cgroup: unexport locking interface and cgroup_attach_task()

Now that all external cgroup_lock() users are gone, we can finally
unexport the locking interface and prevent future abuse of
cgroup_mutex.

Make cgroup_[un]lock() and cgroup_lock_live_group() static.  Also,
cgroup_attach_task() doesn't have any user left and can't be used
without locking interface anyway.  Make it static too.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>

1 files changed, 0 insertions, 5 deletions

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index f8eb01d75ddc..63deb70f3149 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -30,10 +30,7 @@ struct css_id;
 
 extern int cgroup_init_early(void);
 extern int cgroup_init(void);
-extern void cgroup_lock(void);
 extern int cgroup_lock_is_held(void);
-extern bool cgroup_lock_live_group(struct cgroup *cgrp);
-extern void cgroup_unlock(void);
 extern void cgroup_fork(struct task_struct *p);
 extern void cgroup_post_fork(struct task_struct *p);
 extern void cgroup_exit(struct task_struct *p, int run_callbacks);
@@ -693,8 +690,6 @@ struct task_struct *cgroup_iter_next(struct cgroup *cgrp,
                                         struct cgroup_iter *it);
 void cgroup_iter_end(struct cgroup *cgrp, struct cgroup_iter *it);
 int cgroup_scan_tasks(struct cgroup_scanner *scan);
-int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk,
-                       bool threadgroup);
 int cgroup_attach_task_all(struct task_struct *from, struct task_struct *);
 int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from);