cgroup: cgroup_apply_cftypes() shouldn't skip the default hierarhcy

cgroup_apply_cftypes() skip creating or removing files if the
subsystem is attached to the default hierarchy, which led to missing
files in the root of the default hierarchy.

Skipping made sense when the default hierarchy was dummy; however, now
that the default hierarchy is full functional and planned to be used
as the unified hierarchy, it shouldn't be skipped over.

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

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 11a03d67635a79fd18242e85b114fefaea980efe..a6894272353b29a503b7b2a4d5b28d3bf4407e51 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2436,10 +2436,6 @@ static int cgroup_apply_cftypes(struct cftype *cfts, bool is_add)
 
        lockdep_assert_held(&cgroup_tree_mutex);
 
-       /* don't bother if @ss isn't attached */
-       if (ss->root == &cgrp_dfl_root)
-               return 0;
-
        /* add/rm files for all cgroups created before */
        css_for_each_descendant_pre(css, cgroup_css(root, ss)) {
                struct cgroup *cgrp = css->cgroup;