Merge branch 'akpm' (Andrew's patch-bomb)
[~shefty/rdma-dev.git] / kernel / cgroup.c
index 1ece8e20fdb50b4109bf1d99a1e465808863568a..f4ea4b6f3cf1eae8725ab6107f20bab58324f103 100644 (file)
@@ -4881,9 +4881,9 @@ void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css)
 
        rcu_assign_pointer(id->css, NULL);
        rcu_assign_pointer(css->id, NULL);
-       write_lock(&ss->id_lock);
+       spin_lock(&ss->id_lock);
        idr_remove(&ss->idr, id->id);
-       write_unlock(&ss->id_lock);
+       spin_unlock(&ss->id_lock);
        kfree_rcu(id, rcu_head);
 }
 EXPORT_SYMBOL_GPL(free_css_id);
@@ -4909,10 +4909,10 @@ static struct css_id *get_new_cssid(struct cgroup_subsys *ss, int depth)
                error = -ENOMEM;
                goto err_out;
        }
-       write_lock(&ss->id_lock);
+       spin_lock(&ss->id_lock);
        /* Don't use 0. allocates an ID of 1-65535 */
        error = idr_get_new_above(&ss->idr, newid, 1, &myid);
-       write_unlock(&ss->id_lock);
+       spin_unlock(&ss->id_lock);
 
        /* Returns error when there are no free spaces for new ID.*/
        if (error) {
@@ -4927,9 +4927,9 @@ static struct css_id *get_new_cssid(struct cgroup_subsys *ss, int depth)
        return newid;
 remove_idr:
        error = -ENOSPC;
-       write_lock(&ss->id_lock);
+       spin_lock(&ss->id_lock);
        idr_remove(&ss->idr, myid);
-       write_unlock(&ss->id_lock);
+       spin_unlock(&ss->id_lock);
 err_out:
        kfree(newid);
        return ERR_PTR(error);
@@ -4941,7 +4941,7 @@ static int __init_or_module cgroup_init_idr(struct cgroup_subsys *ss,
 {
        struct css_id *newid;
 
-       rwlock_init(&ss->id_lock);
+       spin_lock_init(&ss->id_lock);
        idr_init(&ss->idr);
 
        newid = get_new_cssid(ss, 0);
@@ -5029,6 +5029,8 @@ css_get_next(struct cgroup_subsys *ss, int id,
                return NULL;
 
        BUG_ON(!ss->use_id);
+       WARN_ON_ONCE(!rcu_read_lock_held());
+
        /* fill start point for scan */
        tmpid = id;
        while (1) {
@@ -5036,10 +5038,7 @@ css_get_next(struct cgroup_subsys *ss, int id,
                 * scan next entry from bitmap(tree), tmpid is updated after
                 * idr_get_next().
                 */
-               read_lock(&ss->id_lock);
                tmp = idr_get_next(&ss->idr, &tmpid);
-               read_unlock(&ss->id_lock);
-
                if (!tmp)
                        break;
                if (tmp->depth >= depth && tmp->stack[depth] == rootid) {