From: Tejun Heo <tj@kernel.org>
Date: Mon, 26 Aug 2013 22:40:56 +0000 (-0400)
Subject: cgroup: make cgroup_css() take cgroup_subsys * instead and allow NULL subsys
X-Git-Tag: v3.12-rc1~173^2~4
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ca8bdcaff0d77990fb69e0f946018c96a70851cc;p=pandora-kernel.git

cgroup: make cgroup_css() take cgroup_subsys * instead and allow NULL subsys

cgroup_css() is no longer used in hot paths.  Make it take struct
cgroup_subsys * and allow the users to specify NULL subsys to obtain
the dummy_css.  This removes open-coded NULL subsystem testing in a
couple users and generally simplifies the code.

After this patch, css_from_dir() also allows NULL @ss and returns the
matching dummy_css.  This behavior change doesn't affect its only user
- perf.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---

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