* 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)
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;
}
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;
}
}