cgroup: mark "notify_on_release" and "release_agent" cgroup files insane

The empty cgroup notification mechanism currently implemented in
cgroup is tragically outdated.  Forking and execing userland process
stopped being a viable notification mechanism more than a decade ago.
We're gonna have a saner mechanism.  Let's make it clear that this
abomination is going away.

Mark "notify_on_release" and "release_agent" with CFTYPE_INSANE.

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 1e0f445..b3bb8a3 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4052,6 +4052,7 @@ static struct cftype files[] = {
        },
        {
                .name = "notify_on_release",
+               .flags = CFTYPE_INSANE,
                .read_u64 = cgroup_read_notify_on_release,
                .write_u64 = cgroup_write_notify_on_release,
        },
@@ -4073,7 +4074,7 @@ static struct cftype files[] = {
        },
        {
                .name = "release_agent",
-               .flags = CFTYPE_ONLY_ON_ROOT,
+               .flags = CFTYPE_INSANE | CFTYPE_ONLY_ON_ROOT,
                .read_seq_string = cgroup_release_agent_show,
                .write_string = cgroup_release_agent_write,
                .max_write_len = PATH_MAX,