n_tty: Factor packet mode status change for reuse

Factor the packet mode status change from n_tty_flush_buffer
for use by follow-on patch.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/n_tty.c

@@ -223,6 +223,18 @@ static void reset_buffer_flags(struct tty_struct *tty)
 	n_tty_set_room(tty);
 }
 
+static void n_tty_packet_mode_flush(struct tty_struct *tty)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&tty->ctrl_lock, flags);
+	if (tty->link->packet) {
+		tty->ctrl_status |= TIOCPKT_FLUSHREAD;
+		wake_up_interruptible(&tty->link->read_wait);
+	}
+	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+}
+
 /**
  *	n_tty_flush_buffer	-	clean input queue
  *	@tty:	terminal device
@@ -237,19 +249,11 @@ static void reset_buffer_flags(struct tty_struct *tty)
 
 static void n_tty_flush_buffer(struct tty_struct *tty)
 {
-	unsigned long flags;
 	/* clear everything and unthrottle the driver */
 	reset_buffer_flags(tty);
 
-	if (!tty->link)
-		return;
-
-	spin_lock_irqsave(&tty->ctrl_lock, flags);
-	if (tty->link->packet) {
-		tty->ctrl_status |= TIOCPKT_FLUSHREAD;
-		wake_up_interruptible(&tty->link->read_wait);
-	}
-	spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+	if (tty->link)
+		n_tty_packet_mode_flush(tty);
 }
 
 /**