cgroup: unexport functions

With module support gone, a lot of functions no longer need to be
exported.  Unexport them.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NLi Zefan <lizefan@huawei.com>

kernel/cgroup.c

@@ -242,7 +242,6 @@ bool cgroup_is_descendant(struct cgroup *cgrp, struct cgroup *ancestor)
 	}
 	return false;
 }
-EXPORT_SYMBOL_GPL(cgroup_is_descendant);
 
 static int cgroup_is_releasable(const struct cgroup *cgrp)
 {
@@ -1664,7 +1663,6 @@ struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset)
 		return tset->single.task;
 	}
 }
-EXPORT_SYMBOL_GPL(cgroup_taskset_first);
 
 /**
  * cgroup_taskset_next - iterate to the next task in taskset
@@ -1683,7 +1681,6 @@ struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset)
 	tc = flex_array_get(tset->tc_array, tset->idx++);
 	return tc->task;
 }
-EXPORT_SYMBOL_GPL(cgroup_taskset_next);
 
 /**
  * cgroup_task_migrate - move a task from one cgroup to another.
@@ -2365,7 +2362,6 @@ int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
 	mutex_unlock(&cgroup_tree_mutex);
 	return ret;
 }
-EXPORT_SYMBOL_GPL(cgroup_add_cftypes);
 
 /**
  * cgroup_task_count - count the number of tasks in a cgroup.
@@ -2439,7 +2435,6 @@ css_next_child(struct cgroup_subsys_state *pos_css,
 
 	return cgroup_css(next, parent_css->ss);
 }
-EXPORT_SYMBOL_GPL(css_next_child);
 
 /**
  * css_next_descendant_pre - find the next descendant for pre-order walk
@@ -2482,7 +2477,6 @@ css_next_descendant_pre(struct cgroup_subsys_state *pos,
 
 	return NULL;
 }
-EXPORT_SYMBOL_GPL(css_next_descendant_pre);
 
 /**
  * css_rightmost_descendant - return the rightmost descendant of a css
@@ -2514,7 +2508,6 @@ css_rightmost_descendant(struct cgroup_subsys_state *pos)
 
 	return last;
 }
-EXPORT_SYMBOL_GPL(css_rightmost_descendant);
 
 static struct cgroup_subsys_state *
 css_leftmost_descendant(struct cgroup_subsys_state *pos)
@@ -2568,7 +2561,6 @@ css_next_descendant_post(struct cgroup_subsys_state *pos,
 	/* no sibling left, visit parent */
 	return css_parent(pos);
 }
-EXPORT_SYMBOL_GPL(css_next_descendant_post);
 
 /**
  * css_advance_task_iter - advance a task itererator to the next css_set