diff options
| -rw-r--r-- | include/linux/cgroup.h | 15 | ||||
| -rw-r--r-- | kernel/cgroup.c | 2 |
2 files changed, 16 insertions, 1 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index c2515851c1aa..d60904b9e505 100644 --- 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) { diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 11a03d67635a..3f1ca934a237 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -348,7 +348,7 @@ struct cgrp_cset_link { * reference-counted, to improve performance when child cgroups * haven't been created. */ -static struct css_set init_css_set = { +struct css_set init_css_set = { .refcount = ATOMIC_INIT(1), .cgrp_links = LIST_HEAD_INIT(init_css_set.cgrp_links), .tasks = LIST_HEAD_INIT(init_css_set.tasks), |