Merge branch 'for-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu

[karo-tx-linux.git] / include / linux / cgroup.h

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 549aed8de32b8f526e496c97b1f4c70b1ff392ae..bddebc5cf8e7501d779f3e59b3027d482b37e7d1 100644 (file)
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -473,6 +473,7 @@ struct cftype {
 };
 
 extern struct cgroup_root cgrp_dfl_root;
+extern struct css_set init_css_set;
 
 static inline bool cgroup_on_dfl(const struct cgroup *cgrp)
 {
@@ -700,6 +701,20 @@ static inline struct cgroup_subsys_state *task_css(struct task_struct *task,
        return task_css_check(task, subsys_id, false);
 }
 
+/**
+ * task_css_is_root - test whether a task belongs to the root css
+ * @task: the target task
+ * @subsys_id: the target subsystem ID
+ *
+ * Test whether @task belongs to the root css on the specified subsystem.
+ * May be invoked in any context.
+ */
+static inline bool task_css_is_root(struct task_struct *task, int subsys_id)
+{
+       return task_css_check(task, subsys_id, true) ==
+               init_css_set.subsys[subsys_id];
+}
+
 static inline struct cgroup *task_cgroup(struct task_struct *task,
                                         int subsys_id)
 {