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| author | Tejun Heo <tj@kernel.org> | 2013-04-14 11:36:57 -0700 |
|---|---|---|
| committer | Maciej Wereski <m.wereski@partner.samsung.com> | 2014-12-22 09:16:47 +0100 |
| commit | 6a205f1ffb3fc757d8f1a7befafc9e73fb767678 (patch) | |
| tree | 741cc582576e94c8afaf40191c26a03c0978e07a | |
| parent | 2207906f36da3872ac44eac5efef59d3b2597584 (diff) | |
| download | linux-3.10-6a205f1ffb3fc757d8f1a7befafc9e73fb767678.tar.gz linux-3.10-6a205f1ffb3fc757d8f1a7befafc9e73fb767678.tar.bz2 linux-3.10-6a205f1ffb3fc757d8f1a7befafc9e73fb767678.zip | |
cgroup: drop hierarchy_id_lock
Now that hierarchy_id alloc / free are protected by the cgroup
mutexes, there's no need for this separate lock. Drop it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
| -rw-r--r-- | kernel/cgroup.c | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 8ea49c7c59a..62f95510950 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -197,9 +197,13 @@ struct cgroup_event { static LIST_HEAD(roots); static int root_count; +/* + * Hierarchy ID allocation and mapping. It follows the same exclusion + * rules as other root ops - both cgroup_mutex and cgroup_root_mutex for + * writes, either for reads. + */ static DEFINE_IDA(hierarchy_ida); static int next_hierarchy_id; -static DEFINE_SPINLOCK(hierarchy_id_lock); /* dummytop is a shorthand for the dummy hierarchy's top cgroup */ #define dummytop (&rootnode.top_cgroup) @@ -1438,10 +1442,12 @@ static int cgroup_init_root_id(struct cgroupfs_root *root) { int ret; + lockdep_assert_held(&cgroup_mutex); + lockdep_assert_held(&cgroup_root_mutex); + do { if (!ida_pre_get(&hierarchy_ida, GFP_KERNEL)) return -ENOMEM; - spin_lock(&hierarchy_id_lock); /* Try to allocate the next unused ID */ ret = ida_get_new_above(&hierarchy_ida, next_hierarchy_id, &root->hierarchy_id); @@ -1454,18 +1460,17 @@ static int cgroup_init_root_id(struct cgroupfs_root *root) /* Can only get here if the 31-bit IDR is full ... */ BUG_ON(ret); } - spin_unlock(&hierarchy_id_lock); } while (ret); return 0; } static void cgroup_exit_root_id(struct cgroupfs_root *root) { + lockdep_assert_held(&cgroup_mutex); + lockdep_assert_held(&cgroup_root_mutex); + if (root->hierarchy_id) { - spin_lock(&hierarchy_id_lock); ida_remove(&hierarchy_ida, root->hierarchy_id); - spin_unlock(&hierarchy_id_lock); - root->hierarchy_id = 0; } } @@ -4685,8 +4690,14 @@ int __init cgroup_init(void) hash_add(css_set_table, &init_css_set.hlist, key); /* allocate id for the dummy hierarchy */ + mutex_lock(&cgroup_mutex); + mutex_lock(&cgroup_root_mutex); + BUG_ON(cgroup_init_root_id(&rootnode)); + mutex_unlock(&cgroup_root_mutex); + mutex_unlock(&cgroup_mutex); + cgroup_kobj = kobject_create_and_add("cgroup", fs_kobj); if (!cgroup_kobj) { err = -ENOMEM; |