,
 static inline int isolate_movable_page(struct page *page, isolate_mode_t mode)
 	{ return -EBUSY; }
 
-static inline void migrate_page_states(struct page *newpage, struct page *page)
-{
-}
-
-static inline void migrate_page_copy(struct page *newpage,
-				     struct page *page) {}
-
 static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
 				  struct folio *dst, struct folio *src)
 {
diff --git a/mm/folio-compat.c b/mm/folio-compat.c
index 20bc15b57d93..458618c7302c 100644
--- a/mm/folio-compat.c
+++ b/mm/folio-compat.c
@@ -51,28 +51,6 @@ void mark_page_accessed(struct page *page)
 }
 EXPORT_SYMBOL(mark_page_accessed);
 
-#ifdef CONFIG_MIGRATION
-int migrate_page_move_mapping(struct address_space *mapping,
-		struct page *newpage, struct page *page, int extra_count)
-{
-	return folio_migrate_mapping(mapping, page_folio(newpage),
-					page_folio(page), extra_count);
-}
-EXPORT_SYMBOL(migrate_page_move_mapping);
-
-void migrate_page_states(struct page *newpage, struct page *page)
-{
-	folio_migrate_flags(page_folio(newpage), page_folio(page));
-}
-EXPORT_SYMBOL(migrate_page_states);
-
-void migrate_page_copy(struct page *newpage, struct page *page)
-{
-	folio_migrate_copy(page_folio(newpage), page_folio(page));
-}
-EXPORT_SYMBOL(migrate_page_copy);
-#endif
-
 bool set_page_writeback(struct page *page)
 {
 	return folio_start_writeback(page_folio(page));
diff --git a/mm/ksm.c b/mm/ksm.c
index 54f78c9eecae..e8f8c1a2bb39 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -712,7 +712,7 @@ static struct page *get_ksm_page(struct stable_node *stable_node,
 	 * however, it might mean that the page is under page_ref_freeze().
 	 * The __remove_mapping() case is easy, again the node is now stale;
 	 * the same is in reuse_ksm_page() case; but if page is swapcache
-	 * in migrate_page_move_mapping(), it might still be our page,
+	 * in folio_migrate_mapping(), it might still be our page,
 	 * in which case it's essential to keep the node.
 	 */
 	while (!get_page_unless_zero(page)) {
-- 
2.35.1


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Re: [PATCH 20/20] mm/folio-compat: Remove migration compatibility functions

[Christoph Hellwig]

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

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