Revert locking to 3.12 method.

-ck

---
 kernel/sched/bfs.c |    7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

Index: linux-3.15.5-ck1/kernel/sched/bfs.c
===================================================================
--- linux-3.15.5-ck1.orig/kernel/sched/bfs.c	2014-07-15 16:40:13.117251906 +1000
+++ linux-3.15.5-ck1/kernel/sched/bfs.c	2014-07-15 17:44:26.709609954 +1000
@@ -6660,17 +6660,14 @@ void __init sched_init_smp(void)
 
 	sched_init_numa();
 
-	/*
-	 * There's no userspace yet to cause hotplug operations; hence all the
-	 * cpu masks are stable and all blatant races in the below code cannot
-	 * happen.
-	 */
+	get_online_cpus();
 	mutex_lock(&sched_domains_mutex);
 	init_sched_domains(cpu_active_mask);
 	cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
 	if (cpumask_empty(non_isolated_cpus))
 		cpumask_set_cpu(smp_processor_id(), non_isolated_cpus);
 	mutex_unlock(&sched_domains_mutex);
+	put_online_cpus();
 
 	hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE);
 	hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);