USB: mos7840: 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/mos7840.c

@@ -219,7 +219,6 @@ struct moschip_port {
 	char open;
 	char open_ports;
 	wait_queue_head_t wait_chase;	/* for handling sleeping while waiting for chase to finish */
-	int delta_msr_cond;
 	struct usb_serial_port *port;	/* loop back to the owner of this object */
 
 	/* Offsets */
@@ -413,8 +412,7 @@ static void mos7840_handle_new_msr(struct moschip_port *port, __u8 new_msr)
 		if (new_msr & MOS_MSR_DELTA_RI)
 			icount->rng++;
 
-		mos7840_port->delta_msr_cond = 1;
-		wake_up_interruptible(&port->port->delta_msr_wait);
+		wake_up_interruptible(&port->port->port.delta_msr_wait);
 	}
 }
 
@@ -2113,9 +2111,6 @@ static int mos7840_ioctl(struct tty_struct *tty,
 	struct usb_serial_port *port = tty->driver_data;
 	void __user *argp = (void __user *)arg;
 	struct moschip_port *mos7840_port;
-	unsigned long flags;
-	struct async_icount cnow;
-	struct async_icount cprev;
 
 	if (mos7840_port_paranoia_check(port, __func__))
 		return -1;
@@ -2141,46 +2136,6 @@ static int mos7840_ioctl(struct tty_struct *tty,
 	case TIOCSSERIAL:
 		dev_dbg(&port->dev, "%s TIOCSSERIAL\n", __func__);
 		break;
-
-	case TIOCMIWAIT:
-		dev_dbg(&port->dev, "%s  TIOCMIWAIT\n", __func__);
-		spin_lock_irqsave(&port->lock, flags);
-		cprev = port->icount;
-		spin_unlock_irqrestore(&port->lock, flags);
-		while (1) {
-			/* interruptible_sleep_on(&mos7840_port->delta_msr_wait); */
-			mos7840_port->delta_msr_cond = 0;
-			wait_event_interruptible(port->delta_msr_wait,
-						 (port->serial->disconnected ||
-						  mos7840_port->
-						  delta_msr_cond == 1));
-
-			/* see if a signal did it */
-			if (signal_pending(current))
-				return -ERESTARTSYS;
-
-			if (port->serial->disconnected)
-				return -EIO;
-
-			spin_lock_irqsave(&port->lock, flags);
-			cnow = port->icount;
-			spin_unlock_irqrestore(&port->lock, flags);
-
-			if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
-			    cnow.dcd == cprev.dcd && cnow.cts == cprev.cts)
-				return -EIO;	/* no change => error */
-
-			if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
-			    ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
-			    ((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) ||
-			    ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
-				return 0;
-			}
-			cprev = cnow;
-		}
-		/* NOTREACHED */
-		break;
-
 	default:
 		break;
 	}
@@ -2527,6 +2482,7 @@ static struct usb_serial_driver moschip7840_4port_device = {
 	.break_ctl = mos7840_break,
 	.tiocmget = mos7840_tiocmget,
 	.tiocmset = mos7840_tiocmset,
+	.tiocmiwait = usb_serial_generic_tiocmiwait,
 	.get_icount = usb_serial_generic_get_icount,
 	.port_probe = mos7840_port_probe,
 	.port_remove = mos7840_port_remove,