From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753191Ab2KTOkn (ORCPT ); Tue, 20 Nov 2012 09:40:43 -0500 Received: from mail-pa0-f46.google.com ([209.85.220.46]:58766 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752364Ab2KTOkl (ORCPT ); Tue, 20 Nov 2012 09:40:41 -0500 Date: Tue, 20 Nov 2012 06:40:36 -0800 From: Tejun Heo To: Daniel Wagner Cc: serge.hallyn@canonical.com, ebiederm@xmission.com, nhorman@tuxdriver.com, tgraf@suug.ch, davem@davemloft.net, lizefan@huawei.com, cgroups@vger.kernel.org, containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH 7/7] netprio_cgroup: allow nesting and inherit config on cgroup creation Message-ID: <20121120144036.GP15971@htj.dyndns.org> References: <1353400211-5182-1-git-send-email-tj@kernel.org> <1353400211-5182-8-git-send-email-tj@kernel.org> <50AB45EA.2050507@monom.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <50AB45EA.2050507@monom.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Daniel. On Tue, Nov 20, 2012 at 09:57:14AM +0100, Daniel Wagner wrote: > >-static void cgrp_css_free(struct cgroup *cgrp) > >+static int cgrp_css_online(struct cgroup *cgrp) > > { > >- struct cgroup_netprio_state *cs = cgrp_netprio_state(cgrp); > >+ struct cgroup *parent = cgrp->parent; > > struct net_device *dev; > >+ int ret = 0; > >+ > >+ if (!parent) > >+ return 0; > > BTW, parent is always != NULL, because the root cgroup will be > attached to the dummytop cgroup. Hmmm? I'm confused. When ->css_online() is called for dummytop in cgroup_init_subsys(), its parent is NULL. What am I missing? Thanks. -- tejun