diff options
| author | Tejun Heo <tj@kernel.org> | 2012-11-19 08:13:38 -0800 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2012-11-19 08:13:38 -0800 |
| commit | b1929db42f8a649d9a9e397119f628c27fd4021f (patch) | |
| tree | 04c0fa6f056395f8d17b5cd918403547be3f1425 /kernel | |
| parent | 4b8b47eb0001a89f271d671d959b235faa8f03e2 (diff) | |
cgroup: allow ->post_create() to fail
There could be cases where controllers want to do initialization
operations which may fail from ->post_create(). This patch makes
->post_create() return -errno to indicate failure and online_css()
relay such failures.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Glauber Costa <glommer@parallels.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/cgroup.c | 29 | ||||
| -rw-r--r-- | kernel/cgroup_freezer.c | 4 |
2 files changed, 22 insertions, 11 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 027b66e66698..c389f4258681 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -4041,14 +4041,18 @@ static void init_cgroup_css(struct cgroup_subsys_state *css, INIT_WORK(&css->dput_work, css_dput_fn); } -/* invoke ->post_create() on a new CSS and mark it online */ -static void online_css(struct cgroup_subsys *ss, struct cgroup *cgrp) +/* invoke ->post_create() on a new CSS and mark it online if successful */ +static int online_css(struct cgroup_subsys *ss, struct cgroup *cgrp) { + int ret = 0; + lockdep_assert_held(&cgroup_mutex); if (ss->post_create) - ss->post_create(cgrp); - cgrp->subsys[ss->subsys_id]->flags |= CSS_ONLINE; + ret = ss->post_create(cgrp); + if (!ret) + cgrp->subsys[ss->subsys_id]->flags |= CSS_ONLINE; + return ret; } /* if the CSS is online, invoke ->pre_destory() on it and mark it offline */ @@ -4174,12 +4178,15 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, list_add_tail_rcu(&cgrp->sibling, &cgrp->parent->children); root->number_of_cgroups++; - for_each_subsys(root, ss) { - /* each css holds a ref to the cgroup's dentry */ + /* each css holds a ref to the cgroup's dentry */ + for_each_subsys(root, ss) dget(dentry); - /* creation succeeded, notify subsystems */ - online_css(ss, cgrp); + /* creation succeeded, notify subsystems */ + for_each_subsys(root, ss) { + err = online_css(ss, cgrp); + if (err) + goto err_destroy; } err = cgroup_populate_dir(cgrp, true, root->subsys_mask); @@ -4393,7 +4400,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss) BUG_ON(!list_empty(&init_task.tasks)); ss->active = 1; - online_css(ss, dummytop); + BUG_ON(online_css(ss, dummytop)); mutex_unlock(&cgroup_mutex); @@ -4500,7 +4507,9 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss) write_unlock(&css_set_lock); ss->active = 1; - online_css(ss, dummytop); + ret = online_css(ss, dummytop); + if (ret) + goto err_unload; /* success! */ mutex_unlock(&cgroup_mutex); diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c index 670a4af7dc94..ee8bb671688c 100644 --- a/kernel/cgroup_freezer.c +++ b/kernel/cgroup_freezer.c @@ -112,7 +112,7 @@ static struct cgroup_subsys_state *freezer_create(struct cgroup *cgroup) * parent's freezing state while holding both parent's and our * freezer->lock. */ -static void freezer_post_create(struct cgroup *cgroup) +static int freezer_post_create(struct cgroup *cgroup) { struct freezer *freezer = cgroup_freezer(cgroup); struct freezer *parent = parent_freezer(freezer); @@ -136,6 +136,8 @@ static void freezer_post_create(struct cgroup *cgroup) spin_unlock(&freezer->lock); if (parent) spin_unlock_irq(&parent->lock); + + return 0; } /** |