cgroup_clear_directory() incorrectly invokes cgroup_rm_file() on each
cftset of the target subsystems, which only removes the first file of
each set. This leaves dangling files after subsystems are removed
from a cgroup root via remount.
Use cgroup_addrm_files() to remove all files of target subsystems.
tj: Move cgroup_addrm_files() prototype decl upwards next to other
global declarations. Commit message updated.
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>