TTY: Add tty ioctl to figure device node of the system console.

This has been in the SuSE kernels for a very long time.

Signed-off-by: Werner Fink <werner@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index be5ab4a..d2333ab 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2618,6 +2618,11 @@
 		return put_user(tty->ldisc->ops->num, (int __user *)p);
 	case TIOCSETD:
 		return tiocsetd(tty, p);
+	case TIOCGDEV:
+	{
+		unsigned int ret = new_encode_dev(tty_devnum(real_tty));
+		return put_user(ret, (unsigned int __user *)p);
+	}
 	/*
 	 * Break handling
 	 */