[PATCH 01/20] x86/mce/therm_throt: Convert to hotplug state machine

From: Sebastian Andrzej Siewior
Date: Thu Nov 17 2016 - 13:40:35 EST


Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: linux-edac@xxxxxxxxxxxxxxx
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/mcheck/therm_throt.c | 53 ++++++++------------------------
include/linux/cpuhotplug.h | 1 +
2 files changed, 13 insertions(+), 41 deletions(-)

diff --git a/arch/x86/kernel/cpu/mcheck/therm_throt.c b/arch/x86/kernel/cpu/mcheck/therm_throt.c
index 6b9dc4d18ccc..7f56620735ca 100644
--- a/arch/x86/kernel/cpu/mcheck/therm_throt.c
+++ b/arch/x86/kernel/cpu/mcheck/therm_throt.c
@@ -271,58 +271,29 @@ static void thermal_throttle_remove_dev(struct device *dev)
}

/* Get notified when a cpu comes on/off. Be hotplug friendly. */
-static int
-thermal_throttle_cpu_callback(struct notifier_block *nfb,
- unsigned long action,
- void *hcpu)
+static int thermal_throttle_prepare(unsigned int cpu)
{
- unsigned int cpu = (unsigned long)hcpu;
- struct device *dev;
- int err = 0;
+ struct device *dev = get_cpu_device(cpu);

- dev = get_cpu_device(cpu);
-
- switch (action) {
- case CPU_UP_PREPARE:
- case CPU_UP_PREPARE_FROZEN:
- err = thermal_throttle_add_dev(dev, cpu);
- WARN_ON(err);
- break;
- case CPU_UP_CANCELED:
- case CPU_UP_CANCELED_FROZEN:
- case CPU_DEAD:
- case CPU_DEAD_FROZEN:
- thermal_throttle_remove_dev(dev);
- break;
- }
- return notifier_from_errno(err);
+ return thermal_throttle_add_dev(dev, cpu);
}

-static struct notifier_block thermal_throttle_cpu_notifier =
+static int thermal_throttle_dead(unsigned int cpu)
{
- .notifier_call = thermal_throttle_cpu_callback,
-};
+ struct device *dev = get_cpu_device(cpu);
+
+ thermal_throttle_remove_dev(dev);
+ return 0;
+}

static __init int thermal_throttle_init_device(void)
{
- unsigned int cpu = 0;
- int err;
-
if (!atomic_read(&therm_throt_en))
return 0;

- cpu_notifier_register_begin();
-
- /* connect live CPUs to sysfs */
- for_each_online_cpu(cpu) {
- err = thermal_throttle_add_dev(get_cpu_device(cpu), cpu);
- WARN_ON(err);
- }
-
- __register_hotcpu_notifier(&thermal_throttle_cpu_notifier);
- cpu_notifier_register_done();
-
- return 0;
+ return cpuhp_setup_state(CPUHP_X86_THERM_PREPARE, "x86/therm:prepare",
+ thermal_throttle_prepare,
+ thermal_throttle_dead);
}
device_initcall(thermal_throttle_init_device);

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 79b96f647d64..aea6c6a63139 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -59,6 +59,7 @@ enum cpuhp_state {
CPUHP_BLK_MQ_PREPARE,
CPUHP_NET_FLOW_PREPARE,
CPUHP_TOPOLOGY_PREPARE,
+ CPUHP_X86_THERM_PREPARE,
CPUHP_TIMERS_DEAD,
CPUHP_NOTF_ERR_INJ_PREPARE,
CPUHP_MIPS_SOC_PREPARE,
--
2.10.2