fuse: convert iomap ops to ->iomap_next()

Convert fuse iomap_ops to the new ->iomap_next() callback. Each callback is
generated with the DEFINE_IOMAP_ITER_NEXT()/DEFINE_IOMAP_ITER_NEXT_END()
macros, which wrap the iomap_iter_next() helper to finish the previous
mapping if needed and produce the next one. No functional changes are
intended.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Link: https://patch.msgid.link/20260729192737.3190206-19-joannelkoong@gmail.com
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>

fs/fuse/dax.c

@@ -653,9 +653,11 @@ static int fuse_iomap_end(struct inode *inode, loff_t pos, loff_t length,
 	return 0;
 }
 
+static DEFINE_IOMAP_ITER_NEXT_END(fuse_iomap_next, fuse_iomap_begin,
+				  fuse_iomap_end);
+
 static const struct iomap_ops fuse_iomap_ops = {
-	.iomap_begin = fuse_iomap_begin,
-	.iomap_end = fuse_iomap_end,
+	.iomap_next = fuse_iomap_next,
 };
 
 static void fuse_wait_dax_page(struct inode *inode)

fs/fuse/file.c

@@ -890,8 +890,10 @@ static int fuse_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
 	return 0;
 }
 
+static DEFINE_IOMAP_ITER_NEXT(fuse_iomap_next, fuse_iomap_begin);
+
 static const struct iomap_ops fuse_iomap_ops = {
-	.iomap_begin	= fuse_iomap_begin,
+	.iomap_next	= fuse_iomap_next,
 };
 
 struct fuse_fill_read_data {

fs/fuse/virtio_fs.c

@@ -1024,8 +1024,7 @@ static void virtio_fs_cleanup_vqs(struct virtio_device *vdev)
 }
 
 /* Map a window offset to a page frame number.  The window offset will have
- * been produced by .iomap_begin(), which maps a file offset to a window
- * offset.
+ * been produced by .iomap_next(), which maps a file offset to a window offset.
  */
 static long virtio_fs_direct_access(struct dax_device *dax_dev, pgoff_t pgoff,
 				    long nr_pages, enum dax_access_mode mode,