function wOw_login_redirect( $redirect_to, $request, $user ) {

    //is there a user to check?
    if ( isset( $user->roles ) && is_array( $user->roles ) ) {

        // admin or editor and no forum request
        if ( in_array( 'administrator', $user->roles ) && strpos($request, 'forum') == false || in_array( 'editor', $user->roles ) && strpos($request, 'forum') == false  ) {
            // redirect to requested page (most likely login) if not forum
            return admin_url();
        // no specific user - login page - lead to same page as requested
        } elseif ( strpos($request, 'login') !== false ) {
            // redirect them to the default place
              return $request;
        // all othe requests lead to default url
        } else {
            return $redirect_to;
        }
    } else {
        return home_url();
    }
}

add_filter( 'login_redirect', 'wOw_login_redirect', 10, 3 );