From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752738AbaBNI4Z (ORCPT ); Fri, 14 Feb 2014 03:56:25 -0500 Received: from szxga03-in.huawei.com ([119.145.14.66]:55035 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752708AbaBNI4U (ORCPT ); Fri, 14 Feb 2014 03:56:20 -0500 Message-ID: <52FDDA24.6080204@huawei.com> Date: Fri, 14 Feb 2014 16:56:04 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 MIME-Version: 1.0 To: Tejun Heo CC: LKML , Cgroups Subject: [PATCH 3/3] cgroup: deal with dummp_top in cgroup_name() and cgroup_path() References: <52FDD9C4.1070001@huawei.com> In-Reply-To: <52FDD9C4.1070001@huawei.com> Content-Type: text/plain; charset="GB2312" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.18.230] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org My kernel fails to boot, because blkcg calls cgroup_path() while cgroupfs is not mounted. Fix both cgroup_name() and cgroup_path(). Signed-off-by: Li Zefan --- include/linux/cgroup.h | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index ef0b3af..8c283a9 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -487,13 +487,21 @@ struct cgroup_subsys_state *seq_css(struct seq_file *seq); static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen) { - return kernfs_name(cgrp->kn, buf, buflen); + /* dummy_top doesn't have a kn associated */ + if (cgrp->kn) + return kernfs_name(cgrp->kn, buf, buflen); + else + return strlcpy(buf, "/", buflen); } static inline char * __must_check cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen) { - return kernfs_path(cgrp->kn, buf, buflen); + /* dummy_top doesn't have a kn associated */ + if (cgrp->kn) + return kernfs_path(cgrp->kn, buf, buflen); + strlcpy(buf, "/", buflen); + return (buflen <= 2) ? NULL : buf; } static inline void pr_cont_cgroup_name(struct cgroup *cgrp) -- 1.8.0.2