diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 76fe0a1..65a7f37 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -19,6 +19,7 @@
 #include <linux/proc_fs.h>
 
 #include <linux/mtd/mtd.h>
+#include "internal.h"
 
 #include "mtdcore.h"
 
@@ -46,6 +47,20 @@
 {
 	int i;
 
+	if (!mtd->backing_dev_info) {
+		switch (mtd->type) {
+		case MTD_RAM:
+			mtd->backing_dev_info = &mtd_bdi_rw_mappable;
+			break;
+		case MTD_ROM:
+			mtd->backing_dev_info = &mtd_bdi_ro_mappable;
+			break;
+		default:
+			mtd->backing_dev_info = &mtd_bdi_unmappable;
+			break;
+		}
+	}
+
 	BUG_ON(mtd->writesize == 0);
 	mutex_lock(&mtd_table_mutex);