tty: audit: Early-out pty master reads earlier

Reads from pty masters are not logged; early-out before taking
locks.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/tty_audit.c

@@ -276,16 +276,16 @@ void tty_audit_add_data(struct tty_struct *tty, const void *data,
 	if (unlikely(size == 0))
 		return;
 
+	if (tty->driver->type == TTY_DRIVER_TYPE_PTY
+	    && tty->driver->subtype == PTY_TYPE_MASTER)
+		return;
+
 	spin_lock_irqsave(&current->sighand->siglock, flags);
 	audit_log_tty_passwd = current->signal->audit_tty_log_passwd;
 	spin_unlock_irqrestore(&current->sighand->siglock, flags);
 	if (!audit_log_tty_passwd && icanon && !L_ECHO(tty))
 		return;
 
-	if (tty->driver->type == TTY_DRIVER_TYPE_PTY
-	    && tty->driver->subtype == PTY_TYPE_MASTER)
-		return;
-
 	buf = tty_audit_buf_get(tty, icanon);
 	if (!buf)
 		return;