diff options
Diffstat (limited to 'include/linux/cgroup.h')
| -rw-r--r-- | include/linux/cgroup.h | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 5db8138a0482..b0d5f53ae5e1 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -225,6 +225,9 @@ struct cgroup { struct list_head pidlists; struct mutex pidlist_mutex; + /* dummy css with NULL ->ss, points back to this cgroup */ + struct cgroup_subsys_state dummy_css; + /* For css percpu_ref killing and RCU-protected deletion */ struct rcu_head rcu_head; struct work_struct destroy_work; @@ -668,7 +671,13 @@ struct cgroup_subsys_state *css_parent(struct cgroup_subsys_state *css) { struct cgroup *parent_cgrp = css->cgroup->parent; - return parent_cgrp ? parent_cgrp->subsys[css->ss->subsys_id] : NULL; + if (!parent_cgrp) + return NULL; + + if (css->ss) + return parent_cgrp->subsys[css->ss->subsys_id]; + else + return &parent_cgrp->dummy_css; } /** |