diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index fab23ee..20104443 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -849,9 +849,10 @@
 {
 	int i;
 	struct acm_wb *wb;
+	struct usb_device *usb_dev = interface_to_usbdev(acm->control);
 
 	for (wb = &acm->wb[0], i = 0; i < ACM_NW; i++, wb++) {
-		usb_buffer_free(acm->dev, acm->writesize, wb->buf, wb->dmah);
+		usb_buffer_free(usb_dev, acm->writesize, wb->buf, wb->dmah);
 	}
 }