linux-kernel - [PATCH v1 6/6] ACPI: processor: Do not expose global variable acpi_idle

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Message-ID: <20251223100914.2407069-7-lihuisong@huawei.com>
Date: Tue, 23 Dec 2025 18:09:14 +0800
From: Huisong Li <lihuisong@...wei.com>
To: <rafael@...nel.org>, <lenb@...nel.org>, <bp@...en8.de>,
	<AmandeepKaur.Longia@....com>
CC: <linux-acpi@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linuxarm@...wei.com>, <jonathan.cameron@...wei.com>,
	<zhanjie9@...ilicon.com>, <zhenglifeng1@...wei.com>, <yubowen8@...wei.com>,
	<zhangpengjie2@...wei.com>, <wangzhi12@...wei.com>,
	<prime.zeng@...ilicon.com>, <lihuisong@...wei.com>
Subject: [PATCH v1 6/6] ACPI: processor: Do not expose global variable acpi_idle_driver

Move the cpuidle driver check from __acpi_processor_start() to
acpi_processor_power_init() which allows variable acpi_idle_driver to
become static.

No intentional functional impact.

Signed-off-by: Huisong Li <lihuisong@...wei.com>
Link: https://patch.msgid.link/20250923032428.2656329-2-lihuisong@huawei.com
[ rjw: Subject tweak, new changelog, adjustment of a new comment ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/acpi/processor_driver.c | 3 +--
 drivers/acpi/processor_idle.c   | 9 ++++++++-
 include/acpi/processor.h        | 1 -
 3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
index f5b4f6a29143..882709796b4f 100644
--- a/drivers/acpi/processor_driver.c
+++ b/drivers/acpi/processor_driver.c
@@ -166,8 +166,7 @@ static int __acpi_processor_start(struct acpi_device *device)
 	if (result && !IS_ENABLED(CONFIG_ACPI_CPU_FREQ_PSS))
 		dev_dbg(&device->dev, "CPPC data invalid or not present\n");
 
-	if (cpuidle_get_driver() == &acpi_idle_driver)
-		acpi_processor_power_init(pr);
+	acpi_processor_power_init(pr);
 
 	acpi_pss_perf_init(pr);
 
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 05425d1b3ef7..427423e7a0c7 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -51,7 +51,7 @@ module_param(latency_factor, uint, 0644);
 
 static DEFINE_PER_CPU(struct cpuidle_device *, acpi_cpuidle_device);
 
-struct cpuidle_driver acpi_idle_driver = {
+static struct cpuidle_driver acpi_idle_driver = {
 	.name =		"acpi_idle",
 	.owner =	THIS_MODULE,
 };
@@ -1395,6 +1395,13 @@ void acpi_processor_power_init(struct acpi_processor *pr)
 {
 	struct cpuidle_device *dev;
 
+	/*
+	 * The code below only works if the current cpuidle driver is the ACPI
+	 * idle driver.
+	 */
+	if (cpuidle_get_driver() != &acpi_idle_driver)
+		return;
+
 	if (disabled_by_idle_boot_param())
 		return;
 
diff --git a/include/acpi/processor.h b/include/acpi/processor.h
index 24fdaa3c2899..7146a8e9e9c2 100644
--- a/include/acpi/processor.h
+++ b/include/acpi/processor.h
@@ -417,7 +417,6 @@ static inline void acpi_processor_throttling_init(void) {}
 #endif	/* CONFIG_ACPI_CPU_FREQ_PSS */
 
 /* in processor_idle.c */
-extern struct cpuidle_driver acpi_idle_driver;
 #ifdef CONFIG_ACPI_PROCESSOR_IDLE
 void acpi_processor_power_init(struct acpi_processor *pr);
 void acpi_processor_power_exit(struct acpi_processor *pr);
-- 
2.33.0