USB: quatech2: switch to generic TIOCMIWAIT implementation

Switch to the generic TIOCMIWAIT implementation.

This also fixes the issue with processes waiting for
modem-status-changes not being woken up at disconnect.
Signed-off-by: NJohan Hovold <jhovold@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/serial/quatech2.c

@@ -492,49 +492,6 @@ static int get_serial_info(struct usb_serial_port *port,
 	return 0;
 }
 
-static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
-{
-	struct qt2_port_private *priv = usb_get_serial_port_data(port);
-	struct async_icount prev, cur;
-	unsigned long flags;
-
-	spin_lock_irqsave(&priv->lock, flags);
-	prev = port->icount;
-	spin_unlock_irqrestore(&priv->lock, flags);
-
-	while (1) {
-		wait_event_interruptible(port->delta_msr_wait,
-					 (port->serial->disconnected ||
-					  (port->icount.rng != prev.rng) ||
-					  (port->icount.dsr != prev.dsr) ||
-					  (port->icount.dcd != prev.dcd) ||
-					  (port->icount.cts != prev.cts)));
-
-		if (signal_pending(current))
-			return -ERESTARTSYS;
-
-		if (port->serial->disconnected)
-			return -EIO;
-
-		spin_lock_irqsave(&priv->lock, flags);
-		cur = port->icount;
-		spin_unlock_irqrestore(&priv->lock, flags);
-
-		if ((prev.rng == cur.rng) &&
-		    (prev.dsr == cur.dsr) &&
-		    (prev.dcd == cur.dcd) &&
-		    (prev.cts == cur.cts))
-			return -EIO;
-
-		if ((arg & TIOCM_RNG && (prev.rng != cur.rng)) ||
-		    (arg & TIOCM_DSR && (prev.dsr != cur.dsr)) ||
-		    (arg & TIOCM_CD && (prev.dcd != cur.dcd)) ||
-		    (arg & TIOCM_CTS && (prev.cts != cur.cts)))
-			return 0;
-	}
-	return 0;
-}
-
 static int qt2_ioctl(struct tty_struct *tty,
 		     unsigned int cmd, unsigned long arg)
 {
@@ -544,10 +501,6 @@ static int qt2_ioctl(struct tty_struct *tty,
 	case TIOCGSERIAL:
 		return get_serial_info(port,
 				       (struct serial_struct __user *)arg);
-
-	case TIOCMIWAIT:
-		return wait_modem_info(port, arg);
-
 	default:
 		break;
 	}
@@ -942,7 +895,7 @@ static void qt2_update_msr(struct usb_serial_port *port, unsigned char *ch)
 		if (newMSR & UART_MSR_TERI)
 			port->icount.rng++;
 
-		wake_up_interruptible(&port->delta_msr_wait);
+		wake_up_interruptible(&port->port.delta_msr_wait);
 	}
 }
 
@@ -1072,6 +1025,7 @@ static struct usb_serial_driver qt2_device = {
 	.break_ctl           = qt2_break_ctl,
 	.tiocmget            = qt2_tiocmget,
 	.tiocmset            = qt2_tiocmset,
+	.tiocmiwait          = usb_serial_generic_tiocmiwait,
 	.get_icount	     = usb_serial_generic_get_icount,
 	.ioctl               = qt2_ioctl,
 	.set_termios         = qt2_set_termios,