From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753678AbaJMVYZ (ORCPT ); Mon, 13 Oct 2014 17:24:25 -0400 Received: from mail-ig0-f202.google.com ([209.85.213.202]:53643 "EHLO mail-ig0-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753276AbaJMVYS (ORCPT ); Mon, 13 Oct 2014 17:24:18 -0400 From: Aditya Kali To: tj@kernel.org, lizefan@huawei.com, serge.hallyn@ubuntu.com, luto@amacapital.net, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, mingo@redhat.com Cc: containers@lists.linux-foundation.org, jnagal@google.com, Aditya Kali Subject: [PATCHv1 3/8] cgroup: add function to get task's cgroup on default hierarchy Date: Mon, 13 Oct 2014 14:23:45 -0700 Message-Id: <1413235430-22944-4-git-send-email-adityakali@google.com> X-Mailer: git-send-email 2.1.0.rc2.206.gedb03e5 In-Reply-To: <1413235430-22944-1-git-send-email-adityakali@google.com> References: <1413235430-22944-1-git-send-email-adityakali@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org get_task_cgroup() returns the (reference counted) cgroup of the given task on the default hierarchy. Signed-off-by: Aditya Kali --- include/linux/cgroup.h | 1 + kernel/cgroup.c | 25 +++++++++++++++++++++++++ 2 files changed, 26 insertions(+) diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 1d51968..80ed6e0 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -579,6 +579,7 @@ static inline void pr_cont_cgroup_path(struct cgroup *cgrp) } char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen); +struct cgroup *get_task_cgroup(struct task_struct *task); int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); diff --git a/kernel/cgroup.c b/kernel/cgroup.c index cab7dc4..56d507b 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1916,6 +1916,31 @@ char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen) } EXPORT_SYMBOL_GPL(task_cgroup_path); +/* + * get_task_cgroup - returns the cgroup of the task in the default cgroup + * hierarchy. + * + * @task: target task + * This function returns the @task's cgroup on the default cgroup hierarchy. The + * returned cgroup has its reference incremented (by calling cgroup_get()). So + * the caller must cgroup_put() the obtained reference once it is done with it. + */ +struct cgroup *get_task_cgroup(struct task_struct *task) +{ + struct cgroup *cgrp; + + mutex_lock(&cgroup_mutex); + down_read(&css_set_rwsem); + + cgrp = task_cgroup_from_root(task, &cgrp_dfl_root); + cgroup_get(cgrp); + + up_read(&css_set_rwsem); + mutex_unlock(&cgroup_mutex); + return cgrp; +} +EXPORT_SYMBOL_GPL(get_task_cgroup); + /* used to track tasks and other necessary states during migration */ struct cgroup_taskset { /* the src and dst cset list running through cset->mg_node */ -- 2.1.0.rc2.206.gedb03e5