nfs: Convert to migrate_folio

Use a folio throughout this function.  migrate_page() will be converted
later.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

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,

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

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