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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2016-11-17 21:35:24 +0300
committerThomas Gleixner <tglx@linutronix.de>2016-11-23 01:34:39 +0300
commit8fba38c937cd585bcf562fda8db3decb25509506 (patch)
tree973a8b90fee900ee9aa03f7401a0cf5d9472ce5e /arch/x86/kernel/msr.c
parentee92be9b0d7ad34cb58b61d5c0933d2e5ff7c31d (diff)
downloadlinux-8fba38c937cd585bcf562fda8db3decb25509506.tar.xz
x86/msr: Convert to hotplug state machine
Install the callbacks via the state machine and let the core invoke the callbacks on the already online CPUs. Move the callbacks to online/offline as there is no point in having the files around before the cpu is online and until its completely gone. [ tglx: Move the callbacks to online/offline ] Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: rt@linuxtronix.de Link: http://lkml.kernel.org/r/20161117183541.8588-4-bigeasy@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/kernel/msr.c')
-rw-r--r--arch/x86/kernel/msr.c69
1 files changed, 15 insertions, 54 deletions
diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c
index 7f3550acde1b..f5e3ff835cc8 100644
--- a/arch/x86/kernel/msr.c
+++ b/arch/x86/kernel/msr.c
@@ -44,6 +44,7 @@
#include <asm/msr.h>
static struct class *msr_class;
+static enum cpuhp_state cpuhp_msr_state;
static ssize_t msr_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
@@ -180,7 +181,7 @@ static const struct file_operations msr_fops = {
.compat_ioctl = msr_ioctl,
};
-static int msr_device_create(int cpu)
+static int msr_device_create(unsigned int cpu)
{
struct device *dev;
@@ -189,34 +190,12 @@ static int msr_device_create(int cpu)
return PTR_ERR_OR_ZERO(dev);
}
-static void msr_device_destroy(int cpu)
+static int msr_device_destroy(unsigned int cpu)
{
device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));
+ return 0;
}
-static int msr_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 = msr_device_create(cpu);
- break;
- case CPU_UP_CANCELED:
- case CPU_UP_CANCELED_FROZEN:
- case CPU_DEAD:
- msr_device_destroy(cpu);
- break;
- }
- return notifier_from_errno(err);
-}
-
-static struct notifier_block __refdata msr_class_cpu_notifier = {
- .notifier_call = msr_class_cpu_callback,
-};
-
static char *msr_devnode(struct device *dev, umode_t *mode)
{
return kasprintf(GFP_KERNEL, "cpu/%u/msr", MINOR(dev->devt));
@@ -224,13 +203,11 @@ static char *msr_devnode(struct device *dev, umode_t *mode)
static int __init msr_init(void)
{
- int i, err = 0;
- i = 0;
+ int err;
if (__register_chrdev(MSR_MAJOR, 0, NR_CPUS, "cpu/msr", &msr_fops)) {
pr_err("unable to get major %d for msr\n", MSR_MAJOR);
- err = -EBUSY;
- goto out;
+ return -EBUSY;
}
msr_class = class_create(THIS_MODULE, "msr");
if (IS_ERR(msr_class)) {
@@ -239,44 +216,28 @@ static int __init msr_init(void)
}
msr_class->devnode = msr_devnode;
- cpu_notifier_register_begin();
- for_each_online_cpu(i) {
- err = msr_device_create(i);
- if (err != 0)
- goto out_class;
- }
- __register_hotcpu_notifier(&msr_class_cpu_notifier);
- cpu_notifier_register_done();
-
- err = 0;
- goto out;
+ err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/msr:online",
+ msr_device_create, msr_device_destroy);
+ if (err < 0)
+ goto out_class;
+ cpuhp_msr_state = err;
+ return 0;
out_class:
- i = 0;
- for_each_online_cpu(i)
- msr_device_destroy(i);
- cpu_notifier_register_done();
+ cpuhp_remove_state(cpuhp_msr_state);
class_destroy(msr_class);
out_chrdev:
__unregister_chrdev(MSR_MAJOR, 0, NR_CPUS, "cpu/msr");
-out:
return err;
}
+module_init(msr_init);
static void __exit msr_exit(void)
{
- int cpu = 0;
-
- cpu_notifier_register_begin();
- for_each_online_cpu(cpu)
- msr_device_destroy(cpu);
+ cpuhp_remove_state(cpuhp_msr_state);
class_destroy(msr_class);
__unregister_chrdev(MSR_MAJOR, 0, NR_CPUS, "cpu/msr");
- __unregister_hotcpu_notifier(&msr_class_cpu_notifier);
- cpu_notifier_register_done();
}
-
-module_init(msr_init);
module_exit(msr_exit)
MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");