diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
index 0cdaf9f..3e3449e 100644
--- a/drivers/mtd/ubi/cdev.c
+++ b/drivers/mtd/ubi/cdev.c
@@ -437,7 +437,8 @@
 			break;
 		}
 
-		rsvd_bytes = vol->reserved_pebs * (ubi->leb_size-vol->data_pad);
+		rsvd_bytes = (long long)vol->reserved_pebs *
+					ubi->leb_size-vol->data_pad;
 		if (bytes < 0 || bytes > rsvd_bytes) {
 			err = -EINVAL;
 			break;