USB: sierra: fix urb and memory leak on disconnect

commit 014333f7 upstream.

The delayed-write queue was never emptied on disconnect, something which
would lead to leaked urbs and transfer buffers if the device is
disconnected before being runtime resumed due to a write.

Fixes: e6929a90 ("USB: support for autosuspend in sierra while
online")
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: adjust context, indentation]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/usb/serial/sierra.c

@@ -802,6 +802,7 @@ static void sierra_close(struct usb_serial_port *port)
 	struct usb_serial *serial = port->serial;
 	struct sierra_port_private *portdata;
 	struct sierra_intf_private *intfdata = port->serial->private;
+	struct urb *urb;
 
 
 	dev_dbg(&port->dev, "%s\n", __func__);
@@ -826,6 +827,17 @@ static void sierra_close(struct usb_serial_port *port)
 		portdata->opened = 0;
 		spin_unlock_irq(&intfdata->susp_lock);
 
+		for (;;) {
+			urb = usb_get_from_anchor(&portdata->delayed);
+			if (!urb)
+				break;
+			kfree(urb->transfer_buffer);
+			usb_free_urb(urb);
+			usb_autopm_put_interface_async(serial->interface);
+			spin_lock(&portdata->lock);
+			portdata->outstanding_urbs--;
+			spin_unlock(&portdata->lock);
+		}
 
 		/* Stop reading urbs */
 		sierra_stop_rx_urbs(port);