From 33a68ac1c1b695216e873ee12e819adbe73e4d9f Mon Sep 17 00:00:00 2001
From: Li Zefan <lizf@cn.fujitsu.com>
Date: Wed, 7 Jan 2009 18:07:42 -0800
Subject: [PATCH] cgroups: add inactive subsystems to rootnode.subsys_list
Though for an inactive hierarchy, we have subsys->root == &rootnode, but
rootnode's subsys_list is always empty.
This conflicts with the code in find_css_set():
for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
...
if (ss->root->subsys_list.next == &ss->sibling) {
...
}
}
if (list_empty(&rootnode.subsys_list)) {
...
}
The above code assumes rootnode.subsys_list links all inactive
hierarchies.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
kernel/cgroup.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index fd572d057691..abf7248f501a 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -712,7 +712,7 @@ static int rebind_subsystems(struct cgroupfs_root *root,
BUG_ON(dummytop->subsys[i]->cgroup != dummytop);
cgrp->subsys[i] = dummytop->subsys[i];
cgrp->subsys[i]->cgroup = cgrp;
- list_add(&ss->sibling, &root->subsys_list);
+ list_move(&ss->sibling, &root->subsys_list);
ss->root = root;
if (ss->bind)
ss->bind(ss, cgrp);
@@ -726,7 +726,7 @@ static int rebind_subsystems(struct cgroupfs_root *root,
dummytop->subsys[i]->cgroup = dummytop;
cgrp->subsys[i] = NULL;
subsys[i]->root = &rootnode;
- list_del(&ss->sibling);
+ list_move(&ss->sibling, &rootnode.subsys_list);
} else if (bit & final_bits) {
/* Subsystem state should already exist */
BUG_ON(!cgrp->subsys[i]);
@@ -2521,6 +2521,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss)
printk(KERN_INFO "Initializing cgroup subsys %s\n", ss->name);
/* Create the top cgroup state for this subsystem */
+ list_add(&ss->sibling, &rootnode.subsys_list);
ss->root = &rootnode;
css = ss->create(ss, dummytop);
/* We don't handle early failures gracefully */