tty_port: Move hupcl handling

Move the HUCPL handling from the end of close_port_start to the beginning
of close_port_end. What this actually does is change the ordering from

	port shutdown
	port->dtr_rts

to

	port->dtr_rts
	port shutdown

Some hardware drops the physical connection on shutdown so we must perform
the port operations before the shutdown.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/char/tty_port.c

@@ -339,6 +339,14 @@ int tty_port_close_start(struct tty_port *port,
 			timeout = 2 * HZ;
 		schedule_timeout_interruptible(timeout);
 	}
+	/* Flush the ldisc buffering */
+	tty_ldisc_flush(tty);
+
+	/* Drop DTR/RTS if HUPCL is set. This causes any attached modem to
+	   hang up the line */
+	if (tty->termios->c_cflag & HUPCL)
+		tty_port_lower_dtr_rts(port);
+
 	/* Don't call port->drop for the last reference. Callers will want
 	   to drop the last active reference in ->shutdown() or the tty
 	   shutdown path */
@@ -350,11 +358,6 @@ void tty_port_close_end(struct tty_port *port, struct tty_struct *tty)
 {
 	unsigned long flags;
 
-	tty_ldisc_flush(tty);
-
-	if (tty->termios->c_cflag & HUPCL)
-		tty_port_lower_dtr_rts(port);
-
 	spin_lock_irqsave(&port->lock, flags);
 	tty->closing = 0;