sibling_cpu_map may be undefined till later in boot process so use blank
placeholders for smt sibling test functions until sched_smp_init is completing.

-ck

---
 kernel/sched/bfs.c |   45 ++++++++++++++++++++++++++++-----------------
 1 file changed, 28 insertions(+), 17 deletions(-)

Index: linux-4.7-ck4/kernel/sched/bfs.c
===================================================================
--- linux-4.7-ck4.orig/kernel/sched/bfs.c	2016-09-13 17:21:51.054277143 +1000
+++ linux-4.7-ck4/kernel/sched/bfs.c	2016-09-13 17:21:51.052277189 +1000
@@ -818,6 +818,13 @@ static int task_prio_bias(struct task_st
 	return MAX_PRIO - p->static_prio;
 }
 
+static bool smt_always_schedule(struct task_struct __maybe_unused *p, int __maybe_unused cpu)
+{
+	return true;
+}
+
+static bool (*smt_schedule)(struct task_struct __maybe_unused *p, int __maybe_unused cpu) = &smt_always_schedule;
+
 /* We've already decided p can run on CPU, now test if it shouldn't for SMT
  * nice reasons. */
 static bool smt_should_schedule(struct task_struct *p, int cpu)
@@ -847,7 +854,7 @@ static bool smt_should_schedule(struct t
 	return false;
 }
 #else
-#define smt_should_schedule(p, cpu) (1)
+#define smt_schedule(p, cpu) (true)
 #endif
 
 static bool resched_best_idle(struct task_struct *p)
@@ -857,10 +864,8 @@ static bool resched_best_idle(struct tas
 
 	cpumask_and(&tmpmask, &p->cpus_allowed, &grq.cpu_idle_map);
 	best_cpu = best_mask_cpu(task_cpu(p), task_rq(p), &tmpmask);
-#ifdef CONFIG_SMT_NICE
-	if (!smt_should_schedule(p, best_cpu))
+	if (!smt_schedule(p, best_cpu))
 		return false;
-#endif
 	resched_curr(cpu_rq(best_cpu));
 	return true;
 }
@@ -1400,7 +1405,7 @@ static void try_preempt(struct task_stru
 	/* See if this task can preempt the task on the current CPU first. */
 	cpu = cpu_of(this_rq);
 	if (cpumask_test_cpu(cpu, &tmp)) {
-		if (smt_should_schedule(p, cpu) && can_preempt(p, this_rq->rq_prio, this_rq->rq_deadline)) {
+		if (smt_schedule(p, cpu) && can_preempt(p, this_rq->rq_prio, this_rq->rq_deadline)) {
 			resched_curr(this_rq);
 			return;
 		}
@@ -1429,10 +1434,8 @@ static void try_preempt(struct task_stru
 
 	if (likely(highest_prio_rq)) {
 		cpu = cpu_of(highest_prio_rq);
-#ifdef CONFIG_SMT_NICE
-		if (!smt_should_schedule(p, cpu))
+		if (!smt_schedule(p, cpu))
 			return;
-#endif
 		if (can_preempt(p, highest_prio, latest_deadline)) {
 			/*
 			 * If we have decided this task should preempt this CPU,
@@ -3316,10 +3319,8 @@ task_struct *earliest_deadline_task(stru
 		if (needs_other_cpu(p, cpu))
 			continue;
 
-#ifdef CONFIG_SMT_NICE
-		if (!smt_should_schedule(p, cpu))
+		if (!smt_schedule(p, cpu))
 			continue;
-#endif
 
 		if (!sched_interactive && (tcpu = task_cpu(p)) != cpu) {
 			u64 dl;
@@ -3426,6 +3427,11 @@ static void reset_rq_task(struct rq *rq,
 }
 
 #ifdef CONFIG_SMT_NICE
+static void check_no_siblings(int __maybe_unused cpu) {}
+static void wake_no_siblings(int __maybe_unused cpu) {}
+static void (*check_siblings)(int) = &check_no_siblings;
+static void (*wake_siblings)(int) = &wake_no_siblings;
+
 /* Iterate over smt siblings when we've scheduled a process on cpu and decide
  * whether they should continue running or be descheduled. */
 static void check_smt_siblings(int cpu)
@@ -3473,8 +3479,8 @@ static void wake_smt_siblings(int cpu)
 	}
 }
 #else
-static void check_smt_siblings(int __maybe_unused cpu) {}
-static void wake_smt_siblings(int __maybe_unused cpu) {}
+static void check_siblings(int __maybe_unused cpu) {}
+static void wake_siblings(int __maybe_unused cpu) {}
 #endif
 
 /*
@@ -3611,7 +3617,7 @@ static void __sched notrace __schedule(b
 					 * again.
 					 */
 					set_rq_task(rq, prev);
-					check_smt_siblings(cpu);
+					check_siblings(cpu);
 					grq_unlock_irq();
 					goto rerun_prev_unlocked;
 				} else
@@ -3651,9 +3657,9 @@ static void __sched notrace __schedule(b
 			unstick_task(rq, prev);
 		set_rq_task(rq, next);
 		if (next != idle)
-			check_smt_siblings(cpu);
+			check_siblings(cpu);
 		else
-			wake_smt_siblings(cpu);
+			wake_siblings(cpu);
 		grq.nr_switches++;
 		prev->on_cpu = false;
 		next->on_cpu = true;
@@ -3665,7 +3671,7 @@ static void __sched notrace __schedule(b
 		cpu = cpu_of(rq);
 		idle = rq->idle;
 	} else {
-		check_smt_siblings(cpu);
+		check_siblings(cpu);
 		grq_unlock_irq();
 	}
 
@@ -7191,6 +7197,11 @@ void __init sched_init_smp(void)
 			rq->siblings_idle = siblings_cpu_idle;
 #endif
 	}
+#ifdef CONFIG_SMT_NICE
+	check_siblings = &check_smt_siblings;
+	wake_siblings = &wake_smt_siblings;
+	smt_schedule = &smt_should_schedule;
+#endif
 	grq_unlock_irq();
 	mutex_unlock(&sched_domains_mutex);