mm/migrate: Add filemap_migrate_folio()

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>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

2 files changed, 6 insertions, 6 deletions

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 87d4ea571240..cc9adbaddb59 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);