USB: sierra: fix urb and memory leak on disconnect

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: e6929a9 ("USB: support for autosuspend in sierra while
online")

Cc: <stable@vger.kernel.org>	# v2.6.32
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: jhovold

drivers/usb/serial/sierra.c

@@ -759,6 +759,7 @@ 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;
 
 	portdata = usb_get_serial_port_data(port);
 
@@ -780,6 +781,18 @@ 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);
+	}
+
 	sierra_stop_rx_urbs(port);
 	for (i = 0; i < portdata->num_in_urbs; i++) {
 		sierra_release_urb(portdata->in_urbs[i]);