usb_wwan: fix error case in close()

The device never needs to be resumed in close(). But the counters
must be balanced. As resumption can fail, but the counters must
be balanced, use the _no_resume() version which cannot fail.
Signed-off-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/usb/serial/usb_wwan.c

@@ -424,6 +424,7 @@ int usb_wwan_open(struct tty_struct *tty, struct usb_serial_port *port)
 	spin_lock_irq(&intfdata->susp_lock);
 	portdata->opened = 1;
 	spin_unlock_irq(&intfdata->susp_lock);
+	/* this balances a get in the generic USB serial code */
 	usb_autopm_put_interface(serial->interface);
 
 	return 0;
@@ -450,7 +451,8 @@ void usb_wwan_close(struct usb_serial_port *port)
 			usb_kill_urb(portdata->in_urbs[i]);
 		for (i = 0; i < N_OUT_URB; i++)
 			usb_kill_urb(portdata->out_urbs[i]);
-		usb_autopm_get_interface(serial->interface);
+		/* balancing - important as an error cannot be handled*/
+		usb_autopm_get_interface_no_resume(serial->interface);
 		serial->interface->needs_remote_wakeup = 0;
 	}
 }