cgroup: implement cgroup_get_e_css()
authorTejun Heo <tj@kernel.org>
Tue, 18 Nov 2014 07:49:52 +0000 (02:49 -0500)
committerTejun Heo <tj@kernel.org>
Tue, 18 Nov 2014 07:49:52 +0000 (02:49 -0500)
commiteeecbd1971517103e06f11750dd1a9a1dc37e4e6
treeace58390ca7f2e7f7530a8a8b23d9449a00ae3be
parent56c807ba4e91f0980567b6a69de239677879b17f
cgroup: implement cgroup_get_e_css()

Implement cgroup_get_e_css() which finds and gets the effective css
for the specified cgroup and subsystem combination.  This function
always returns a valid pinned css.  This will be used by cgroup
writeback support.

While at it, add comment to cgroup_e_css() to explain why that
function is different from cgroup_get_e_css() and has to test
cgrp->child_subsys_mask instead of cgroup_css(cgrp, ss).

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Zefan Li <lizefan@huawei.com>
include/linux/cgroup.h
kernel/cgroup.c