From e129d7add80af175e0937f1e72dde0e0bf937140 Mon Sep 17 00:00:00 2001
From: Viresh Kumar <viresh.kumar@linaro.org>
Date: Mon, 20 Jan 2020 11:29:05 +0530
Subject: [PATCH] sched/fair: Define sched_idle_cpu() only for SMP
 configurations
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References: bnc#1155798 (CPU scheduler functional and performance backports)
Patch-mainline: v5.6-rc1
Git-commit: afa70d941f663c69c9a64ec1021bbcfa82f0e54a

sched_idle_cpu() isn't used for non SMP configuration and with a recent
change, we have started getting following warning:

  kernel/sched/fair.c:5221:12: warning: ‘sched_idle_cpu’ defined but not used [-Wunused-function]

Fix that by defining sched_idle_cpu() only for SMP configurations.

Fixes: 323af6deaf70 ("sched/fair: Load balance aggressively for SCHED_IDLE CPUs")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/f0554f590687478b33914a4aff9f0e6a62886d44.1579499907.git.viresh.kumar@linaro.org
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
 kernel/sched/fair.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 61939fda87a5..1f67bc82fa6d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5220,10 +5220,12 @@ static int sched_idle_rq(struct rq *rq)
 			rq->nr_running);
 }
 
+#ifdef CONFIG_SMP
 static int sched_idle_cpu(int cpu)
 {
 	return sched_idle_rq(cpu_rq(cpu));
 }
+#endif
 
 /*
  * The enqueue_task method is called before nr_running is