From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx134.postini.com [74.125.245.134]) by kanga.kvack.org (Postfix) with SMTP id 81F386B0031 for ; Wed, 24 Jul 2013 10:10:47 -0400 (EDT) Date: Wed, 24 Jul 2013 16:10:45 +0200 From: Michal Hocko Subject: Re: [PATCH v2 3/8] cgroup: implement cgroup_from_id() Message-ID: <20130724141045.GF2540@dhcp22.suse.cz> References: <51EFA554.6080801@huawei.com> <51EFA5C7.40504@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51EFA5C7.40504@huawei.com> Sender: owner-linux-mm@kvack.org List-ID: To: Li Zefan Cc: Tejun Heo , Andrew Morton , Glauber Costa , KAMEZAWA Hiroyuki , Johannes Weiner , LKML , Cgroups , linux-mm@kvack.org On Wed 24-07-13 18:00:39, Li Zefan wrote: > This will be used as a replacement for css_lookup(). > > There's a difference with cgroup id and css id. cgroup id starts with 0, > while css id starts with 1. > > Signed-off-by: Li Zefan Reviewed-by: Michal Hocko Typo fix bellow [...] > diff --git a/kernel/cgroup.c b/kernel/cgroup.c > index ee3c02e..9b27775 100644 > --- a/kernel/cgroup.c > +++ b/kernel/cgroup.c > @@ -5536,6 +5536,22 @@ struct cgroup_subsys_state *cgroup_css_from_dir(struct file *f, int id) > return css ? css : ERR_PTR(-ENOENT); > } > > +/** > + * cgroup_from_id - lookup cgroup by id > + * @ss: cgroup subsys to be looked into > + * @id: the cgroup id > + * > + * Returns the cgroup is there's valid one with @id, otherwise returns Null. s/ is / if / > + * Should be called under rcu_readlock(). > + */ > +struct cgroup *cgroup_from_id(struct cgroup_subsys *ss, int id) > +{ > + rcu_lockdep_assert(rcu_read_lock_held(), > + "cgroup_from_id() needs rcu_read_lock()" > + " protection"); > + return idr_find(&ss->root->cgroup_idr, id); > +} > + > #ifdef CONFIG_CGROUP_DEBUG > static struct cgroup_subsys_state *debug_css_alloc(struct cgroup *cgrp) > { > -- > 1.8.0.2 -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org