From: Tejun Heo <tj@kernel.org>
Date: Tue, 18 Nov 2014 07:49:50 +0000 (-0500)
Subject: cgroup: restructure child_subsys_mask handling in cgroup_subtree_control_write()
X-Git-Tag: omap-for-v3.20/drop-legacy-3517~114^2~4
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=755bf5ee8633b97d8fd0ffbb4221662056dda22b;p=pandora-kernel.git

cgroup: restructure child_subsys_mask handling in cgroup_subtree_control_write()

Make cgroup_subtree_control_write() first calculate new
subtree_control (new_sc), child_subsys_mask (new_ss) and
css_enable/disable masks before applying them to the cgroup.  Also,
store the original subtree_control (old_sc) and child_subsys_mask
(old_ss) and use them to restore the orignal state after failure.

This patch shouldn't cause any behavior changes.  This prepares for a
fix for a bug in the async css offline wait logic.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Zefan Li <lizefan@huawei.com>
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