tty: Move tty_ldisc_kill()

BugLink: http://bugs.launchpad.net/bugs/1709126

In preparation for destroying the line discipline instance on hangup,
move tty_ldisc_kill() to eliminate needless forward declarations.
No functional change.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 6ffeb4b2)
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Acked-by: Marcelo Cerri <marcelo.cerri@canonical.com>
Acked-by: Benjamin M Romer <benjamin.romer@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/tty/tty_ldisc.c

@@ -595,6 +595,25 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)
 	return retval;
 }
 
+/**
+ *	tty_ldisc_kill	-	teardown ldisc
+ *	@tty: tty being released
+ *
+ *	Perform final close of the ldisc and reset tty->ldisc
+ */
+static void tty_ldisc_kill(struct tty_struct *tty)
+{
+	if (!tty->ldisc)
+		return;
+	/*
+	 * Now kill off the ldisc
+	 */
+	tty_ldisc_close(tty, tty->ldisc);
+	tty_ldisc_put(tty->ldisc);
+	/* Force an oops if we mess this up */
+	tty->ldisc = NULL;
+}
+
 /**
  *	tty_reset_termios	-	reset terminal state
  *	@tty: tty to reset
@@ -742,19 +761,6 @@ int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty)
 	return 0;
 }
 
-static void tty_ldisc_kill(struct tty_struct *tty)
-{
-	if (!tty->ldisc)
-		return;
-	/*
-	 * Now kill off the ldisc
-	 */
-	tty_ldisc_close(tty, tty->ldisc);
-	tty_ldisc_put(tty->ldisc);
-	/* Force an oops if we mess this up */
-	tty->ldisc = NULL;
-}
-
 /**
  *	tty_ldisc_release		-	release line discipline
  *	@tty: tty being shut down (or one end of pty pair)