linux-kernel - [PATCH] x86/tsc: fold set_cyc2ns

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Date:   Wed, 17 May 2017 22:39:24 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     Arnd Bergmann <arnd@...db.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        Prarit Bhargava <prarit@...hat.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH] x86/tsc: fold set_cyc2ns_scale() into caller

The newly introduced wrapper function only has one caller,
and this one is conditional, causing a harmless warning when
CONFIG_CPU_FREQ is disabled:

arch/x86/kernel/tsc.c:189:13: error: 'set_cyc2ns_scale' defined but not used [-Werror=unused-function]

My first idea was to move the wrapper inside of that #ifdef,
but on second thought it seemed nicer to remove it completely
again and rename __set_cyc2ns_scale back to set_cyc2ns_scale,
but leaving the extra argument.

Fixes: 615cd03373a0 ("x86/tsc: Fix sched_clock() sync")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 arch/x86/kernel/tsc.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index a3b544264360..5270fc0c2df6 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -137,7 +137,7 @@ static inline unsigned long long cycles_2_ns(unsigned long long cyc)
 	return ns;
 }
 
-static void __set_cyc2ns_scale(unsigned long khz, int cpu, unsigned long long tsc_now)
+static void set_cyc2ns_scale(unsigned long khz, int cpu, unsigned long long tsc_now)
 {
 	unsigned long long ns_now;
 	struct cyc2ns_data data;
@@ -186,11 +186,6 @@ static void __set_cyc2ns_scale(unsigned long khz, int cpu, unsigned long long ts
 	local_irq_restore(flags);
 }
 
-static void set_cyc2ns_scale(unsigned long khz, int cpu)
-{
-	__set_cyc2ns_scale(khz, cpu, rdtsc());
-}
-
 /*
  * Scheduler clock - returns current time in nanosec units.
  */
@@ -892,7 +887,6 @@ void tsc_restore_sched_clock_state(void)
 }
 
 #ifdef CONFIG_CPU_FREQ
-
 /* Frequency scaling support. Adjust the TSC based timer when the cpu frequency
  * changes.
  *
@@ -933,7 +927,7 @@ static int time_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
 		if (!(freq->flags & CPUFREQ_CONST_LOOPS))
 			mark_tsc_unstable("cpufreq changes");
 
-		set_cyc2ns_scale(tsc_khz, freq->cpu);
+		set_cyc2ns_scale(tsc_khz, freq->cpu, rdtsc());
 	}
 
 	return 0;
@@ -1224,7 +1218,7 @@ static void tsc_refine_calibration_work(struct work_struct *work)
 
 	/* Update the sched_clock() rate to match the clocksource one */
 	for_each_possible_cpu(cpu)
-		__set_cyc2ns_scale(tsc_khz, cpu, tsc_stop);
+		set_cyc2ns_scale(tsc_khz, cpu, tsc_stop);
 
 out:
 	if (boot_cpu_has(X86_FEATURE_ART))
@@ -1314,7 +1308,7 @@ void __init tsc_init(void)
 	cyc = rdtsc();
 	for_each_possible_cpu(cpu) {
 		cyc2ns_init(cpu);
-		__set_cyc2ns_scale(tsc_khz, cpu, cyc);
+		set_cyc2ns_scale(tsc_khz, cpu, cyc);
 	}
 
 	if (tsc_disabled > 0)
-- 
2.9.0