Merge remote-tracking branch 'cgroup/for-next'

[deliverable/linux.git] / include / linux / cgroup.h

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 984f73b719a99b10a6e683cff5a55d4a41b57527..c4688742ddc402030df5049a1051fae5f00aa8c3 100644 (file)
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -97,7 +97,7 @@ int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
 int cgroup_rm_cftypes(struct cftype *cfts);
 void cgroup_file_notify(struct cgroup_file *cfile);
 
-char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen);
+int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen);
 int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry);
 int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
                     struct pid *pid, struct task_struct *tsk);
@@ -497,6 +497,23 @@ static inline bool cgroup_is_descendant(struct cgroup *cgrp,
        return cgrp->ancestor_ids[ancestor->level] == ancestor->id;
 }
 
+/**
+ * task_under_cgroup_hierarchy - test task's membership of cgroup ancestry
+ * @task: the task to be tested
+ * @ancestor: possible ancestor of @task's cgroup
+ *
+ * Tests whether @task's default cgroup hierarchy is a descendant of @ancestor.
+ * It follows all the same rules as cgroup_is_descendant, and only applies
+ * to the default hierarchy.
+ */
+static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
+                                              struct cgroup *ancestor)
+{
+       struct css_set *cset = task_css_set(task);
+
+       return cgroup_is_descendant(cset->dfl_cgrp, ancestor);
+}
+
 /* no synchronization, the result can only be used as a hint */
 static inline bool cgroup_is_populated(struct cgroup *cgrp)
 {
@@ -538,8 +555,7 @@ static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen)
        return kernfs_name(cgrp->kn, buf, buflen);
 }
 
-static inline char * __must_check cgroup_path(struct cgroup *cgrp, char *buf,
-                                             size_t buflen)
+static inline int cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen)
 {
        return kernfs_path(cgrp->kn, buf, buflen);
 }
@@ -557,6 +573,7 @@ static inline void pr_cont_cgroup_path(struct cgroup *cgrp)
 #else /* !CONFIG_CGROUPS */
 
 struct cgroup_subsys_state;
+struct cgroup;
 
 static inline void css_put(struct cgroup_subsys_state *css) {}
 static inline int cgroup_attach_task_all(struct task_struct *from,
@@ -574,6 +591,11 @@ static inline void cgroup_free(struct task_struct *p) {}
 static inline int cgroup_init_early(void) { return 0; }
 static inline int cgroup_init(void) { return 0; }
 
+static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
+                                              struct cgroup *ancestor)
+{
+       return true;
+}
 #endif /* !CONFIG_CGROUPS */
 
 /*
@@ -634,8 +656,8 @@ struct cgroup_namespace *copy_cgroup_ns(unsigned long flags,
                                        struct user_namespace *user_ns,
                                        struct cgroup_namespace *old_ns);
 
-char *cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
-                    struct cgroup_namespace *ns);
+int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
+                  struct cgroup_namespace *ns);
 
 #else /* !CONFIG_CGROUPS */