// Redirect users to previous page upon login
if ( (isset($_GET['action']) && $_GET['action'] != 'logout') || (isset($_POST['login_location']) && !empty($_POST['login_location'])) ) {
        add_filter('login_redirect', 'my_login_redirect', 10, 3);
        function my_login_redirect() {
                $location = $_SERVER['HTTP_REFERER'];
                wp_safe_redirect($location);
                exit();
        }
}