diff --git a/drivers/staging/ozwpan/ozusbsvc1.c b/drivers/staging/ozwpan/ozusbsvc1.c
index 7b13dc9101721a..f660bb198c6553 100644
--- a/drivers/staging/ozwpan/ozusbsvc1.c
+++ b/drivers/staging/ozwpan/ozusbsvc1.c
@@ -326,10 +326,11 @@ static void oz_usb_handle_ep_data(struct oz_usb_ctx *usb_ctx,
 			struct oz_multiple_fixed *body =
 				(struct oz_multiple_fixed *)data_hdr;
 			u8 *data = body->data;
-			int n;
-			if (!body->unit_size)
+			unsigned int n;
+			if (!body->unit_size ||
+				len < sizeof(struct oz_multiple_fixed) - 1)
 				break;
-			n = (len - sizeof(struct oz_multiple_fixed)+1)
+			n = (len - (sizeof(struct oz_multiple_fixed) - 1))
 				/ body->unit_size;
 			while (n--) {
 				oz_hcd_data_ind(usb_ctx->hport, body->endpoint,