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. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: rt@linuxtronix.de Link: http://lkml.kernel.org/r/20161117183541.8588-3-bigeasy@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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@ -115,7 +115,7 @@ static const struct file_operations cpuid_fops = {
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.open = cpuid_open,
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};
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static int cpuid_device_create(int cpu)
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static int cpuid_device_create(unsigned int cpu)
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{
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struct device *dev;
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@ -124,35 +124,12 @@ static int cpuid_device_create(int cpu)
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return PTR_ERR_OR_ZERO(dev);
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}
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static void cpuid_device_destroy(int cpu)
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static int cpuid_device_destroy(unsigned int cpu)
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{
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device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
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return 0;
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}
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static int cpuid_class_cpu_callback(struct notifier_block *nfb,
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unsigned long action, void *hcpu)
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{
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unsigned int cpu = (unsigned long)hcpu;
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int err = 0;
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switch (action) {
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case CPU_UP_PREPARE:
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err = cpuid_device_create(cpu);
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break;
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case CPU_UP_CANCELED:
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case CPU_UP_CANCELED_FROZEN:
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case CPU_DEAD:
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cpuid_device_destroy(cpu);
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break;
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}
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return notifier_from_errno(err);
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}
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static struct notifier_block cpuid_class_cpu_notifier =
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{
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.notifier_call = cpuid_class_cpu_callback,
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};
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static char *cpuid_devnode(struct device *dev, umode_t *mode)
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{
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return kasprintf(GFP_KERNEL, "cpu/%u/cpuid", MINOR(dev->devt));
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@ -160,15 +137,13 @@ static char *cpuid_devnode(struct device *dev, umode_t *mode)
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static int __init cpuid_init(void)
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{
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int i, err = 0;
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i = 0;
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int err;
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if (__register_chrdev(CPUID_MAJOR, 0, NR_CPUS,
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"cpu/cpuid", &cpuid_fops)) {
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printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n",
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CPUID_MAJOR);
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err = -EBUSY;
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goto out;
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return -EBUSY;
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}
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cpuid_class = class_create(THIS_MODULE, "cpuid");
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if (IS_ERR(cpuid_class)) {
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@ -177,42 +152,25 @@ static int __init cpuid_init(void)
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}
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cpuid_class->devnode = cpuid_devnode;
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cpu_notifier_register_begin();
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for_each_online_cpu(i) {
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err = cpuid_device_create(i);
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if (err != 0)
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goto out_class;
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}
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__register_hotcpu_notifier(&cpuid_class_cpu_notifier);
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cpu_notifier_register_done();
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err = cpuhp_setup_state(CPUHP_X86_CPUID_PREPARE, "x86/cpuid:prepare",
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cpuid_device_create, cpuid_device_destroy);
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if (err)
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goto out_class;
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err = 0;
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goto out;
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return 0;
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out_class:
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i = 0;
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for_each_online_cpu(i) {
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cpuid_device_destroy(i);
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}
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cpu_notifier_register_done();
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class_destroy(cpuid_class);
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out_chrdev:
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__unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
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out:
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return err;
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}
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static void __exit cpuid_exit(void)
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{
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int cpu = 0;
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cpu_notifier_register_begin();
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for_each_online_cpu(cpu)
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cpuid_device_destroy(cpu);
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cpuhp_remove_state(CPUHP_X86_CPUID_PREPARE);
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class_destroy(cpuid_class);
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__unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
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__unregister_hotcpu_notifier(&cpuid_class_cpu_notifier);
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cpu_notifier_register_done();
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}
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module_init(cpuid_init);
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@ -59,6 +59,7 @@ enum cpuhp_state {
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CPUHP_BLK_MQ_PREPARE,
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CPUHP_NET_FLOW_PREPARE,
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CPUHP_TOPOLOGY_PREPARE,
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CPUHP_X86_CPUID_PREPARE,
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CPUHP_TIMERS_DEAD,
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CPUHP_NOTF_ERR_INJ_PREPARE,
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CPUHP_MIPS_SOC_PREPARE,
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