sched: Use lockdep-based checking on rcu_dereference()

Update the rcu_dereference() usages to take advantage of the new
lockdep-based checking.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1266887105-1528-6-git-send-email-paulmck@linux.vnet.ibm.com>
[ -v2: fix allmodconfig missing symbol export build failure on x86 ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 14 insertions, 0 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index aa3bee566446..b1a0f5a528fe 100644
--- 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)
 {