v4.19.13 snapshot.
diff --git a/drivers/md/md-linear.h b/drivers/md/md-linear.h
new file mode 100644
index 0000000..8381d65
--- /dev/null
+++ b/drivers/md/md-linear.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINEAR_H
+#define _LINEAR_H
+
+struct dev_info {
+	struct md_rdev	*rdev;
+	sector_t	end_sector;
+};
+
+struct linear_conf
+{
+	struct rcu_head		rcu;
+	sector_t		array_sectors;
+	int			raid_disks; /* a copy of mddev->raid_disks */
+	struct dev_info		disks[0];
+};
+#endif