linux-kernel - [PATCH v4] cpuidle: Init cpuidle only for present CPUs

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Message-Id: <20250307080303.2660506-1-ping.bai@nxp.com>
Date: Fri,  7 Mar 2025 16:03:03 +0800
From: Jacky Bai <ping.bai@....com>
To: rafael@...nel.org,
	daniel.lezcano@...aro.org,
	lpieralisi@...nel.org,
	sudeep.holla@....com,
	ulf.hansson@...aro.org,
	james.morse@....com,
	d-gole@...com,
	anup@...infault.org,
	paul.walmsley@...ive.com,
	palmer@...belt.com,
	aou@...s.berkeley.edu
Cc: linux-pm@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	linux-riscv@...ts.infradead.org,
	imx@...ts.linux.dev,
	khilman@...libre.com,
	quic_tingweiz@...cinc.com,
	quic_yuanjiey@...cinc.com
Subject: [PATCH v4] cpuidle: Init cpuidle only for present CPUs

for_each_possible_cpu() is currently used to initialize cpuidle
in below cpuidle drivers:
  drivers/cpuidle/cpuidle-arm.c
  drivers/cpuidle/cpuidle-big_little.c
  drivers/cpuidle/cpuidle-psci.c
  drivers/cpuidle/cpuidle-riscv-sbi.c

However, in cpu_dev_register_generic(), for_each_present_cpu()
is used to register CPU devices which means the CPU devices are
only registered for present CPUs and not all possible CPUs.

With nosmp or maxcpus=0, only the boot CPU is present, lead
to the failure:

  |  Failed to register cpuidle device for cpu1

Then rollback to cancel all CPUs' cpuidle registration.

Change for_each_possible_cpu() to for_each_present_cpu() in the
above cpuidle drivers to ensure it only registers cpuidle devices
for CPUs that are actually present.

Fixes: b0c69e1214bc ("drivers: base: Use present CPUs in GENERIC_CPU_DEVICES")
Reviewed-by: Dhruva Gole <d-gole@...com>
Reviewed-by: Sudeep Holla <sudeep.holla@....com>
Tested-by: Yuanjie Yang <quic_yuanjiey@...cinc.com>
Signed-off-by: Jacky Bai <ping.bai@....com>
---
 - v4 changes:
  - add changes for other cpuidle driver that has the similar issue
    as cpuidle-pcsi driver.

 - v3 changes:
  - improve the changelog as suggested by Sudeep
---
 drivers/cpuidle/cpuidle-arm.c        | 8 ++++----
 drivers/cpuidle/cpuidle-big_little.c | 2 +-
 drivers/cpuidle/cpuidle-psci.c       | 4 ++--
 drivers/cpuidle/cpuidle-riscv-sbi.c  | 4 ++--
 4 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/cpuidle/cpuidle-arm.c b/drivers/cpuidle/cpuidle-arm.c
index caba6f4bb1b7..e044fefdb816 100644
--- a/drivers/cpuidle/cpuidle-arm.c
+++ b/drivers/cpuidle/cpuidle-arm.c
@@ -137,9 +137,9 @@ static int __init arm_idle_init_cpu(int cpu)
 /*
  * arm_idle_init - Initializes arm cpuidle driver
  *
- * Initializes arm cpuidle driver for all CPUs, if any CPU fails
- * to register cpuidle driver then rollback to cancel all CPUs
- * registration.
+ * Initializes arm cpuidle driver for all present CPUs, if any
+ * CPU fails to register cpuidle driver then rollback to cancel
+ * all CPUs registration.
  */
 static int __init arm_idle_init(void)
 {
@@ -147,7 +147,7 @@ static int __init arm_idle_init(void)
 	struct cpuidle_driver *drv;
 	struct cpuidle_device *dev;
 
-	for_each_possible_cpu(cpu) {
+	for_each_present_cpu(cpu) {
 		ret = arm_idle_init_cpu(cpu);
 		if (ret)
 			goto out_fail;
diff --git a/drivers/cpuidle/cpuidle-big_little.c b/drivers/cpuidle/cpuidle-big_little.c
index 74972deda0ea..4abba42fcc31 100644
--- a/drivers/cpuidle/cpuidle-big_little.c
+++ b/drivers/cpuidle/cpuidle-big_little.c
@@ -148,7 +148,7 @@ static int __init bl_idle_driver_init(struct cpuidle_driver *drv, int part_id)
 	if (!cpumask)
 		return -ENOMEM;
 
-	for_each_possible_cpu(cpu)
+	for_each_present_cpu(cpu)
 		if (smp_cpuid_part(cpu) == part_id)
 			cpumask_set_cpu(cpu, cpumask);
 
diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c
index dd8d776d6e39..b46a83f5ffe4 100644
--- a/drivers/cpuidle/cpuidle-psci.c
+++ b/drivers/cpuidle/cpuidle-psci.c
@@ -403,7 +403,7 @@ static int psci_idle_init_cpu(struct device *dev, int cpu)
 /*
  * psci_idle_probe - Initializes PSCI cpuidle driver
  *
- * Initializes PSCI cpuidle driver for all CPUs, if any CPU fails
+ * Initializes PSCI cpuidle driver for all present CPUs, if any CPU fails
  * to register cpuidle driver then rollback to cancel all CPUs
  * registration.
  */
@@ -413,7 +413,7 @@ static int psci_cpuidle_probe(struct platform_device *pdev)
 	struct cpuidle_driver *drv;
 	struct cpuidle_device *dev;
 
-	for_each_possible_cpu(cpu) {
+	for_each_present_cpu(cpu) {
 		ret = psci_idle_init_cpu(&pdev->dev, cpu);
 		if (ret)
 			goto out_fail;
diff --git a/drivers/cpuidle/cpuidle-riscv-sbi.c b/drivers/cpuidle/cpuidle-riscv-sbi.c
index 0c92a628bbd4..0fe1ece9fbdc 100644
--- a/drivers/cpuidle/cpuidle-riscv-sbi.c
+++ b/drivers/cpuidle/cpuidle-riscv-sbi.c
@@ -529,8 +529,8 @@ static int sbi_cpuidle_probe(struct platform_device *pdev)
 			return ret;
 	}
 
-	/* Initialize CPU idle driver for each CPU */
-	for_each_possible_cpu(cpu) {
+	/* Initialize CPU idle driver for each present CPU */
+	for_each_present_cpu(cpu) {
 		ret = sbi_cpuidle_init_cpu(&pdev->dev, cpu);
 		if (ret) {
 			pr_debug("HART%ld: idle driver init failed\n",
-- 
2.34.1