sched: Use lockdep-based checking on rcu_dereference()

[mirror_ubuntu-zesty-kernel.git] / kernel / cgroup.c

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 1fbcc748044a7f3dc367381838289ecce3992652..b1a0f5a528fe6563badc393f96db9e4cfa2d9255 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -166,6 +166,20 @@ static DEFINE_SPINLOCK(hierarchy_id_lock);
  */
 static int need_forkexit_callback __read_mostly;
 
+#ifdef CONFIG_PROVE_LOCKING
+int cgroup_lock_is_held(void)
+{
+       return lockdep_is_held(&cgroup_mutex);
+}
+#else /* #ifdef CONFIG_PROVE_LOCKING */
+int cgroup_lock_is_held(void)
+{
+       return mutex_is_locked(&cgroup_mutex);
+}
+#endif /* #else #ifdef CONFIG_PROVE_LOCKING */
+
+EXPORT_SYMBOL_GPL(cgroup_lock_is_held);
+
 /* convenient tests for these bits */
 inline int cgroup_is_removed(const struct cgroup *cgrp)
 {
@@ -2936,14 +2950,17 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
 
        for_each_subsys(root, ss) {
                struct cgroup_subsys_state *css = ss->create(ss, cgrp);
+
                if (IS_ERR(css)) {
                        err = PTR_ERR(css);
                        goto err_destroy;
                }
                init_cgroup_css(css, ss, cgrp);
-               if (ss->use_id)
-                       if (alloc_css_id(ss, parent, cgrp))
+               if (ss->use_id) {
+                       err = alloc_css_id(ss, parent, cgrp);
+                       if (err)
                                goto err_destroy;
+               }
                /* At error, ->destroy() callback has to free assigned ID. */
        }