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| author |   Tejun Heo <tj@kernel.org> | 2013-04-14 11:36:58 -0700 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2013-05-14 11:42:07 -0700 |
| commit | 1a574231669f8c3065c83974e9557fcbbd94b8a6 (patch) | |
| tree | 1f2f0bc767f0fae3c5e5c28e3274733d4bf0fb07 /kernel/cgroup.c | |
| parent | cgroup: drop hierarchy_id_lock (diff) | |
| download | linux-dev-1a574231669f8c3065c83974e9557fcbbd94b8a6.tar.xz linux-dev-1a574231669f8c3065c83974e9557fcbbd94b8a6.zip | |
cgroup: make hierarchy_id use cyclic idr
We want to be able to lookup a hierarchy from its id and cyclic
allocation is a whole lot simpler with idr. Convert to idr and use
idr_alloc_cyclc().
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 28 |
1 files changed, 8 insertions, 20 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 3ef677d314bc..dcb417c6c242 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -194,8 +194,7 @@ static int root_count; * 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_IDR(cgroup_hierarchy_idr); /* dummytop is a shorthand for the dummy hierarchy's top cgroup */ #define dummytop (&rootnode.top_cgroup) @@ -1432,27 +1431,16 @@ static void init_cgroup_root(struct cgroupfs_root *root) static int cgroup_init_root_id(struct cgroupfs_root *root) { - int ret; + int id; lockdep_assert_held(&cgroup_mutex); lockdep_assert_held(&cgroup_root_mutex); - do { - if (!ida_pre_get(&hierarchy_ida, GFP_KERNEL)) - return -ENOMEM; - /* Try to allocate the next unused ID */ - ret = ida_get_new_above(&hierarchy_ida, next_hierarchy_id, - &root->hierarchy_id); - if (ret == -ENOSPC) - /* Try again starting from 0 */ - ret = ida_get_new(&hierarchy_ida, &root->hierarchy_id); - if (!ret) { - next_hierarchy_id = root->hierarchy_id + 1; - } else if (ret != -EAGAIN) { - /* Can only get here if the 31-bit IDR is full ... */ - BUG_ON(ret); - } - } while (ret); + id = idr_alloc_cyclic(&cgroup_hierarchy_idr, root, 2, 0, GFP_KERNEL); + if (id < 0) + return id; + + root->hierarchy_id = id; return 0; } @@ -1462,7 +1450,7 @@ static void cgroup_exit_root_id(struct cgroupfs_root *root) lockdep_assert_held(&cgroup_root_mutex); if (root->hierarchy_id) { - ida_remove(&hierarchy_ida, root->hierarchy_id); + idr_remove(&cgroup_hierarchy_idr, root->hierarchy_id); root->hierarchy_id = 0; } } |