cgroup: hold cgroup_mutex before calling css_offline()
cpuset no longer nests cgroup_mutex inside cpu_hotplug lock, so
we don't have to release cgroup_mutex before calling css_offline().
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index fd0b056..49297cb 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4169,17 +4169,8 @@
if (!(css->flags & CSS_ONLINE))
return;
- /*
- * css_offline() should be called with cgroup_mutex unlocked. See
- * 3fa59dfbc3 ("cgroup: fix potential deadlock in pre_destroy") for
- * details. This temporary unlocking should go away once
- * cgroup_mutex is unexported from controllers.
- */
- if (ss->css_offline) {
- mutex_unlock(&cgroup_mutex);
+ if (ss->css_offline)
ss->css_offline(cgrp);
- mutex_lock(&cgroup_mutex);
- }
cgrp->subsys[ss->subsys_id]->flags &= ~CSS_ONLINE;
}
