device_cgroup: use css_has_online_children() instead of has_children()
devcgroup_update_access() wants to know whether there are child
cgroups which are online and visible to userland and has_children()
may return false positive. Replace it with css_has_online_children().
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Aristeu Rozanski <aris@redhat.com>
Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Li Zefan <lizefan@huawei.com>
diff --git a/security/device_cgroup.c b/security/device_cgroup.c
index 084c8e4..d9d69e6 100644
--- a/security/device_cgroup.c
+++ b/security/device_cgroup.c
@@ -587,21 +587,6 @@
return rc;
}
-static inline bool has_children(struct dev_cgroup *devcgroup)
-{
- bool ret;
-
- /*
- * FIXME: There may be lingering offline csses and this function
- * may return %true when there isn't any userland-visible child
- * which is incorrect for our purposes.
- */
- rcu_read_lock();
- ret = css_next_child(NULL, &devcgroup->css);
- rcu_read_unlock();
- return ret;
-}
-
/*
* Modify the exception list using allow/deny rules.
* CAP_SYS_ADMIN is needed for this. It's at least separate from CAP_MKNOD
@@ -634,7 +619,7 @@
case 'a':
switch (filetype) {
case DEVCG_ALLOW:
- if (has_children(devcgroup))
+ if (css_has_online_children(&devcgroup->css))
return -EINVAL;
if (!may_allow_all(parent))
@@ -650,7 +635,7 @@
return rc;
break;
case DEVCG_DENY:
- if (has_children(devcgroup))
+ if (css_has_online_children(&devcgroup->css))
return -EINVAL;
dev_exception_clean(devcgroup);