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author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2016-11-17 21:35:24 +0300 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2016-11-23 01:34:39 +0300 |
commit | 8fba38c937cd585bcf562fda8db3decb25509506 (patch) | |
tree | 973a8b90fee900ee9aa03f7401a0cf5d9472ce5e /arch/x86/kernel/msr.c | |
parent | ee92be9b0d7ad34cb58b61d5c0933d2e5ff7c31d (diff) | |
download | linux-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.c | 69 |
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>"); |