diff options
| author | Tejun Heo <tj@kernel.org> | 2012-11-19 08:13:37 -0800 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2012-11-19 08:13:37 -0800 |
| commit | d19e19de48aa0b90c56cd93c8a46ebac46273429 (patch) | |
| tree | ea485692e0b5a7fdfa6bf6a80558957e89b220c2 /kernel | |
| parent | a31f2d3ff7fe20cbe2a143515a7d7c408b29dd0d (diff) | |
cgroup: simplify cgroup_load_subsys() failure path
Now that cgroup_unload_subsys() can tell whether the root css is
online or not, we can safely call cgroup_unload_subsys() after idr
init failure in cgroup_load_subsys().
Replace the manual unrolling and invoke cgroup_unload_subsys() on
failure. This drops cgroup_mutex inbetween but should be safe as the
subsystem will fail try_module_get() and thus can't be mounted
inbetween. As this means that cgroup_unload_subsys() can be called
before css_sets are rehashed, remove BUG_ON() on %NULL
css_set->subsys[] from cgroup_unload_subsys().
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/cgroup.c | 21 |
1 files changed, 10 insertions, 11 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 78a3d5c0968e..166b5141f3d4 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -4400,8 +4400,8 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss) */ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss) { - int i; struct cgroup_subsys_state *css; + int i, ret; /* check name and function validity */ if (ss->name == NULL || strlen(ss->name) > MAX_CGROUP_TYPE_NAMELEN || @@ -4452,15 +4452,9 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss) init_cgroup_css(css, ss, dummytop); /* init_idr must be after init_cgroup_css because it sets css->id. */ if (ss->use_id) { - int ret = cgroup_init_idr(ss, css); - if (ret) { - ss->destroy(dummytop); - dummytop->subsys[ss->subsys_id] = NULL; - subsys[ss->subsys_id] = NULL; - list_del_init(&ss->sibling); - mutex_unlock(&cgroup_mutex); - return ret; - } + ret = cgroup_init_idr(ss, css); + if (ret) + goto err_unload; } /* @@ -4498,6 +4492,12 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss) /* success! */ mutex_unlock(&cgroup_mutex); return 0; + +err_unload: + mutex_unlock(&cgroup_mutex); + /* @ss can't be mounted here as try_module_get() would fail */ + cgroup_unload_subsys(ss); + return ret; } EXPORT_SYMBOL_GPL(cgroup_load_subsys); @@ -4548,7 +4548,6 @@ void cgroup_unload_subsys(struct cgroup_subsys *ss) struct css_set *cg = link->cg; hlist_del(&cg->hlist); - BUG_ON(!cg->subsys[ss->subsys_id]); cg->subsys[ss->subsys_id] = NULL; hhead = css_set_hash(cg->subsys); hlist_add_head(&cg->hlist, hhead); |