+ priv = usb_get_serial_port_data(port);
+ if (!priv) {
+ dbg("%s - bad port private data pointer - exiting", __FUNCTION__);
+ return;
+ }
+ /* account for transferred data */
+ countback = urb->actual_length;
+ data_offset = priv->write_offset;
+ if (data_offset > 0) {
+ /* Subtract the control bytes */
+ countback -= (data_offset * ((countback + (PKTSZ - 1)) / PKTSZ));
+ }
+ spin_lock_irqsave(&priv->tx_lock, flags);
+ --priv->tx_outstanding_urbs;
+ priv->tx_outstanding_bytes -= countback;
+ spin_unlock_irqrestore(&priv->tx_lock, flags);
+