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Date: Thu, 17 Nov 2016 19:35:23 +0100
From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To: linux-kernel@...r.kernel.org
Cc: rt@...uxtronix.de,
Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
x86@...nel.org, Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH 02/20] x86/cpuid: Convert to hotplug state machine
Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.
Cc: x86@...nel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
arch/x86/kernel/cpuid.c | 54 ++++++++--------------------------------------
include/linux/cpuhotplug.h | 1 +
2 files changed, 10 insertions(+), 45 deletions(-)
diff --git a/arch/x86/kernel/cpuid.c b/arch/x86/kernel/cpuid.c
index 2836de390f95..eaa272454fe4 100644
--- a/arch/x86/kernel/cpuid.c
+++ b/arch/x86/kernel/cpuid.c
@@ -115,7 +115,7 @@ static const struct file_operations cpuid_fops = {
.open = cpuid_open,
};
-static int cpuid_device_create(int cpu)
+static int cpuid_device_create(unsigned int cpu)
{
struct device *dev;
@@ -124,35 +124,12 @@ static int cpuid_device_create(int cpu)
return PTR_ERR_OR_ZERO(dev);
}
-static void cpuid_device_destroy(int cpu)
+static int cpuid_device_destroy(unsigned int cpu)
{
device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
+ return 0;
}
-static int cpuid_class_cpu_callback(struct notifier_block *nfb,
- unsigned long action, void *hcpu)
-{
- unsigned int cpu = (unsigned long)hcpu;
- int err = 0;
-
- switch (action) {
- case CPU_UP_PREPARE:
- err = cpuid_device_create(cpu);
- break;
- case CPU_UP_CANCELED:
- case CPU_UP_CANCELED_FROZEN:
- case CPU_DEAD:
- cpuid_device_destroy(cpu);
- break;
- }
- return notifier_from_errno(err);
-}
-
-static struct notifier_block cpuid_class_cpu_notifier =
-{
- .notifier_call = cpuid_class_cpu_callback,
-};
-
static char *cpuid_devnode(struct device *dev, umode_t *mode)
{
return kasprintf(GFP_KERNEL, "cpu/%u/cpuid", MINOR(dev->devt));
@@ -177,24 +154,17 @@ static int __init cpuid_init(void)
}
cpuid_class->devnode = cpuid_devnode;
- cpu_notifier_register_begin();
- for_each_online_cpu(i) {
- err = cpuid_device_create(i);
- if (err != 0)
- goto out_class;
- }
- __register_hotcpu_notifier(&cpuid_class_cpu_notifier);
- cpu_notifier_register_done();
+ err = cpuhp_setup_state(CPUHP_X86_CPUID_PREPARE, "x86/cpuid:prepare",
+ cpuid_device_create, cpuid_device_destroy);
+ if (err)
+ goto out_class;
err = 0;
goto out;
out_class:
i = 0;
- for_each_online_cpu(i) {
- cpuid_device_destroy(i);
- }
- cpu_notifier_register_done();
+ cpuhp_remove_state(CPUHP_X86_CPUID_PREPARE);
class_destroy(cpuid_class);
out_chrdev:
__unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
@@ -204,15 +174,9 @@ static int __init cpuid_init(void)
static void __exit cpuid_exit(void)
{
- int cpu = 0;
-
- cpu_notifier_register_begin();
- for_each_online_cpu(cpu)
- cpuid_device_destroy(cpu);
+ cpuhp_remove_state(CPUHP_X86_CPUID_PREPARE);
class_destroy(cpuid_class);
__unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
- __unregister_hotcpu_notifier(&cpuid_class_cpu_notifier);
- cpu_notifier_register_done();
}
module_init(cpuid_init);
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index aea6c6a63139..2f9e083791c4 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -60,6 +60,7 @@ enum cpuhp_state {
CPUHP_NET_FLOW_PREPARE,
CPUHP_TOPOLOGY_PREPARE,
CPUHP_X86_THERM_PREPARE,
+ CPUHP_X86_CPUID_PREPARE,
CPUHP_TIMERS_DEAD,
CPUHP_NOTF_ERR_INJ_PREPARE,
CPUHP_MIPS_SOC_PREPARE,
--
2.10.2
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