Merge tag 'cpu-hotplug-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull CPU hotplug notifiers registration fixes from Rafael Wysocki:
 "The purpose of this single series of commits from Srivatsa S Bhat
  (with a small piece from Gautham R Shenoy) touching multiple
  subsystems that use CPU hotplug notifiers is to provide a way to
  register them that will not lead to deadlocks with CPU online/offline
  operations as described in the changelog of commit 93ae4f978ca7f ("CPU
  hotplug: Provide lockless versions of callback registration
  functions").

  The first three commits in the series introduce the API and document
  it and the rest simply goes through the users of CPU hotplug notifiers
  and converts them to using the new method"

* tag 'cpu-hotplug-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (52 commits)
  net/iucv/iucv.c: Fix CPU hotplug callback registration
  net/core/flow.c: Fix CPU hotplug callback registration
  mm, zswap: Fix CPU hotplug callback registration
  mm, vmstat: Fix CPU hotplug callback registration
  profile: Fix CPU hotplug callback registration
  trace, ring-buffer: Fix CPU hotplug callback registration
  xen, balloon: Fix CPU hotplug callback registration
  hwmon, via-cputemp: Fix CPU hotplug callback registration
  hwmon, coretemp: Fix CPU hotplug callback registration
  thermal, x86-pkg-temp: Fix CPU hotplug callback registration
  octeon, watchdog: Fix CPU hotplug callback registration
  oprofile, nmi-timer: Fix CPU hotplug callback registration
  intel-idle: Fix CPU hotplug callback registration
  clocksource, dummy-timer: Fix CPU hotplug callback registration
  drivers/base/topology.c: Fix CPU hotplug callback registration
  acpi-cpufreq: Fix CPU hotplug callback registration
  zsmalloc: Fix CPU hotplug callback registration
  scsi, fcoe: Fix CPU hotplug callback registration
  scsi, bnx2fc: Fix CPU hotplug callback registration
  scsi, bnx2i: Fix CPU hotplug callback registration
  ...

14 files changed, 81 insertions, 54 deletions

diff --git a/arch/x86/kernel/cpu/intel_cacheinfo.c b/arch/x86/kernel/cpu/intel_cacheinfo.c
index 0641113..a952e9c 100644
--- a/arch/x86/kernel/cpu/intel_cacheinfo.c
+++ b/arch/x86/kernel/cpu/intel_cacheinfo.c
@@ -1225,21 +1225,24 @@ static struct notifier_block cacheinfo_cpu_notifier = {
 
 static int __init cache_sysfs_init(void)
 {
-	int i;
+	int i, err = 0;
 
 	if (num_cache_leaves == 0)
 		return 0;
 
+	cpu_notifier_register_begin();
 	for_each_online_cpu(i) {
-		int err;
 		struct device *dev = get_cpu_device(i);
 
 		err = cache_add_dev(dev);
 		if (err)
-			return err;
+			goto out;
 	}
-	register_hotcpu_notifier(&cacheinfo_cpu_notifier);
-	return 0;
+	__register_hotcpu_notifier(&cacheinfo_cpu_notifier);
+
+out:
+	cpu_notifier_register_done();
+	return err;
 }
 
 device_initcall(cache_sysfs_init);
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 4d5419b..9b7734b 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -2434,14 +2434,18 @@ static __init int mcheck_init_device(void)
 	if (err)
 		return err;
 
+	cpu_notifier_register_begin();
 	for_each_online_cpu(i) {
 		err = mce_device_create(i);
-		if (err)
+		if (err) {
+			cpu_notifier_register_done();
 			return err;
+		}
 	}
 
 	register_syscore_ops(&mce_syscore_ops);
-	register_hotcpu_notifier(&mce_cpu_notifier);
+	__register_hotcpu_notifier(&mce_cpu_notifier);
+	cpu_notifier_register_done();
 
 	/* register character device /dev/mcelog */
 	misc_register(&mce_chrdev_device);
diff --git a/arch/x86/kernel/cpu/mcheck/therm_throt.c b/arch/x86/kernel/cpu/mcheck/therm_throt.c
index 3eec7de..d921b7e 100644
--- a/arch/x86/kernel/cpu/mcheck/therm_throt.c
+++ b/arch/x86/kernel/cpu/mcheck/therm_throt.c
@@ -271,9 +271,6 @@ static void thermal_throttle_remove_dev(struct device *dev)
 	sysfs_remove_group(&dev->kobj, &thermal_attr_group);
 }
 
-/* Mutex protecting device creation against CPU hotplug: */
-static DEFINE_MUTEX(therm_cpu_lock);
-
 /* Get notified when a cpu comes on/off. Be hotplug friendly. */
 static int
 thermal_throttle_cpu_callback(struct notifier_block *nfb,
@@ -289,18 +286,14 @@ thermal_throttle_cpu_callback(struct notifier_block *nfb,
 	switch (action) {
 	case CPU_UP_PREPARE:
 	case CPU_UP_PREPARE_FROZEN:
-		mutex_lock(&therm_cpu_lock);
 		err = thermal_throttle_add_dev(dev, cpu);
-		mutex_unlock(&therm_cpu_lock);
 		WARN_ON(err);
 		break;
 	case CPU_UP_CANCELED:
 	case CPU_UP_CANCELED_FROZEN:
 	case CPU_DEAD:
 	case CPU_DEAD_FROZEN:
-		mutex_lock(&therm_cpu_lock);
 		thermal_throttle_remove_dev(dev);
-		mutex_unlock(&therm_cpu_lock);
 		break;
 	}
 	return notifier_from_errno(err);
@@ -319,19 +312,16 @@ static __init int thermal_throttle_init_device(void)
 	if (!atomic_read(&therm_throt_en))
 		return 0;
 
-	register_hotcpu_notifier(&thermal_throttle_cpu_notifier);
+	cpu_notifier_register_begin();
 
-#ifdef CONFIG_HOTPLUG_CPU
-	mutex_lock(&therm_cpu_lock);
-#endif
 	/* connect live CPUs to sysfs */
 	for_each_online_cpu(cpu) {
 		err = thermal_throttle_add_dev(get_cpu_device(cpu), cpu);
 		WARN_ON(err);
 	}
-#ifdef CONFIG_HOTPLUG_CPU
-	mutex_unlock(&therm_cpu_lock);
-#endif
+
+	__register_hotcpu_notifier(&thermal_throttle_cpu_notifier);
+	cpu_notifier_register_done();
 
 	return 0;
 }
diff --git a/arch/x86/kernel/cpu/perf_event_amd_ibs.c b/arch/x86/kernel/cpu/perf_event_amd_ibs.c
index 4b8e4d3..4c36bbe 100644
--- a/arch/x86/kernel/cpu/perf_event_amd_ibs.c
+++ b/arch/x86/kernel/cpu/perf_event_amd_ibs.c
@@ -926,13 +926,13 @@ static __init int amd_ibs_init(void)
 		goto out;
 
 	perf_ibs_pm_init();
-	get_online_cpus();
+	cpu_notifier_register_begin();
 	ibs_caps = caps;
 	/* make ibs_caps visible to other cpus: */
 	smp_mb();
-	perf_cpu_notifier(perf_ibs_cpu_notifier);
 	smp_call_function(setup_APIC_ibs, NULL, 1);
-	put_online_cpus();
+	__perf_cpu_notifier(perf_ibs_cpu_notifier);
+	cpu_notifier_register_done();
 
 	ret = perf_event_ibs_init();
 out:
diff --git a/arch/x86/kernel/cpu/perf_event_amd_uncore.c b/arch/x86/kernel/cpu/perf_event_amd_uncore.c
index 754291a..3bbdf4c 100644
--- a/arch/x86/kernel/cpu/perf_event_amd_uncore.c
+++ b/arch/x86/kernel/cpu/perf_event_amd_uncore.c
@@ -531,15 +531,16 @@ static int __init amd_uncore_init(void)
 	if (ret)
 		return -ENODEV;
 
-	get_online_cpus();
+	cpu_notifier_register_begin();
+
 	/* init cpus already online before registering for hotplug notifier */
 	for_each_online_cpu(cpu) {
 		amd_uncore_cpu_up_prepare(cpu);
 		smp_call_function_single(cpu, init_cpu_already_online, NULL, 1);
 	}
 
-	register_cpu_notifier(&amd_uncore_cpu_notifier_block);
-	put_online_cpus();
+	__register_cpu_notifier(&amd_uncore_cpu_notifier_block);
+	cpu_notifier_register_done();
 
 	return 0;
 }
diff --git a/arch/x86/kernel/cpu/perf_event_intel_rapl.c b/arch/x86/kernel/cpu/perf_event_intel_rapl.c
index 5ad35ad..059218e 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_rapl.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_rapl.c
@@ -646,19 +646,20 @@ static int __init rapl_pmu_init(void)
 		/* unsupported */
 		return 0;
 	}
-	get_online_cpus();
+
+	cpu_notifier_register_begin();
 
 	for_each_online_cpu(cpu) {
 		rapl_cpu_prepare(cpu);
 		rapl_cpu_init(cpu);
 	}
 
-	perf_cpu_notifier(rapl_cpu_notifier);
+	__perf_cpu_notifier(rapl_cpu_notifier);
 
 	ret = perf_pmu_register(&rapl_pmu_class, "power", -1);
 	if (WARN_ON(ret)) {
 		pr_info("RAPL PMU detected, registration failed (%d), RAPL PMU disabled\n", ret);
-		put_online_cpus();
+		cpu_notifier_register_done();
 		return -1;
 	}
 
@@ -672,7 +673,7 @@ static int __init rapl_pmu_init(void)
 		hweight32(rapl_cntr_mask),
 		ktime_to_ms(pmu->timer_interval));
 
-	put_online_cpus();
+	cpu_notifier_register_done();
 
 	return 0;
 }
diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore.c b/arch/x86/kernel/cpu/perf_event_intel_uncore.c
index bd2253d..65bbbea 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_uncore.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.c
@@ -4244,7 +4244,7 @@ static void __init uncore_cpumask_init(void)
 	if (!cpumask_empty(&uncore_cpu_mask))
 		return;
 
-	get_online_cpus();
+	cpu_notifier_register_begin();
 
 	for_each_online_cpu(cpu) {
 		int i, phys_id = topology_physical_package_id(cpu);
@@ -4263,9 +4263,9 @@ static void __init uncore_cpumask_init(void)
 	}
 	on_each_cpu(uncore_cpu_setup, NULL, 1);
 
-	register_cpu_notifier(&uncore_cpu_nb);
+	__register_cpu_notifier(&uncore_cpu_nb);
 
-	put_online_cpus();
+	cpu_notifier_register_done();
 }
 
 
diff --git a/arch/x86/kernel/cpuid.c b/arch/x86/kernel/cpuid.c
index 7d9481c..3225ae6c 100644
--- a/arch/x86/kernel/cpuid.c
+++ b/arch/x86/kernel/cpuid.c
@@ -198,14 +198,15 @@ static int __init cpuid_init(void)
 		goto out_chrdev;
 	}
 	cpuid_class->devnode = cpuid_devnode;
-	get_online_cpus();
+
+	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);
-	put_online_cpus();
+	__register_hotcpu_notifier(&cpuid_class_cpu_notifier);
+	cpu_notifier_register_done();
 
 	err = 0;
 	goto out;
@@ -215,7 +216,7 @@ out_class:
 	for_each_online_cpu(i) {
 		cpuid_device_destroy(i);
 	}
-	put_online_cpus();
+	cpu_notifier_register_done();
 	class_destroy(cpuid_class);
 out_chrdev:
 	__unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
@@ -227,13 +228,13 @@ static void __exit cpuid_exit(void)
 {
 	int cpu = 0;
 
-	get_online_cpus();
+	cpu_notifier_register_begin();
 	for_each_online_cpu(cpu)
 		cpuid_device_destroy(cpu);
 	class_destroy(cpuid_class);
 	__unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
-	unregister_hotcpu_notifier(&cpuid_class_cpu_notifier);
-	put_online_cpus();
+	__unregister_hotcpu_notifier(&cpuid_class_cpu_notifier);
+	cpu_notifier_register_done();
 }
 
 module_init(cpuid_init);
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index 93eed15..8d80ae0 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -941,12 +941,14 @@ static __init int hpet_late_init(void)
 	if (boot_cpu_has(X86_FEATURE_ARAT))
 		return 0;
 
+	cpu_notifier_register_begin();
 	for_each_online_cpu(cpu) {
 		hpet_cpuhp_notify(NULL, CPU_ONLINE, (void *)(long)cpu);
 	}
 
 	/* This notifier should be called after workqueue is ready */
-	hotcpu_notifier(hpet_cpuhp_notify, -20);
+	__hotcpu_notifier(hpet_cpuhp_notify, -20);
+	cpu_notifier_register_done();
 
 	return 0;
 }
diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c
index 05266b5..c9603ac 100644
--- a/arch/x86/kernel/msr.c
+++ b/arch/x86/kernel/msr.c
@@ -259,14 +259,15 @@ static int __init msr_init(void)
 		goto out_chrdev;
 	}
 	msr_class->devnode = msr_devnode;
-	get_online_cpus();
+
+	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);
-	put_online_cpus();
+	__register_hotcpu_notifier(&msr_class_cpu_notifier);
+	cpu_notifier_register_done();
 
 	err = 0;
 	goto out;
@@ -275,7 +276,7 @@ out_class:
 	i = 0;
 	for_each_online_cpu(i)
 		msr_device_destroy(i);
-	put_online_cpus();
+	cpu_notifier_register_done();
 	class_destroy(msr_class);
 out_chrdev:
 	__unregister_chrdev(MSR_MAJOR, 0, NR_CPUS, "cpu/msr");
@@ -286,13 +287,14 @@ out:
 static void __exit msr_exit(void)
 {
 	int cpu = 0;
-	get_online_cpus();
+
+	cpu_notifier_register_begin();
 	for_each_online_cpu(cpu)
 		msr_device_destroy(cpu);
 	class_destroy(msr_class);
 	__unregister_chrdev(MSR_MAJOR, 0, NR_CPUS, "cpu/msr");
-	unregister_hotcpu_notifier(&msr_class_cpu_notifier);
-	put_online_cpus();
+	__unregister_hotcpu_notifier(&msr_class_cpu_notifier);
+	cpu_notifier_register_done();
 }
 
 module_init(msr_init);
diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
index 9ea28766..8b3b3eb 100644
--- a/arch/x86/kernel/vsyscall_64.c
+++ b/arch/x86/kernel/vsyscall_64.c
@@ -348,9 +348,13 @@ static int __init vsyscall_init(void)
 {
 	BUG_ON(VSYSCALL_ADDR(0) != __fix_to_virt(VSYSCALL_FIRST_PAGE));
 
+	cpu_notifier_register_begin();
+
 	on_each_cpu(cpu_vsyscall_init, NULL, 1);
 	/* notifier priority > KVM */
-	hotcpu_notifier(cpu_vsyscall_notifier, 30);
+	__hotcpu_notifier(cpu_vsyscall_notifier, 30);
+
+	cpu_notifier_register_done();
 
 	return 0;
 }
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d1c55f8..9d1b5cd 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5422,7 +5422,8 @@ static void kvm_timer_init(void)
 	int cpu;
 
 	max_tsc_khz = tsc_khz;
-	register_hotcpu_notifier(&kvmclock_cpu_notifier_block);
+
+	cpu_notifier_register_begin();
 	if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) {
 #ifdef CONFIG_CPU_FREQ
 		struct cpufreq_policy policy;
@@ -5439,6 +5440,10 @@ static void kvm_timer_init(void)
 	pr_debug("kvm: max_tsc_khz = %ld\n", max_tsc_khz);
 	for_each_online_cpu(cpu)
 		smp_call_function_single(cpu, tsc_khz_changed, NULL, 1);
+
+	__register_hotcpu_notifier(&kvmclock_cpu_notifier_block);
+	cpu_notifier_register_done();
+
 }
 
 static DEFINE_PER_CPU(struct kvm_vcpu *, current_vcpu);
diff --git a/arch/x86/oprofile/nmi_int.c b/arch/x86/oprofile/nmi_int.c
index 6890d84..379e8bd 100644
--- a/arch/x86/oprofile/nmi_int.c
+++ b/arch/x86/oprofile/nmi_int.c
@@ -494,14 +494,19 @@ static int nmi_setup(void)
 	if (err)
 		goto fail;
 
+	cpu_notifier_register_begin();
+
+	/* Use get/put_online_cpus() to protect 'nmi_enabled' */
 	get_online_cpus();
-	register_cpu_notifier(&oprofile_cpu_nb);
 	nmi_enabled = 1;
 	/* make nmi_enabled visible to the nmi handler: */
 	smp_mb();
 	on_each_cpu(nmi_cpu_setup, NULL, 1);
+	__register_cpu_notifier(&oprofile_cpu_nb);
 	put_online_cpus();
 
+	cpu_notifier_register_done();
+
 	return 0;
 fail:
 	free_msrs();
@@ -512,12 +517,18 @@ static void nmi_shutdown(void)
 {
 	struct op_msrs *msrs;
 
+	cpu_notifier_register_begin();
+
+	/* Use get/put_online_cpus() to protect 'nmi_enabled' & 'ctr_running' */
 	get_online_cpus();
-	unregister_cpu_notifier(&oprofile_cpu_nb);
 	on_each_cpu(nmi_cpu_shutdown, NULL, 1);
 	nmi_enabled = 0;
 	ctr_running = 0;
+	__unregister_cpu_notifier(&oprofile_cpu_nb);
 	put_online_cpus();
+
+	cpu_notifier_register_done();
+
 	/* make variables visible to the nmi handler: */
 	smp_mb();
 	unregister_nmi_handler(NMI_LOCAL, "oprofile");
diff --git a/arch/x86/pci/amd_bus.c b/arch/x86/pci/amd_bus.c
index a313a7f..e88f4c5 100644
--- a/arch/x86/pci/amd_bus.c
+++ b/arch/x86/pci/amd_bus.c
@@ -370,10 +370,13 @@ static int __init pci_io_ecs_init(void)
 	if (early_pci_allowed())
 		pci_enable_pci_io_ecs();
 
-	register_cpu_notifier(&amd_cpu_notifier);
+	cpu_notifier_register_begin();
 	for_each_online_cpu(cpu)
 		amd_cpu_notify(&amd_cpu_notifier, (unsigned long)CPU_ONLINE,
 			       (void *)(long)cpu);
+	__register_cpu_notifier(&amd_cpu_notifier);
+	cpu_notifier_register_done();
+
 	pci_probe |= PCI_HAS_IO_ECS;
 
 	return 0;