tree fd9e909ad92609eb189d406c4812325788d25bbc
parent 42809dd4225b2f3127a4804314a1b33608620d96
author Tejun Heo <tj@kernel.org> 1353341617 -0800
committer Tejun Heo <tj@kernel.org> 1353341617 -0800

cgroup: introduce CSS_ONLINE flag and on/offline_css() helpers

New helpers on/offline_css() respectively wrap ->post_create() and
->pre_destroy() invocations.  online_css() sets CSS_ONLINE after
->post_create() is complete and offline_css() invokes ->pre_destroy()
iff CSS_ONLINE is set and clears it while also handling the temporary
dropping of cgroup_mutex.

This patch doesn't introduce any behavior change at the moment but
will be used to improve cgroup_create() failure path and allow
->post_create() to fail.

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