Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull smp hotplug updates from Thomas Gleixner:
 "This is the final round of converting the notifier mess to the state
  machine. The removal of the notifiers and the related infrastructure
  will happen around rc1, as there are conversions outstanding in other
  trees.

  The whole exercise removed about 2000 lines of code in total and in
  course of the conversion several dozen bugs got fixed. The new
  mechanism allows to test almost every hotplug step standalone, so
  usage sites can exercise all transitions extensively.

  There is more room for improvement, like integrating all the
  pointlessly different architecture mechanisms of synchronizing,
  setting cpus online etc into the core code"

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (60 commits)
  tracing/rb: Init the CPU mask on allocation
  soc/fsl/qbman: Convert to hotplug state machine
  soc/fsl/qbman: Convert to hotplug state machine
  zram: Convert to hotplug state machine
  KVM/PPC/Book3S HV: Convert to hotplug state machine
  arm64/cpuinfo: Convert to hotplug state machine
  arm64/cpuinfo: Make hotplug notifier symmetric
  mm/compaction: Convert to hotplug state machine
  iommu/vt-d: Convert to hotplug state machine
  mm/zswap: Convert pool to hotplug state machine
  mm/zswap: Convert dst-mem to hotplug state machine
  mm/zsmalloc: Convert to hotplug state machine
  mm/vmstat: Convert to hotplug state machine
  mm/vmstat: Avoid on each online CPU loops
  mm/vmstat: Drop get_online_cpus() from init_cpu_node_state/vmstat_cpu_dead()
  tracing/rb: Convert to hotplug state machine
  oprofile/nmi timer: Convert to hotplug state machine
  net/iucv: Use explicit clean up labels in iucv_init()
  x86/pci/amd-bus: Convert to hotplug state machine
  x86/oprofile/nmi: Convert to hotplug state machine
  ...

arch/arm/common/bL_switcher.c

@@ -757,19 +757,18 @@ EXPORT_SYMBOL_GPL(bL_switcher_put_enabled);
  * while the switcher is active.
  * We're just not ready to deal with that given the trickery involved.
  */
-static int bL_switcher_hotplug_callback(struct notifier_block *nfb,
-					unsigned long action, void *hcpu)
+static int bL_switcher_cpu_pre(unsigned int cpu)
 {
-	if (bL_switcher_active) {
-		int pairing = bL_switcher_cpu_pairing[(unsigned long)hcpu];
-		switch (action & 0xf) {
-		case CPU_UP_PREPARE:
-		case CPU_DOWN_PREPARE:
-			if (pairing == -1)
-				return NOTIFY_BAD;
-		}
-	}
-	return NOTIFY_DONE;
+	int pairing;
+
+	if (!bL_switcher_active)
+		return 0;
+
+	pairing = bL_switcher_cpu_pairing[cpu];
+
+	if (pairing == -1)
+		return -EINVAL;
+	return 0;
 }
 
 static bool no_bL_switcher;
@@ -782,8 +781,15 @@ static int __init bL_switcher_init(void)
 	if (!mcpm_is_available())
 		return -ENODEV;
 
-	cpu_notifier(bL_switcher_hotplug_callback, 0);
-
+	cpuhp_setup_state_nocalls(CPUHP_ARM_BL_PREPARE, "arm/bl:prepare",
+				  bL_switcher_cpu_pre, NULL);
+	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "arm/bl:predown",
+					NULL, bL_switcher_cpu_pre);
+	if (ret < 0) {
+		cpuhp_remove_state_nocalls(CPUHP_ARM_BL_PREPARE);
+		pr_err("bL_switcher: Failed to allocate a hotplug state\n");
+		return ret;
+	}
 	if (!no_bL_switcher) {
 		ret = bL_switcher_enable();
 		if (ret)

arch/arm/kernel/hw_breakpoint.c

@@ -925,9 +925,9 @@ static bool core_has_os_save_restore(void)
 	}
 }
 
-static void reset_ctrl_regs(void *unused)
+static void reset_ctrl_regs(unsigned int cpu)
 {
-	int i, raw_num_brps, err = 0, cpu = smp_processor_id();
+	int i, raw_num_brps, err = 0;
 	u32 val;
 
 	/*
@@ -1020,25 +1020,20 @@ out_mdbgen:
 		cpumask_or(&debug_err_mask, &debug_err_mask, cpumask_of(cpu));
 }
 
-static int dbg_reset_notify(struct notifier_block *self,
-				      unsigned long action, void *cpu)
+static int dbg_reset_online(unsigned int cpu)
 {
-	if ((action & ~CPU_TASKS_FROZEN) == CPU_ONLINE)
-		smp_call_function_single((int)cpu, reset_ctrl_regs, NULL, 1);
-
-	return NOTIFY_OK;
+	local_irq_disable();
+	reset_ctrl_regs(cpu);
+	local_irq_enable();
+	return 0;
 }
 
-static struct notifier_block dbg_reset_nb = {
-	.notifier_call = dbg_reset_notify,
-};
-
 #ifdef CONFIG_CPU_PM
 static int dbg_cpu_pm_notify(struct notifier_block *self, unsigned long action,
 			     void *v)
 {
 	if (action == CPU_PM_EXIT)
-		reset_ctrl_regs(NULL);
+		reset_ctrl_regs(smp_processor_id());
 
 	return NOTIFY_OK;
 }
@@ -1059,6 +1054,8 @@ static inline void pm_init(void)
 
 static int __init arch_hw_breakpoint_init(void)
 {
+	int ret;
+
 	debug_arch = get_debug_arch();
 
 	if (!debug_arch_supported()) {
@@ -1072,25 +1069,28 @@ static int __init arch_hw_breakpoint_init(void)
 	core_num_brps = get_num_brps();
 	core_num_wrps = get_num_wrps();
 
-	cpu_notifier_register_begin();
-
 	/*
 	 * We need to tread carefully here because DBGSWENABLE may be
 	 * driven low on this core and there isn't an architected way to
 	 * determine that.
 	 */
+	get_online_cpus();
 	register_undef_hook(&debug_reg_hook);
 
 	/*
-	 * Reset the breakpoint resources. We assume that a halting
-	 * debugger will leave the world in a nice state for us.
+	 * Register CPU notifier which resets the breakpoint resources. We
+	 * assume that a halting debugger will leave the world in a nice state
+	 * for us.
 	 */
-	on_each_cpu(reset_ctrl_regs, NULL, 1);
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "arm/hw_breakpoint:online",
+				dbg_reset_online, NULL);
 	unregister_undef_hook(&debug_reg_hook);
-	if (!cpumask_empty(&debug_err_mask)) {
+	if (WARN_ON(ret < 0) || !cpumask_empty(&debug_err_mask)) {
 		core_num_brps = 0;
 		core_num_wrps = 0;
-		cpu_notifier_register_done();
+		if (ret > 0)
+			cpuhp_remove_state_nocalls(ret);
+		put_online_cpus();
 		return 0;
 	}
 
@@ -1108,12 +1108,9 @@ static int __init arch_hw_breakpoint_init(void)
 			TRAP_HWBKPT, "watchpoint debug exception");
 	hook_ifault_code(FAULT_CODE_DEBUG, hw_breakpoint_pending, SIGTRAP,
 			TRAP_HWBKPT, "breakpoint debug exception");
+	put_online_cpus();
 
-	/* Register hotplug and PM notifiers. */
-	__register_cpu_notifier(&dbg_reset_nb);
-
-	cpu_notifier_register_done();
-
+	/* Register PM notifiers. */
 	pm_init();
 	return 0;
 }

arch/arm64/kernel/cpuinfo.c

@@ -227,7 +227,7 @@ static struct attribute_group cpuregs_attr_group = {
 	.name = "identification"
 };
 
-static int cpuid_add_regs(int cpu)
+static int cpuid_cpu_online(unsigned int cpu)
 {
 	int rc;
 	struct device *dev;
@@ -248,7 +248,7 @@ out:
 	return rc;
 }
 
-static int cpuid_remove_regs(int cpu)
+static int cpuid_cpu_offline(unsigned int cpu)
 {
 	struct device *dev;
 	struct cpuinfo_arm64 *info = &per_cpu(cpu_data, cpu);
@@ -264,40 +264,22 @@ static int cpuid_remove_regs(int cpu)
 	return 0;
 }
 
-static int cpuid_callback(struct notifier_block *nb,
-			 unsigned long action, void *hcpu)
-{
-	int rc = 0;
-	unsigned long cpu = (unsigned long)hcpu;
-
-	switch (action & ~CPU_TASKS_FROZEN) {
-	case CPU_ONLINE:
-		rc = cpuid_add_regs(cpu);
-		break;
-	case CPU_DEAD:
-		rc = cpuid_remove_regs(cpu);
-		break;
-	}
-
-	return notifier_from_errno(rc);
-}
-
 static int __init cpuinfo_regs_init(void)
 {
-	int cpu;
-
-	cpu_notifier_register_begin();
+	int cpu, ret;
 
 	for_each_possible_cpu(cpu) {
 		struct cpuinfo_arm64 *info = &per_cpu(cpu_data, cpu);
 
 		kobject_init(&info->kobj, &cpuregs_kobj_type);
-		if (cpu_online(cpu))
-			cpuid_add_regs(cpu);
 	}
-	__hotcpu_notifier(cpuid_callback, 0);
 
-	cpu_notifier_register_done();
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "arm64/cpuinfo:online",
+				cpuid_cpu_online, cpuid_cpu_offline);
+	if (ret < 0) {
+		pr_err("cpuinfo: failed to register hotplug callbacks.\n");
+		return ret;
+	}
 	return 0;
 }
 static void cpuinfo_detect_icache_policy(struct cpuinfo_arm64 *info)

arch/ia64/kernel/err_inject.c

@@ -224,85 +224,45 @@ static struct attribute_group err_inject_attr_group = {
 	.name = "err_inject"
 };
 /* Add/Remove err_inject interface for CPU device */
-static int err_inject_add_dev(struct device *sys_dev)
+static int err_inject_add_dev(unsigned int cpu)
 {
+	struct device *sys_dev = get_cpu_device(cpu);
+
 	return sysfs_create_group(&sys_dev->kobj, &err_inject_attr_group);
 }
 
-static int err_inject_remove_dev(struct device *sys_dev)
+static int err_inject_remove_dev(unsigned int cpu)
 {
+	struct device *sys_dev = get_cpu_device(cpu);
+
 	sysfs_remove_group(&sys_dev->kobj, &err_inject_attr_group);
 	return 0;
 }
-static int err_inject_cpu_callback(struct notifier_block *nfb,
-		unsigned long action, void *hcpu)
-{
-	unsigned int cpu = (unsigned long)hcpu;
-	struct device *sys_dev;
-
-	sys_dev = get_cpu_device(cpu);
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		err_inject_add_dev(sys_dev);
-		break;
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		err_inject_remove_dev(sys_dev);
-		break;
-	}
-
-	return NOTIFY_OK;
-}
 
-static struct notifier_block err_inject_cpu_notifier =
-{
-	.notifier_call = err_inject_cpu_callback,
-};
+static enum cpuhp_state hp_online;
 
-static int __init
-err_inject_init(void)
+static int __init err_inject_init(void)
 {
-	int i;
-
+	int ret;
 #ifdef ERR_INJ_DEBUG
 	printk(KERN_INFO "Enter error injection driver.\n");
 #endif
 
-	cpu_notifier_register_begin();
-
-	for_each_online_cpu(i) {
-		err_inject_cpu_callback(&err_inject_cpu_notifier, CPU_ONLINE,
-				(void *)(long)i);
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "ia64/err_inj:online",
+				err_inject_add_dev, err_inject_remove_dev);
+	if (ret >= 0) {
+		hp_online = ret;
+		ret = 0;
 	}
-
-	__register_hotcpu_notifier(&err_inject_cpu_notifier);
-
-	cpu_notifier_register_done();
-
-	return 0;
+	return ret;
 }
 
-static void __exit
-err_inject_exit(void)
+static void __exit err_inject_exit(void)
 {
-	int i;
-	struct device *sys_dev;
-
 #ifdef ERR_INJ_DEBUG
 	printk(KERN_INFO "Exit error injection driver.\n");
 #endif
-
-	cpu_notifier_register_begin();
-
-	for_each_online_cpu(i) {
-		sys_dev = get_cpu_device(i);
-		sysfs_remove_group(&sys_dev->kobj, &err_inject_attr_group);
-	}
-
-	__unregister_hotcpu_notifier(&err_inject_cpu_notifier);
-
-	cpu_notifier_register_done();
+	cpuhp_remove_state(hp_online);
 }
 
 module_init(err_inject_init);

arch/ia64/kernel/palinfo.c

@@ -932,8 +932,7 @@ static const struct file_operations proc_palinfo_fops = {
 	.release	= single_release,
 };
 
-static void
-create_palinfo_proc_entries(unsigned int cpu)
+static int palinfo_add_proc(unsigned int cpu)
 {
 	pal_func_cpu_u_t f;
 	struct proc_dir_entry *cpu_dir;
@@ -943,7 +942,7 @@ create_palinfo_proc_entries(unsigned int cpu)
 
 	cpu_dir = proc_mkdir(cpustr, palinfo_dir);
 	if (!cpu_dir)
-		return;
+		return -EINVAL;
 
 	f.req_cpu = cpu;
 
@@ -952,42 +951,21 @@ create_palinfo_proc_entries(unsigned int cpu)
 		proc_create_data(palinfo_entries[j].name, 0, cpu_dir,
 				 &proc_palinfo_fops, (void *)f.value);
 	}
+	return 0;
 }
 
-static void
-remove_palinfo_proc_entries(unsigned int hcpu)
+static int palinfo_del_proc(unsigned int hcpu)
 {
 	char cpustr[3+4+1];	/* cpu numbers are up to 4095 on itanic */
+
 	sprintf(cpustr, "cpu%d", hcpu);
 	remove_proc_subtree(cpustr, palinfo_dir);
+	return 0;
 }
 
-static int palinfo_cpu_callback(struct notifier_block *nfb,
-					unsigned long action, void *hcpu)
-{
-	unsigned int hotcpu = (unsigned long)hcpu;
-
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		create_palinfo_proc_entries(hotcpu);
-		break;
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		remove_palinfo_proc_entries(hotcpu);
-		break;
-	}
-	return NOTIFY_OK;
-}
-
-static struct notifier_block __refdata palinfo_cpu_notifier =
-{
-	.notifier_call = palinfo_cpu_callback,
-	.priority = 0,
-};
+static enum cpuhp_state hp_online;
 
-static int __init
-palinfo_init(void)
+static int __init palinfo_init(void)
 {
 	int i = 0;
 
@@ -996,25 +974,19 @@ palinfo_init(void)
 	if (!palinfo_dir)
 		return -ENOMEM;
 
-	cpu_notifier_register_begin();
-
-	/* Create palinfo dirs in /proc for all online cpus */
-	for_each_online_cpu(i) {
-		create_palinfo_proc_entries(i);
+	i = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "ia64/palinfo:online",
+			      palinfo_add_proc, palinfo_del_proc);
+	if (i < 0) {
+		remove_proc_subtree("pal", NULL);
+		return i;
 	}
-
-	/* Register for future delivery via notify registration */
-	__register_hotcpu_notifier(&palinfo_cpu_notifier);
-
-	cpu_notifier_register_done();
-
+	hp_online = i;
 	return 0;
 }
 
-static void __exit
-palinfo_exit(void)
+static void __exit palinfo_exit(void)
 {
-	unregister_hotcpu_notifier(&palinfo_cpu_notifier);
+	cpuhp_remove_state(hp_online);
 	remove_proc_subtree("pal", NULL);
 }
 

arch/ia64/kernel/salinfo.c

@@ -550,52 +550,40 @@ static const struct file_operations salinfo_data_fops = {
 	.llseek  = default_llseek,
 };
 
-static int
-salinfo_cpu_callback(struct notifier_block *nb, unsigned long action, void *hcpu)
+static int salinfo_cpu_online(unsigned int cpu)
 {
-	unsigned int i, cpu = (unsigned long)hcpu;
-	unsigned long flags;
+	unsigned int i, end = ARRAY_SIZE(salinfo_data);
 	struct salinfo_data *data;
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		spin_lock_irqsave(&data_saved_lock, flags);
-		for (i = 0, data = salinfo_data;
-		     i < ARRAY_SIZE(salinfo_data);
-		     ++i, ++data) {
-			cpumask_set_cpu(cpu, &data->cpu_event);
-			wake_up_interruptible(&data->read_wait);
-		}
-		spin_unlock_irqrestore(&data_saved_lock, flags);
-		break;
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		spin_lock_irqsave(&data_saved_lock, flags);
-		for (i = 0, data = salinfo_data;
-		     i < ARRAY_SIZE(salinfo_data);
-		     ++i, ++data) {
-			struct salinfo_data_saved *data_saved;
-			int j;
-			for (j = ARRAY_SIZE(data->data_saved) - 1, data_saved = data->data_saved + j;
-			     j >= 0;
-			     --j, --data_saved) {
-				if (data_saved->buffer && data_saved->cpu == cpu) {
-					shift1_data_saved(data, j);
-				}
-			}
-			cpumask_clear_cpu(cpu, &data->cpu_event);
-		}
-		spin_unlock_irqrestore(&data_saved_lock, flags);
-		break;
+
+	spin_lock_irq(&data_saved_lock);
+	for (i = 0, data = salinfo_data; i < end; ++i, ++data) {
+		cpumask_set_cpu(cpu, &data->cpu_event);
+		wake_up_interruptible(&data->read_wait);
 	}
-	return NOTIFY_OK;
+	spin_unlock_irq(&data_saved_lock);
+	return 0;
 }
 
-static struct notifier_block salinfo_cpu_notifier =
+static int salinfo_cpu_pre_down(unsigned int cpu)
 {
-	.notifier_call = salinfo_cpu_callback,
-	.priority = 0,
-};
+	unsigned int i, end = ARRAY_SIZE(salinfo_data);
+	struct salinfo_data *data;
+
+	spin_lock_irq(&data_saved_lock);
+	for (i = 0, data = salinfo_data; i < end; ++i, ++data) {
+		struct salinfo_data_saved *data_saved;
+		int j = ARRAY_SIZE(data->data_saved) - 1;
+
+		for (data_saved = data->data_saved + j; j >= 0;
+		     --j, --data_saved) {
+			if (data_saved->buffer && data_saved->cpu == cpu)
+				shift1_data_saved(data, j);
+		}
+		cpumask_clear_cpu(cpu, &data->cpu_event);
+	}
+	spin_unlock_irq(&data_saved_lock);
+	return 0;
+}
 
 static int __init
 salinfo_init(void)
@@ -604,7 +592,7 @@ salinfo_init(void)
 	struct proc_dir_entry **sdir = salinfo_proc_entries; /* keeps track of every entry */
 	struct proc_dir_entry *dir, *entry;
 	struct salinfo_data *data;
-	int i, j;
+	int i;
 
 	salinfo_dir = proc_mkdir("sal", NULL);
 	if (!salinfo_dir)
@@ -617,8 +605,6 @@ salinfo_init(void)
 					   (void *)salinfo_entries[i].feature);
 	}
 
-	cpu_notifier_register_begin();
-
 	for (i = 0; i < ARRAY_SIZE(salinfo_log_name); i++) {
 		data = salinfo_data + i;
 		data->type = i;
@@ -639,10 +625,6 @@ salinfo_init(void)
 			continue;
 		*sdir++ = entry;
 
-		/* we missed any events before now */
-		for_each_online_cpu(j)
-			cpumask_set_cpu(j, &data->cpu_event);
-
 		*sdir++ = dir;
 	}
 
@@ -653,10 +635,9 @@ salinfo_init(void)
 	salinfo_timer.function = &salinfo_timeout;
 	add_timer(&salinfo_timer);
 
-	__register_hotcpu_notifier(&salinfo_cpu_notifier);
-
-	cpu_notifier_register_done();
-
+	i = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "ia64/salinfo:online",
+			      salinfo_cpu_online, salinfo_cpu_pre_down);
+	WARN_ON(i < 0);
 	return 0;
 }
 

arch/ia64/kernel/topology.c

@@ -349,9 +349,9 @@ static int cpu_cache_sysfs_init(unsigned int cpu)
 }
 
 /* Add cache interface for CPU device */
-static int cache_add_dev(struct device *sys_dev)
+static int cache_add_dev(unsigned int cpu)
 {
-	unsigned int cpu = sys_dev->id;
+	struct device *sys_dev = get_cpu_device(cpu);
 	unsigned long i, j;
 	struct cache_info *this_object;
 	int retval = 0;
@@ -399,9 +399,8 @@ static int cache_add_dev(struct device *sys_dev)
 }
 
 /* Remove cache interface for CPU device */
-static int cache_remove_dev(struct device *sys_dev)
+static int cache_remove_dev(unsigned int cpu)
 {
-	unsigned int cpu = sys_dev->id;
 	unsigned long i;
 
 	for (i = 0; i < all_cpu_cache_info[cpu].num_cache_leaves; i++)
@@ -419,52 +418,13 @@ static int cache_remove_dev(struct device *sys_dev)
 	return 0;
 }
 
-/*
- * When a cpu is hot-plugged, do a check and initiate
- * cache kobject if necessary
- */
-static int cache_cpu_callback(struct notifier_block *nfb,
-		unsigned long action, void *hcpu)
-{
-	unsigned int cpu = (unsigned long)hcpu;
-	struct device *sys_dev;
-
-	sys_dev = get_cpu_device(cpu);
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		cache_add_dev(sys_dev);
-		break;
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		cache_remove_dev(sys_dev);
-		break;
-	}
-	return NOTIFY_OK;
-}
-
-static struct notifier_block cache_cpu_notifier =
-{
-	.notifier_call = cache_cpu_callback
-};
-
 static int __init cache_sysfs_init(void)
 {
-	int i;
-
-	cpu_notifier_register_begin();
-
-	for_each_online_cpu(i) {
-		struct device *sys_dev = get_cpu_device((unsigned int)i);
-		cache_add_dev(sys_dev);
-	}
-
-	__register_hotcpu_notifier(&cache_cpu_notifier);
-
-	cpu_notifier_register_done();
+	int ret;
 
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "ia64/topology:online",
+				cache_add_dev, cache_remove_dev);
+	WARN_ON(ret < 0);
 	return 0;
 }
-
 device_initcall(cache_sysfs_init);
-

arch/powerpc/kernel/sysfs.c

@@ -703,7 +703,7 @@ static struct device_attribute pa6t_attrs[] = {
 #endif /* HAS_PPC_PMC_PA6T */
 #endif /* HAS_PPC_PMC_CLASSIC */
 
-static void register_cpu_online(unsigned int cpu)
+static int register_cpu_online(unsigned int cpu)
 {
 	struct cpu *c = &per_cpu(cpu_devices, cpu);
 	struct device *s = &c->dev;
@@ -782,11 +782,12 @@ static void register_cpu_online(unsigned int cpu)
 	}
 #endif
 	cacheinfo_cpu_online(cpu);
+	return 0;
 }
 
-#ifdef CONFIG_HOTPLUG_CPU
-static void unregister_cpu_online(unsigned int cpu)
+static int unregister_cpu_online(unsigned int cpu)
 {
+#ifdef CONFIG_HOTPLUG_CPU
 	struct cpu *c = &per_cpu(cpu_devices, cpu);
 	struct device *s = &c->dev;
 	struct device_attribute *attrs, *pmc_attrs;
@@ -863,6 +864,8 @@ static void unregister_cpu_online(unsigned int cpu)
 	}
 #endif
 	cacheinfo_cpu_offline(cpu);
+#endif /* CONFIG_HOTPLUG_CPU */
+	return 0;
 }
 
 #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
@@ -883,32 +886,6 @@ ssize_t arch_cpu_release(const char *buf, size_t count)
 }
 #endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
 
-#endif /* CONFIG_HOTPLUG_CPU */
-
-static int sysfs_cpu_notify(struct notifier_block *self,
-				      unsigned long action, void *hcpu)
-{
-	unsigned int cpu = (unsigned int)(long)hcpu;
-
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		register_cpu_online(cpu);
-		break;
-#ifdef CONFIG_HOTPLUG_CPU
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		unregister_cpu_online(cpu);
-		break;
-#endif
-	}
-	return NOTIFY_OK;
-}
-
-static struct notifier_block sysfs_cpu_nb = {
-	.notifier_call	= sysfs_cpu_notify,
-};
-
 static DEFINE_MUTEX(cpu_mutex);
 
 int cpu_add_dev_attr(struct device_attribute *attr)
@@ -1023,12 +1000,10 @@ static DEVICE_ATTR(physical_id, 0444, show_physical_id, NULL);
 
 static int __init topology_init(void)
 {
-	int cpu;
+	int cpu, r;
 
 	register_nodes();
 
-	cpu_notifier_register_begin();
-
 	for_each_possible_cpu(cpu) {
 		struct cpu *c = &per_cpu(cpu_devices, cpu);
 
@@ -1047,15 +1022,10 @@ static int __init topology_init(void)
 
 			device_create_file(&c->dev, &dev_attr_physical_id);
 		}
-
-		if (cpu_online(cpu))
-			register_cpu_online(cpu);
 	}
-
-	__register_cpu_notifier(&sysfs_cpu_nb);
-
-	cpu_notifier_register_done();
-
+	r = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "powerpc/topology:online",
+			      register_cpu_online, unregister_cpu_online);
+	WARN_ON(r < 0);
 #ifdef CONFIG_PPC64
 	sysfs_create_dscr_default();
 #endif /* CONFIG_PPC64 */

arch/powerpc/kvm/book3s_hv.c

@@ -2254,12 +2254,12 @@ static void post_guest_process(struct kvmppc_vcore *vc, bool is_master)
  * enter the guest. Only do this if it is the primary thread of the
  * core (not if a subcore) that is entering the guest.
  */
-static inline void kvmppc_clear_host_core(int cpu)
+static inline int kvmppc_clear_host_core(unsigned int cpu)
 {
 	int core;
 
 	if (!kvmppc_host_rm_ops_hv || cpu_thread_in_core(cpu))
-		return;
+		return 0;
 	/*
 	 * Memory barrier can be omitted here as we will do a smp_wmb()
 	 * later in kvmppc_start_thread and we need ensure that state is
@@ -2267,6 +2267,7 @@ static inline void kvmppc_clear_host_core(int cpu)
 	 */
 	core = cpu >> threads_shift;
 	kvmppc_host_rm_ops_hv->rm_core[core].rm_state.in_host = 0;
+	return 0;
 }
 
 /*
@@ -2274,12 +2275,12 @@ static inline void kvmppc_clear_host_core(int cpu)
  * Only need to do this if it is the primary thread of the core that is
  * exiting.
  */
-static inline void kvmppc_set_host_core(int cpu)
+static inline int kvmppc_set_host_core(unsigned int cpu)
 {
 	int core;
 
 	if (!kvmppc_host_rm_ops_hv || cpu_thread_in_core(cpu))
-		return;
+		return 0;
 
 	/*
 	 * Memory barrier can be omitted here because we do a spin_unlock
@@ -2287,6 +2288,7 @@ static inline void kvmppc_set_host_core(int cpu)
 	 */
 	core = cpu >> threads_shift;
 	kvmppc_host_rm_ops_hv->rm_core[core].rm_state.in_host = 1;
+	return 0;
 }
 
 /*
@@ -3094,36 +3096,6 @@ static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu)
 }
 
 #ifdef CONFIG_KVM_XICS
-static int kvmppc_cpu_notify(struct notifier_block *self, unsigned long action,
-			void *hcpu)
-{
-	unsigned long cpu = (long)hcpu;
-
-	switch (action) {
-	case CPU_UP_PREPARE:
-	case CPU_UP_PREPARE_FROZEN:
-		kvmppc_set_host_core(cpu);
-		break;
-
-#ifdef CONFIG_HOTPLUG_CPU
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-	case CPU_UP_CANCELED:
-	case CPU_UP_CANCELED_FROZEN:
-		kvmppc_clear_host_core(cpu);
-		break;
-#endif
-	default:
-		break;
-	}
-
-	return NOTIFY_OK;
-}
-
-static struct notifier_block kvmppc_cpu_notifier = {
-	    .notifier_call = kvmppc_cpu_notify,
-};
-
 /*
  * Allocate a per-core structure for managing state about which cores are
  * running in the host versus the guest and for exchanging data between
@@ -3185,15 +3157,17 @@ void kvmppc_alloc_host_rm_ops(void)
 		return;
 	}
 
-	register_cpu_notifier(&kvmppc_cpu_notifier);
-
+	cpuhp_setup_state_nocalls(CPUHP_KVM_PPC_BOOK3S_PREPARE,
+				  "ppc/kvm_book3s:prepare",
+				  kvmppc_set_host_core,
+				  kvmppc_clear_host_core);
 	put_online_cpus();
 }
 
 void kvmppc_free_host_rm_ops(void)
 {
 	if (kvmppc_host_rm_ops_hv) {
-		unregister_cpu_notifier(&kvmppc_cpu_notifier);
+		cpuhp_remove_state_nocalls(CPUHP_KVM_PPC_BOOK3S_PREPARE);
 		kfree(kvmppc_host_rm_ops_hv->rm_core);
 		kfree(kvmppc_host_rm_ops_hv);
 		kvmppc_host_rm_ops_hv = NULL;

arch/s390/kernel/smp.c

@@ -1052,22 +1052,18 @@ static struct attribute_group cpu_online_attr_group = {
 	.attrs = cpu_online_attrs,
 };
 
-static int smp_cpu_notify(struct notifier_block *self, unsigned long action,
-			  void *hcpu)
+static int smp_cpu_online(unsigned int cpu)
 {
-	unsigned int cpu = (unsigned int)(long)hcpu;
 	struct device *s = &per_cpu(cpu_device, cpu)->dev;
-	int err = 0;
 
-	switch (action & ~CPU_TASKS_FROZEN) {
-	case CPU_ONLINE:
-		err = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
-		break;
-	case CPU_DEAD:
-		sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
-		break;
-	}
-	return notifier_from_errno(err);
+	return sysfs_create_group(&s->kobj, &cpu_online_attr_group);
+}
+static int smp_cpu_pre_down(unsigned int cpu)
+{
+	struct device *s = &per_cpu(cpu_device, cpu)->dev;
+
+	sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
+	return 0;
 }
 
 static int smp_add_present_cpu(int cpu)
@@ -1088,20 +1084,12 @@ static int smp_add_present_cpu(int cpu)
 	rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
 	if (rc)
 		goto out_cpu;
-	if (cpu_online(cpu)) {
-		rc = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
-		if (rc)
-			goto out_online;
-	}
 	rc = topology_cpu_init(c);
 	if (rc)
 		goto out_topology;
 	return 0;
 
 out_topology:
-	if (cpu_online(cpu))
-		sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
-out_online:
 	sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
 out_cpu:
 #ifdef CONFIG_HOTPLUG_CPU
@@ -1154,17 +1142,15 @@ static int __init s390_smp_init(void)
 	if (rc)
 		return rc;
 #endif
-	cpu_notifier_register_begin();
 	for_each_present_cpu(cpu) {
 		rc = smp_add_present_cpu(cpu);
 		if (rc)
 			goto out;
 	}
 
-	__hotcpu_notifier(smp_cpu_notify, 0);
-
+	rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "s390/smp:online",
+			       smp_cpu_online, smp_cpu_pre_down);
 out:
-	cpu_notifier_register_done();
 	return rc;
 }
 subsys_initcall(s390_smp_init);

arch/sparc/kernel/sysfs.c

@@ -221,7 +221,7 @@ static struct device_attribute cpu_core_attrs[] = {
 
 static DEFINE_PER_CPU(struct cpu, cpu_devices);
 
-static void register_cpu_online(unsigned int cpu)
+static int register_cpu_online(unsigned int cpu)
 {
 	struct cpu *c = &per_cpu(cpu_devices, cpu);
 	struct device *s = &c->dev;
@@ -231,11 +231,12 @@ static void register_cpu_online(unsigned int cpu)
 		device_create_file(s, &cpu_core_attrs[i]);
 
 	register_mmu_stats(s);
+	return 0;
 }
 
-#ifdef CONFIG_HOTPLUG_CPU
-static void unregister_cpu_online(unsigned int cpu)
+static int unregister_cpu_online(unsigned int cpu)
 {
+#ifdef CONFIG_HOTPLUG_CPU
 	struct cpu *c = &per_cpu(cpu_devices, cpu);
 	struct device *s = &c->dev;
 	int i;
@@ -243,33 +244,10 @@ static void unregister_cpu_online(unsigned int cpu)
 	unregister_mmu_stats(s);
 	for (i = 0; i < ARRAY_SIZE(cpu_core_attrs); i++)
 		device_remove_file(s, &cpu_core_attrs[i]);
-}
-#endif
-
-static int sysfs_cpu_notify(struct notifier_block *self,
-				      unsigned long action, void *hcpu)
-{
-	unsigned int cpu = (unsigned int)(long)hcpu;
-
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		register_cpu_online(cpu);
-		break;
-#ifdef CONFIG_HOTPLUG_CPU
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		unregister_cpu_online(cpu);
-		break;
 #endif
-	}
-	return NOTIFY_OK;
+	return 0;
 }
 
-static struct notifier_block sysfs_cpu_nb = {
-	.notifier_call	= sysfs_cpu_notify,
-};
-
 static void __init check_mmu_stats(void)
 {
 	unsigned long dummy1, err;
@@ -294,26 +272,21 @@ static void register_nodes(void)
 
 static int __init topology_init(void)
 {
-	int cpu;
+	int cpu, ret;
 
 	register_nodes();
 
 	check_mmu_stats();
 
-	cpu_notifier_register_begin();
-
 	for_each_possible_cpu(cpu) {
 		struct cpu *c = &per_cpu(cpu_devices, cpu);
 
 		register_cpu(c, cpu);
-		if (cpu_online(cpu))
-			register_cpu_online(cpu);
 	}
 
-	__register_cpu_notifier(&sysfs_cpu_nb);
-
-	cpu_notifier_register_done();
-
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "sparc/topology:online",
+				register_cpu_online, unregister_cpu_online);
+	WARN_ON(ret < 0);
 	return 0;
 }
 

arch/x86/include/asm/mce.h

@@ -295,9 +295,7 @@ void do_machine_check(struct pt_regs *, long);
 /*
  * Threshold handler
  */
-
 extern void (*mce_threshold_vector)(void);
-extern void (*threshold_cpu_callback)(unsigned long action, unsigned int cpu);
 
 /* Deferred error interrupt handler */
 extern void (*deferred_error_int_vector)(void);
@@ -375,6 +373,15 @@ struct smca_bank {
 extern struct smca_bank smca_banks[MAX_NR_BANKS];
 
 extern const char *smca_get_long_name(enum smca_bank_types t);
+
+extern int mce_threshold_create_device(unsigned int cpu);
+extern int mce_threshold_remove_device(unsigned int cpu);
+
+#else
+
+static inline int mce_threshold_create_device(unsigned int cpu) { return 0; };
+static inline int mce_threshold_remove_device(unsigned int cpu) { return 0; };
+
 #endif
 
 #endif /* _ASM_X86_MCE_H */

arch/x86/kernel/cpu/mcheck/mce.c

@@ -1792,6 +1792,14 @@ static void mce_start_timer(unsigned int cpu, struct timer_list *t)
 	add_timer_on(t, cpu);
 }
 
+static void __mcheck_cpu_setup_timer(void)
+{
+	struct timer_list *t = this_cpu_ptr(&mce_timer);
+	unsigned int cpu = smp_processor_id();
+
+	setup_pinned_timer(t, mce_timer_fn, cpu);
+}
+
 static void __mcheck_cpu_init_timer(void)
 {
 	struct timer_list *t = this_cpu_ptr(&mce_timer);
@@ -1843,7 +1851,7 @@ void mcheck_cpu_init(struct cpuinfo_x86 *c)
 	__mcheck_cpu_init_generic();
 	__mcheck_cpu_init_vendor(c);
 	__mcheck_cpu_init_clear_banks();
-	__mcheck_cpu_init_timer();
+	__mcheck_cpu_setup_timer();
 }
 
 /*
@@ -2303,8 +2311,6 @@ static struct bus_type mce_subsys = {
 
 DEFINE_PER_CPU(struct device *, mce_device);
 
-void (*threshold_cpu_callback)(unsigned long action, unsigned int cpu);
-
 static inline struct mce_bank *attr_to_bank(struct device_attribute *attr)
 {
 	return container_of(attr, struct mce_bank, attr);
@@ -2457,6 +2463,10 @@ static int mce_device_create(unsigned int cpu)
 	if (!mce_available(&boot_cpu_data))
 		return -EIO;
 
+	dev = per_cpu(mce_device, cpu);
+	if (dev)
+		return 0;
+
 	dev = kzalloc(sizeof *dev, GFP_KERNEL);
 	if (!dev)
 		return -ENOMEM;
@@ -2516,28 +2526,25 @@ static void mce_device_remove(unsigned int cpu)
 }
 
 /* Make sure there are no machine checks on offlined CPUs. */
-static void mce_disable_cpu(void *h)
+static void mce_disable_cpu(void)
 {
-	unsigned long action = *(unsigned long *)h;
-
 	if (!mce_available(raw_cpu_ptr(&cpu_info)))
 		return;
 
-	if (!(action & CPU_TASKS_FROZEN))
+	if (!cpuhp_tasks_frozen)
 		cmci_clear();
 
 	vendor_disable_error_reporting();
 }
 
-static void mce_reenable_cpu(void *h)
+static void mce_reenable_cpu(void)
 {
-	unsigned long action = *(unsigned long *)h;
 	int i;
 
 	if (!mce_available(raw_cpu_ptr(&cpu_info)))
 		return;
 
-	if (!(action & CPU_TASKS_FROZEN))
+	if (!cpuhp_tasks_frozen)
 		cmci_reenable();
 	for (i = 0; i < mca_cfg.banks; i++) {
 		struct mce_bank *b = &mce_banks[i];
@@ -2547,45 +2554,43 @@ static void mce_reenable_cpu(void *h)
 	}
 }
 
-/* Get notified when a cpu comes on/off. Be hotplug friendly. */
-static int
-mce_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
+static int mce_cpu_dead(unsigned int cpu)
+{
+	mce_intel_hcpu_update(cpu);
+
+	/* intentionally ignoring frozen here */
+	if (!cpuhp_tasks_frozen)
+		cmci_rediscover();
+	return 0;
+}
+
+static int mce_cpu_online(unsigned int cpu)
 {
-	unsigned int cpu = (unsigned long)hcpu;
 	struct timer_list *t = &per_cpu(mce_timer, cpu);
+	int ret;
 
-	switch (action & ~CPU_TASKS_FROZEN) {
-	case CPU_ONLINE:
-		mce_device_create(cpu);
-		if (threshold_cpu_callback)
-			threshold_cpu_callback(action, cpu);
-		break;
-	case CPU_DEAD:
-		if (threshold_cpu_callback)
-			threshold_cpu_callback(action, cpu);
-		mce_device_remove(cpu);
-		mce_intel_hcpu_update(cpu);
+	mce_device_create(cpu);
 
-		/* intentionally ignoring frozen here */
-		if (!(action & CPU_TASKS_FROZEN))
-			cmci_rediscover();
-		break;
-	case CPU_DOWN_PREPARE:
-		smp_call_function_single(cpu, mce_disable_cpu, &action, 1);
-		del_timer_sync(t);
-		break;
-	case CPU_DOWN_FAILED:
-		smp_call_function_single(cpu, mce_reenable_cpu, &action, 1);
-		mce_start_timer(cpu, t);
-		break;
+	ret = mce_threshold_create_device(cpu);
+	if (ret) {
+		mce_device_remove(cpu);
+		return ret;
 	}
-
-	return NOTIFY_OK;
+	mce_reenable_cpu();
+	mce_start_timer(cpu, t);
+	return 0;
 }
 
-static struct notifier_block mce_cpu_notifier = {
-	.notifier_call = mce_cpu_callback,
-};
+static int mce_cpu_pre_down(unsigned int cpu)
+{
+	struct timer_list *t = &per_cpu(mce_timer, cpu);
+
+	mce_disable_cpu();
+	del_timer_sync(t);
+	mce_threshold_remove_device(cpu);
+	mce_device_remove(cpu);
+	return 0;
+}
 
 static __init void mce_init_banks(void)
 {
@@ -2607,8 +2612,8 @@ static __init void mce_init_banks(void)
 
 static __init int mcheck_init_device(void)
 {
+	enum cpuhp_state hp_online;
 	int err;
-	int i = 0;
 
 	if (!mce_available(&boot_cpu_data)) {
 		err = -EIO;
@@ -2626,23 +2631,16 @@ static __init int mcheck_init_device(void)
 	if (err)
 		goto err_out_mem;
 
-	cpu_notifier_register_begin();
-	for_each_online_cpu(i) {
-		err = mce_device_create(i);
-		if (err) {
-			/*
-			 * Register notifier anyway (and do not unreg it) so
-			 * that we don't leave undeleted timers, see notifier
-			 * callback above.
-			 */
-			__register_hotcpu_notifier(&mce_cpu_notifier);
-			cpu_notifier_register_done();
-			goto err_device_create;
-		}
-	}
+	err = cpuhp_setup_state(CPUHP_X86_MCE_DEAD, "x86/mce:dead", NULL,
+				mce_cpu_dead);
+	if (err)
+		goto err_out_mem;
 
-	__register_hotcpu_notifier(&mce_cpu_notifier);
-	cpu_notifier_register_done();
+	err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/mce:online",
+				mce_cpu_online, mce_cpu_pre_down);
+	if (err < 0)
+		goto err_out_online;
+	hp_online = err;
 
 	register_syscore_ops(&mce_syscore_ops);
 
@@ -2655,16 +2653,10 @@ static __init int mcheck_init_device(void)
 
 err_register:
 	unregister_syscore_ops(&mce_syscore_ops);
+	cpuhp_remove_state(hp_online);
 
-err_device_create:
-	/*
-	 * We didn't keep track of which devices were created above, but
-	 * even if we had, the set of online cpus might have changed.
-	 * Play safe and remove for every possible cpu, since
-	 * mce_device_remove() will do the right thing.
-	 */
-	for_each_possible_cpu(i)
-		mce_device_remove(i);
+err_out_online:
+	cpuhp_remove_state(CPUHP_X86_MCE_DEAD);
 
 err_out_mem:
 	free_cpumask_var(mce_device_initialized);

arch/x86/kernel/cpu/mcheck/mce_amd.c

@@ -54,6 +54,8 @@
 /* Threshold LVT offset is at MSR0xC0000410[15:12] */
 #define SMCA_THR_LVT_OFF	0xF000
 
+static bool thresholding_en;
+
 static const char * const th_names[] = {
 	"load_store",
 	"insn_fetch",
@@ -1235,31 +1237,6 @@ static int threshold_create_bank(unsigned int cpu, unsigned int bank)
 	return err;
 }
 
-/* create dir/files for all valid threshold banks */
-static int threshold_create_device(unsigned int cpu)
-{
-	unsigned int bank;
-	struct threshold_bank **bp;
-	int err = 0;
-
-	bp = kzalloc(sizeof(struct threshold_bank *) * mca_cfg.banks,
-		     GFP_KERNEL);
-	if (!bp)
-		return -ENOMEM;
-
-	per_cpu(threshold_banks, cpu) = bp;
-
-	for (bank = 0; bank < mca_cfg.banks; ++bank) {
-		if (!(per_cpu(bank_map, cpu) & (1 << bank)))
-			continue;
-		err = threshold_create_bank(cpu, bank);
-		if (err)
-			return err;
-	}
-
-	return err;
-}
-
 static void deallocate_threshold_block(unsigned int cpu,
 						 unsigned int bank)
 {
@@ -1327,48 +1304,71 @@ free_out:
 	per_cpu(threshold_banks, cpu)[bank] = NULL;
 }
 
-static void threshold_remove_device(unsigned int cpu)
+int mce_threshold_remove_device(unsigned int cpu)
 {
 	unsigned int bank;
 
+	if (!thresholding_en)
+		return 0;
+
 	for (bank = 0; bank < mca_cfg.banks; ++bank) {
 		if (!(per_cpu(bank_map, cpu) & (1 << bank)))
 			continue;
 		threshold_remove_bank(cpu, bank);
 	}
 	kfree(per_cpu(threshold_banks, cpu));
+	per_cpu(threshold_banks, cpu) = NULL;
+	return 0;
 }
 
-/* get notified when a cpu comes on/off */
-static void
-amd_64_threshold_cpu_callback(unsigned long action, unsigned int cpu)
+/* create dir/files for all valid threshold banks */
+int mce_threshold_create_device(unsigned int cpu)
 {
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		threshold_create_device(cpu);
-		break;
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		threshold_remove_device(cpu);
-		break;
-	default:
-		break;
+	unsigned int bank;
+	struct threshold_bank **bp;
+	int err = 0;
+
+	if (!thresholding_en)
+		return 0;
+
+	bp = per_cpu(threshold_banks, cpu);
+	if (bp)
+		return 0;
+
+	bp = kzalloc(sizeof(struct threshold_bank *) * mca_cfg.banks,
+		     GFP_KERNEL);
+	if (!bp)
+		return -ENOMEM;
+
+	per_cpu(threshold_banks, cpu) = bp;
+
+	for (bank = 0; bank < mca_cfg.banks; ++bank) {
+		if (!(per_cpu(bank_map, cpu) & (1 << bank)))
+			continue;
+		err = threshold_create_bank(cpu, bank);
+		if (err)
+			goto err;
 	}
+	return err;
+err:
+	mce_threshold_remove_device(cpu);
+	return err;
 }
 
 static __init int threshold_init_device(void)
 {
 	unsigned lcpu = 0;
 
+	if (mce_threshold_vector == amd_threshold_interrupt)
+		thresholding_en = true;
+
 	/* to hit CPUs online before the notifier is up */
 	for_each_online_cpu(lcpu) {
-		int err = threshold_create_device(lcpu);
+		int err = mce_threshold_create_device(lcpu);
 
 		if (err)
 			return err;
 	}
-	threshold_cpu_callback = amd_64_threshold_cpu_callback;
 
 	return 0;
 }

arch/x86/kernel/cpu/mcheck/therm_throt.c

@@ -270,58 +270,32 @@ static void thermal_throttle_remove_dev(struct device *dev)
 }
 
 /* Get notified when a cpu comes on/off. Be hotplug friendly. */
-static int
-thermal_throttle_cpu_callback(struct notifier_block *nfb,
-			      unsigned long action,
-			      void *hcpu)
+static int thermal_throttle_online(unsigned int cpu)
 {
-	unsigned int cpu = (unsigned long)hcpu;
-	struct device *dev;
-	int err = 0;
-
-	dev = get_cpu_device(cpu);
-
-	switch (action) {
-	case CPU_UP_PREPARE:
-	case CPU_UP_PREPARE_FROZEN:
-		err = thermal_throttle_add_dev(dev, cpu);
-		WARN_ON(err);
-		break;
-	case CPU_UP_CANCELED:
-	case CPU_UP_CANCELED_FROZEN:
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		thermal_throttle_remove_dev(dev);
-		break;
-	}
-	return notifier_from_errno(err);
+	struct device *dev = get_cpu_device(cpu);
+
+	return thermal_throttle_add_dev(dev, cpu);
 }
 
-static struct notifier_block thermal_throttle_cpu_notifier =
+static int thermal_throttle_offline(unsigned int cpu)
 {
-	.notifier_call = thermal_throttle_cpu_callback,
-};
+	struct device *dev = get_cpu_device(cpu);
+
+	thermal_throttle_remove_dev(dev);
+	return 0;
+}
 
 static __init int thermal_throttle_init_device(void)
 {
-	unsigned int cpu = 0;
-	int err;
+	int ret;
 
 	if (!atomic_read(&therm_throt_en))
 		return 0;
 
-	cpu_notifier_register_begin();
-
-	/* connect live CPUs to sysfs */
-	for_each_online_cpu(cpu) {
-		err = thermal_throttle_add_dev(get_cpu_device(cpu), cpu);
-		WARN_ON(err);
-	}
-
-	__register_hotcpu_notifier(&thermal_throttle_cpu_notifier);
-	cpu_notifier_register_done();
-
-	return 0;
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/therm:online",
+				thermal_throttle_online,
+				thermal_throttle_offline);
+	return ret < 0 ? ret : 0;
 }
 device_initcall(thermal_throttle_init_device);
 

arch/x86/kernel/cpuid.c

@@ -45,6 +45,7 @@
 #include <asm/msr.h>
 
 static struct class *cpuid_class;
+static enum cpuhp_state cpuhp_cpuid_state;
 
 static void cpuid_smp_cpuid(void *cmd_block)
 {
@@ -111,7 +112,7 @@ 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;
 
@@ -120,35 +121,12 @@ 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));
@@ -156,15 +134,13 @@ static char *cpuid_devnode(struct device *dev, umode_t *mode)
 
 static int __init cpuid_init(void)
 {
-	int i, err = 0;
-	i = 0;
+	int err;
 
 	if (__register_chrdev(CPUID_MAJOR, 0, NR_CPUS,
 			      "cpu/cpuid", &cpuid_fops)) {
 		printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n",
 		       CPUID_MAJOR);
-		err = -EBUSY;
-		goto out;
+		return -EBUSY;
 	}
 	cpuid_class = class_create(THIS_MODULE, "cpuid");
 	if (IS_ERR(cpuid_class)) {
@@ -173,45 +149,28 @@ 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_AP_ONLINE_DYN, "x86/cpuid:online",
+				cpuid_device_create, cpuid_device_destroy);
+	if (err < 0)
+		goto out_class;
 
-	err = 0;
-	goto out;
+	cpuhp_cpuid_state = err;
+	return 0;
 
 out_class:
-	i = 0;
-	for_each_online_cpu(i) {
-		cpuid_device_destroy(i);
-	}
-	cpu_notifier_register_done();
 	class_destroy(cpuid_class);
 out_chrdev:
 	__unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
-out:
 	return err;
 }
+module_init(cpuid_init);
 
 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_cpuid_state);
 	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);
 module_exit(cpuid_exit);
 
 MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");

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>");

arch/x86/oprofile/nmi_int.c

@@ -339,10 +339,11 @@ fail:
 	return 0;
 }
 
-static void nmi_cpu_setup(void *dummy)
+static void nmi_cpu_setup(void)
 {
 	int cpu = smp_processor_id();
 	struct op_msrs *msrs = &per_cpu(cpu_msrs, cpu);
+
 	nmi_cpu_save_registers(msrs);
 	raw_spin_lock(&oprofilefs_lock);
 	model->setup_ctrs(model, msrs);
@@ -369,7 +370,7 @@ static void nmi_cpu_restore_registers(struct op_msrs *msrs)
 	}
 }
 
-static void nmi_cpu_shutdown(void *dummy)
+static void nmi_cpu_shutdown(void)
 {
 	unsigned int v;
 	int cpu = smp_processor_id();
@@ -387,20 +388,26 @@ static void nmi_cpu_shutdown(void *dummy)
 	nmi_cpu_restore_registers(msrs);
 }
 
-static void nmi_cpu_up(void *dummy)
+static int nmi_cpu_online(unsigned int cpu)
 {
+	local_irq_disable();
 	if (nmi_enabled)
-		nmi_cpu_setup(dummy);
+		nmi_cpu_setup();
 	if (ctr_running)
-		nmi_cpu_start(dummy);
+		nmi_cpu_start(NULL);
+	local_irq_enable();
+	return 0;
 }
 
-static void nmi_cpu_down(void *dummy)
+static int nmi_cpu_down_prep(unsigned int cpu)
 {
+	local_irq_disable();
 	if (ctr_running)
-		nmi_cpu_stop(dummy);
+		nmi_cpu_stop(NULL);
 	if (nmi_enabled)
-		nmi_cpu_shutdown(dummy);
+		nmi_cpu_shutdown();
+	local_irq_enable();
+	return 0;
 }
 
 static int nmi_create_files(struct dentry *root)
@@ -433,26 +440,7 @@ static int nmi_create_files(struct dentry *root)
 	return 0;
 }
 
-static int oprofile_cpu_notifier(struct notifier_block *b, unsigned long action,
-				 void *data)
-{
-	int cpu = (unsigned long)data;
-
-	switch (action & ~CPU_TASKS_FROZEN) {
-	case CPU_DOWN_FAILED:
-	case CPU_ONLINE:
-		smp_call_function_single(cpu, nmi_cpu_up, NULL, 0);
-		break;
-	case CPU_DOWN_PREPARE:
-		smp_call_function_single(cpu, nmi_cpu_down, NULL, 1);
-		break;
-	}
-	return NOTIFY_DONE;
-}
-
-static struct notifier_block oprofile_cpu_nb = {
-	.notifier_call = oprofile_cpu_notifier
-};
+static enum cpuhp_state cpuhp_nmi_online;
 
 static int nmi_setup(void)
 {
@@ -495,20 +483,17 @@ 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();
 	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();
-
+	err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/oprofile:online",
+				nmi_cpu_online, nmi_cpu_down_prep);
+	if (err < 0)
+		goto fail_nmi;
+	cpuhp_nmi_online = err;
 	return 0;
+fail_nmi:
+	unregister_nmi_handler(NMI_LOCAL, "oprofile");
 fail:
 	free_msrs();
 	return err;
@@ -518,17 +503,9 @@ 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();
-	on_each_cpu(nmi_cpu_shutdown, NULL, 1);
+	cpuhp_remove_state(cpuhp_nmi_online);
 	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();

arch/x86/pci/amd_bus.c

@@ -327,35 +327,18 @@ static int __init early_root_info_init(void)
 
 #define ENABLE_CF8_EXT_CFG      (1ULL << 46)
 
-static void enable_pci_io_ecs(void *unused)
+static int amd_bus_cpu_online(unsigned int cpu)
 {
 	u64 reg;
+
 	rdmsrl(MSR_AMD64_NB_CFG, reg);
 	if (!(reg & ENABLE_CF8_EXT_CFG)) {
 		reg |= ENABLE_CF8_EXT_CFG;
 		wrmsrl(MSR_AMD64_NB_CFG, reg);
 	}
+	return 0;
 }
 
-static int amd_cpu_notify(struct notifier_block *self, unsigned long action,
-			  void *hcpu)
-{
-	int cpu = (long)hcpu;
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		smp_call_function_single(cpu, enable_pci_io_ecs, NULL, 0);
-		break;
-	default:
-		break;
-	}
-	return NOTIFY_OK;
-}
-
-static struct notifier_block amd_cpu_notifier = {
-	.notifier_call	= amd_cpu_notify,
-};
-
 static void __init pci_enable_pci_io_ecs(void)
 {
 #ifdef CONFIG_AMD_NB
@@ -385,7 +368,7 @@ static void __init pci_enable_pci_io_ecs(void)
 
 static int __init pci_io_ecs_init(void)
 {
-	int cpu;
+	int ret;
 
 	/* assume all cpus from fam10h have IO ECS */
 	if (boot_cpu_data.x86 < 0x10)
@@ -395,12 +378,9 @@ static int __init pci_io_ecs_init(void)
 	if (early_pci_allowed())
 		pci_enable_pci_io_ecs();
 
-	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();
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "pci/amd_bus:online",
+				amd_bus_cpu_online, NULL);
+	WARN_ON(ret < 0);
 
 	pci_probe |= PCI_HAS_IO_ECS;
 

drivers/base/cacheinfo.c

@@ -498,57 +498,30 @@ err:
 	return rc;
 }
 
-static void cache_remove_dev(unsigned int cpu)
+static int cacheinfo_cpu_online(unsigned int cpu)
 {
-	if (!cpumask_test_cpu(cpu, &cache_dev_map))
-		return;
-	cpumask_clear_cpu(cpu, &cache_dev_map);
+	int rc = detect_cache_attributes(cpu);
 
-	cpu_cache_sysfs_exit(cpu);
+	if (rc)
+		return rc;
+	rc = cache_add_dev(cpu);
+	if (rc)
+		free_cache_attributes(cpu);
+	return rc;
 }
 
-static int cacheinfo_cpu_callback(struct notifier_block *nfb,
-				  unsigned long action, void *hcpu)
+static int cacheinfo_cpu_pre_down(unsigned int cpu)
 {
-	unsigned int cpu = (unsigned long)hcpu;
-	int rc = 0;
-
-	switch (action & ~CPU_TASKS_FROZEN) {
-	case CPU_ONLINE:
-		rc = detect_cache_attributes(cpu);
-		if (!rc)
-			rc = cache_add_dev(cpu);
-		break;
-	case CPU_DEAD:
-		cache_remove_dev(cpu);
-		free_cache_attributes(cpu);
-		break;
-	}
-	return notifier_from_errno(rc);
+	if (cpumask_test_and_clear_cpu(cpu, &cache_dev_map))
+		cpu_cache_sysfs_exit(cpu);
+
+	free_cache_attributes(cpu);
+	return 0;
 }
 
 static int __init cacheinfo_sysfs_init(void)
 {
-	int cpu, rc = 0;
-
-	cpu_notifier_register_begin();
-
-	for_each_online_cpu(cpu) {
-		rc = detect_cache_attributes(cpu);
-		if (rc)
-			goto out;
-		rc = cache_add_dev(cpu);
-		if (rc) {
-			free_cache_attributes(cpu);
-			pr_err("error populating cacheinfo..cpu%d\n", cpu);
-			goto out;
-		}
-	}
-	__hotcpu_notifier(cacheinfo_cpu_callback, 0);
-
-out:
-	cpu_notifier_register_done();
-	return rc;
+	return cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "base/cacheinfo:online",
+				 cacheinfo_cpu_online, cacheinfo_cpu_pre_down);
 }
-
 device_initcall(cacheinfo_sysfs_init);

drivers/base/topology.c

@@ -118,51 +118,19 @@ static int topology_add_dev(unsigned int cpu)
 	return sysfs_create_group(&dev->kobj, &topology_attr_group);
 }
 
-static void topology_remove_dev(unsigned int cpu)
+static int topology_remove_dev(unsigned int cpu)
 {
 	struct device *dev = get_cpu_device(cpu);
 
 	sysfs_remove_group(&dev->kobj, &topology_attr_group);
-}
-
-static int topology_cpu_callback(struct notifier_block *nfb,
-				 unsigned long action, void *hcpu)
-{
-	unsigned int cpu = (unsigned long)hcpu;
-	int rc = 0;
-
-	switch (action) {
-	case CPU_UP_PREPARE:
-	case CPU_UP_PREPARE_FROZEN:
-		rc = topology_add_dev(cpu);
-		break;
-	case CPU_UP_CANCELED:
-	case CPU_UP_CANCELED_FROZEN:
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		topology_remove_dev(cpu);
-		break;
-	}
-	return notifier_from_errno(rc);
+	return 0;
 }
 
 static int topology_sysfs_init(void)
 {
-	int cpu;
-	int rc = 0;
-
-	cpu_notifier_register_begin();
-
-	for_each_online_cpu(cpu) {
-		rc = topology_add_dev(cpu);
-		if (rc)
-			goto out;
-	}
-	__hotcpu_notifier(topology_cpu_callback, 0);
-
-out:
-	cpu_notifier_register_done();
-	return rc;
+	return cpuhp_setup_state(CPUHP_TOPOLOGY_PREPARE,
+				 "base/topology:prepare", topology_add_dev,
+				 topology_remove_dev);
 }
 
 device_initcall(topology_sysfs_init);

drivers/block/zram/zcomp.c

@@ -160,82 +160,56 @@ int zcomp_decompress(struct zcomp_strm *zstrm,
 			dst, &dst_len);
 }
 
-static int __zcomp_cpu_notifier(struct zcomp *comp,
-		unsigned long action, unsigned long cpu)
+int zcomp_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
 {
+	struct zcomp *comp = hlist_entry(node, struct zcomp, node);
 	struct zcomp_strm *zstrm;
 
-	switch (action) {
-	case CPU_UP_PREPARE:
-		if (WARN_ON(*per_cpu_ptr(comp->stream, cpu)))
-			break;
-		zstrm = zcomp_strm_alloc(comp);
-		if (IS_ERR_OR_NULL(zstrm)) {
-			pr_err("Can't allocate a compression stream\n");
-			return NOTIFY_BAD;
-		}
-		*per_cpu_ptr(comp->stream, cpu) = zstrm;
-		break;
-	case CPU_DEAD:
-	case CPU_UP_CANCELED:
-		zstrm = *per_cpu_ptr(comp->stream, cpu);
-		if (!IS_ERR_OR_NULL(zstrm))
-			zcomp_strm_free(zstrm);
-		*per_cpu_ptr(comp->stream, cpu) = NULL;
-		break;
-	default:
-		break;
+	if (WARN_ON(*per_cpu_ptr(comp->stream, cpu)))
+		return 0;
+
+	zstrm = zcomp_strm_alloc(comp);
+	if (IS_ERR_OR_NULL(zstrm)) {
+		pr_err("Can't allocate a compression stream\n");
+		return -ENOMEM;
 	}
-	return NOTIFY_OK;
+	*per_cpu_ptr(comp->stream, cpu) = zstrm;
+	return 0;
 }
 
-static int zcomp_cpu_notifier(struct notifier_block *nb,
-		unsigned long action, void *pcpu)
+int zcomp_cpu_dead(unsigned int cpu, struct hlist_node *node)
 {
-	unsigned long cpu = (unsigned long)pcpu;
-	struct zcomp *comp = container_of(nb, typeof(*comp), notifier);
+	struct zcomp *comp = hlist_entry(node, struct zcomp, node);
+	struct zcomp_strm *zstrm;
 
-	return __zcomp_cpu_notifier(comp, action, cpu);
+	zstrm = *per_cpu_ptr(comp->stream, cpu);
+	if (!IS_ERR_OR_NULL(zstrm))
+		zcomp_strm_free(zstrm);
+	*per_cpu_ptr(comp->stream, cpu) = NULL;
+	return 0;
 }
 
 static int zcomp_init(struct zcomp *comp)
 {
-	unsigned long cpu;
 	int ret;
 
-	comp->notifier.notifier_call = zcomp_cpu_notifier;
-
 	comp->stream = alloc_percpu(struct zcomp_strm *);
 	if (!comp->stream)
 		return -ENOMEM;
 
-	cpu_notifier_register_begin();
-	for_each_online_cpu(cpu) {
-		ret = __zcomp_cpu_notifier(comp, CPU_UP_PREPARE, cpu);
-		if (ret == NOTIFY_BAD)
-			goto cleanup;
-	}
-	__register_cpu_notifier(&comp->notifier);
-	cpu_notifier_register_done();
+	ret = cpuhp_state_add_instance(CPUHP_ZCOMP_PREPARE, &comp->node);
+	if (ret < 0)
+		goto cleanup;
 	return 0;
 
 cleanup:
-	for_each_online_cpu(cpu)
-		__zcomp_cpu_notifier(comp, CPU_UP_CANCELED, cpu);
-	cpu_notifier_register_done();
-	return -ENOMEM;
+	free_percpu(comp->stream);
+	return ret;
 }
 
 void zcomp_destroy(struct zcomp *comp)
 {
-	unsigned long cpu;
-
-	cpu_notifier_register_begin();
-	for_each_online_cpu(cpu)
-		__zcomp_cpu_notifier(comp, CPU_UP_CANCELED, cpu);
-	__unregister_cpu_notifier(&comp->notifier);
-	cpu_notifier_register_done();
-
+	cpuhp_state_remove_instance(CPUHP_ZCOMP_PREPARE, &comp->node);
 	free_percpu(comp->stream);
 	kfree(comp);
 }

drivers/block/zram/zcomp.h

@@ -19,11 +19,12 @@ struct zcomp_strm {
 /* dynamic per-device compression frontend */
 struct zcomp {
 	struct zcomp_strm * __percpu *stream;
-	struct notifier_block notifier;
-
 	const char *name;
+	struct hlist_node node;
 };
 
+int zcomp_cpu_up_prepare(unsigned int cpu, struct hlist_node *node);
+int zcomp_cpu_dead(unsigned int cpu, struct hlist_node *node);
 ssize_t zcomp_available_show(const char *comp, char *buf);
 bool zcomp_available_algorithm(const char *comp);
 

drivers/block/zram/zram_drv.c

@@ -30,6 +30,7 @@
 #include <linux/err.h>
 #include <linux/idr.h>
 #include <linux/sysfs.h>
+#include <linux/cpuhotplug.h>
 
 #include "zram_drv.h"
 
@@ -1443,15 +1444,22 @@ static void destroy_devices(void)
 	idr_for_each(&zram_index_idr, &zram_remove_cb, NULL);
 	idr_destroy(&zram_index_idr);
 	unregister_blkdev(zram_major, "zram");
+	cpuhp_remove_multi_state(CPUHP_ZCOMP_PREPARE);
 }
 
 static int __init zram_init(void)
 {
 	int ret;
 
+	ret = cpuhp_setup_state_multi(CPUHP_ZCOMP_PREPARE, "block/zram:prepare",
+				      zcomp_cpu_up_prepare, zcomp_cpu_dead);
+	if (ret < 0)
+		return ret;
+
 	ret = class_register(&zram_control_class);
 	if (ret) {
 		pr_err("Unable to register zram-control class\n");
+		cpuhp_remove_multi_state(CPUHP_ZCOMP_PREPARE);
 		return ret;
 	}
 
@@ -1459,6 +1467,7 @@ static int __init zram_init(void)
 	if (zram_major <= 0) {
 		pr_err("Unable to get major number\n");
 		class_unregister(&zram_control_class);
+		cpuhp_remove_multi_state(CPUHP_ZCOMP_PREPARE);
 		return -EBUSY;
 	}
 

drivers/iommu/intel-iommu.c

@@ -4688,25 +4688,13 @@ static void free_all_cpu_cached_iovas(unsigned int cpu)
 	}
 }
 
-static int intel_iommu_cpu_notifier(struct notifier_block *nfb,
-				    unsigned long action, void *v)
+static int intel_iommu_cpu_dead(unsigned int cpu)
 {
-	unsigned int cpu = (unsigned long)v;
-
-	switch (action) {
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		free_all_cpu_cached_iovas(cpu);
-		flush_unmaps_timeout(cpu);
-		break;
-	}
-	return NOTIFY_OK;
+	free_all_cpu_cached_iovas(cpu);
+	flush_unmaps_timeout(cpu);
+	return 0;
 }
 
-static struct notifier_block intel_iommu_cpu_nb = {
-	.notifier_call = intel_iommu_cpu_notifier,
-};
-
 static ssize_t intel_iommu_show_version(struct device *dev,
 					struct device_attribute *attr,
 					char *buf)
@@ -4855,8 +4843,8 @@ int __init intel_iommu_init(void)
 	bus_register_notifier(&pci_bus_type, &device_nb);
 	if (si_domain && !hw_pass_through)
 		register_memory_notifier(&intel_iommu_memory_nb);
-	register_hotcpu_notifier(&intel_iommu_cpu_nb);
-
+	cpuhp_setup_state(CPUHP_IOMMU_INTEL_DEAD, "iommu/intel:dead", NULL,
+			  intel_iommu_cpu_dead);
 	intel_iommu_enabled = 1;
 
 	return 0;

drivers/oprofile/nmi_timer_int.c

@@ -59,25 +59,16 @@ static void nmi_timer_stop_cpu(int cpu)
 		perf_event_disable(event);
 }
 
-static int nmi_timer_cpu_notifier(struct notifier_block *b, unsigned long action,
-				  void *data)
+static int nmi_timer_cpu_online(unsigned int cpu)
 {
-	int cpu = (unsigned long)data;
-	switch (action) {
-	case CPU_DOWN_FAILED:
-	case CPU_ONLINE:
-		nmi_timer_start_cpu(cpu);
-		break;
-	case CPU_DOWN_PREPARE:
-		nmi_timer_stop_cpu(cpu);
-		break;
-	}
-	return NOTIFY_DONE;
+	nmi_timer_start_cpu(cpu);
+	return 0;
+}
+static int nmi_timer_cpu_predown(unsigned int cpu)
+{
+	nmi_timer_stop_cpu(cpu);
+	return 0;
 }
-
-static struct notifier_block nmi_timer_cpu_nb = {
-	.notifier_call = nmi_timer_cpu_notifier
-};
 
 static int nmi_timer_start(void)
 {
@@ -103,13 +94,14 @@ static void nmi_timer_stop(void)
 	put_online_cpus();
 }
 
+static enum cpuhp_state hp_online;
+
 static void nmi_timer_shutdown(void)
 {
 	struct perf_event *event;
 	int cpu;
 
-	cpu_notifier_register_begin();
-	__unregister_cpu_notifier(&nmi_timer_cpu_nb);
+	cpuhp_remove_state(hp_online);
 	for_each_possible_cpu(cpu) {
 		event = per_cpu(nmi_timer_events, cpu);
 		if (!event)
@@ -118,13 +110,11 @@ static void nmi_timer_shutdown(void)
 		per_cpu(nmi_timer_events, cpu) = NULL;
 		perf_event_release_kernel(event);
 	}
-
-	cpu_notifier_register_done();
 }
 
 static int nmi_timer_setup(void)
 {
-	int cpu, err;
+	int err;
 	u64 period;
 
 	/* clock cycles per tick: */
@@ -132,24 +122,14 @@ static int nmi_timer_setup(void)
 	do_div(period, HZ);
 	nmi_timer_attr.sample_period = period;
 
-	cpu_notifier_register_begin();
-	err = __register_cpu_notifier(&nmi_timer_cpu_nb);
-	if (err)
-		goto out;
-
-	/* can't attach events to offline cpus: */
-	for_each_online_cpu(cpu) {
-		err = nmi_timer_start_cpu(cpu);
-		if (err) {
-			cpu_notifier_register_done();
-			nmi_timer_shutdown();
-			return err;
-		}
+	err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "oprofile/nmi:online",
+				nmi_timer_cpu_online, nmi_timer_cpu_predown);
+	if (err < 0) {
+		nmi_timer_shutdown();
+		return err;
 	}
-
-out:
-	cpu_notifier_register_done();
-	return err;
+	hp_online = err;
+	return 0;
 }
 
 int __init op_nmi_timer_init(struct oprofile_operations *ops)

drivers/pci/host/pci-xgene-msi.c

@@ -360,16 +360,16 @@ static void xgene_msi_isr(struct irq_desc *desc)
 	chained_irq_exit(chip, desc);
 }
 
+static enum cpuhp_state pci_xgene_online;
+
 static int xgene_msi_remove(struct platform_device *pdev)
 {
-	int virq, i;
 	struct xgene_msi *msi = platform_get_drvdata(pdev);
 
-	for (i = 0; i < NR_HW_IRQS; i++) {
-		virq = msi->msi_groups[i].gic_irq;
-		if (virq != 0)
-			irq_set_chained_handler_and_data(virq, NULL, NULL);
-	}
+	if (pci_xgene_online)
+		cpuhp_remove_state(pci_xgene_online);
+	cpuhp_remove_state(CPUHP_PCI_XGENE_DEAD);
+
 	kfree(msi->msi_groups);
 
 	kfree(msi->bitmap);
@@ -427,7 +427,7 @@ static int xgene_msi_hwirq_alloc(unsigned int cpu)
 	return 0;
 }
 
-static void xgene_msi_hwirq_free(unsigned int cpu)
+static int xgene_msi_hwirq_free(unsigned int cpu)
 {
 	struct xgene_msi *msi = &xgene_msi_ctrl;
 	struct xgene_msi_group *msi_group;
@@ -441,33 +441,9 @@ static void xgene_msi_hwirq_free(unsigned int cpu)
 		irq_set_chained_handler_and_data(msi_group->gic_irq, NULL,
 						 NULL);
 	}
+	return 0;
 }
 
-static int xgene_msi_cpu_callback(struct notifier_block *nfb,
-				  unsigned long action, void *hcpu)
-{
-	unsigned cpu = (unsigned long)hcpu;
-
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		xgene_msi_hwirq_alloc(cpu);
-		break;
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		xgene_msi_hwirq_free(cpu);
-		break;
-	default:
-		break;
-	}
-
-	return NOTIFY_OK;
-}
-
-static struct notifier_block xgene_msi_cpu_notifier = {
-	.notifier_call = xgene_msi_cpu_callback,
-};
-
 static const struct of_device_id xgene_msi_match_table[] = {
 	{.compatible = "apm,xgene1-msi"},
 	{},
@@ -478,7 +454,6 @@ static int xgene_msi_probe(struct platform_device *pdev)
 	struct resource *res;
 	int rc, irq_index;
 	struct xgene_msi *xgene_msi;
-	unsigned int cpu;
 	int virt_msir;
 	u32 msi_val, msi_idx;
 
@@ -540,28 +515,22 @@ static int xgene_msi_probe(struct platform_device *pdev)
 		}
 	}
 
-	cpu_notifier_register_begin();
-
-	for_each_online_cpu(cpu)
-		if (xgene_msi_hwirq_alloc(cpu)) {
-			dev_err(&pdev->dev, "failed to register MSI handlers\n");
-			cpu_notifier_register_done();
-			goto error;
-		}
-
-	rc = __register_hotcpu_notifier(&xgene_msi_cpu_notifier);
-	if (rc) {
-		dev_err(&pdev->dev, "failed to add CPU MSI notifier\n");
-		cpu_notifier_register_done();
-		goto error;
-	}
-
-	cpu_notifier_register_done();
+	rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "pci/xgene:online",
+			       xgene_msi_hwirq_alloc, NULL);
+	if (rc)
+		goto err_cpuhp;
+	pci_xgene_online = rc;
+	rc = cpuhp_setup_state(CPUHP_PCI_XGENE_DEAD, "pci/xgene:dead", NULL,
+			       xgene_msi_hwirq_free);
+	if (rc)
+		goto err_cpuhp;
 
 	dev_info(&pdev->dev, "APM X-Gene PCIe MSI driver loaded\n");
 
 	return 0;
 
+err_cpuhp:
+	dev_err(&pdev->dev, "failed to add CPU MSI notifier\n");
 error:
 	xgene_msi_remove(pdev);
 	return rc;

drivers/soc/fsl/qbman/bman_portal.c

@@ -53,58 +53,38 @@ static struct bman_portal *init_pcfg(struct bm_portal_config *pcfg)
 	return p;
 }
 
-static void bman_offline_cpu(unsigned int cpu)
+static int bman_offline_cpu(unsigned int cpu)
 {
 	struct bman_portal *p = affine_bportals[cpu];
 	const struct bm_portal_config *pcfg;
 
 	if (!p)
-		return;
+		return 0;
 
 	pcfg = bman_get_bm_portal_config(p);
 	if (!pcfg)
-		return;
+		return 0;
 
 	irq_set_affinity(pcfg->irq, cpumask_of(0));
+	return 0;
 }
 
-static void bman_online_cpu(unsigned int cpu)
+static int bman_online_cpu(unsigned int cpu)
 {
 	struct bman_portal *p = affine_bportals[cpu];
 	const struct bm_portal_config *pcfg;
 
 	if (!p)
-		return;
+		return 0;
 
 	pcfg = bman_get_bm_portal_config(p);
 	if (!pcfg)
-		return;
+		return 0;
 
 	irq_set_affinity(pcfg->irq, cpumask_of(cpu));
+	return 0;
 }
 
-static int bman_hotplug_cpu_callback(struct notifier_block *nfb,
-				     unsigned long action, void *hcpu)
-{
-	unsigned int cpu = (unsigned long)hcpu;
-
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		bman_online_cpu(cpu);
-		break;
-	case CPU_DOWN_PREPARE:
-	case CPU_DOWN_PREPARE_FROZEN:
-		bman_offline_cpu(cpu);
-	}
-
-	return NOTIFY_OK;
-}
-
-static struct notifier_block bman_hotplug_cpu_notifier = {
-	.notifier_call = bman_hotplug_cpu_callback,
-};
-
 static int bman_portal_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -210,8 +190,14 @@ static int __init bman_portal_driver_register(struct platform_driver *drv)
 	if (ret < 0)
 		return ret;
 
-	register_hotcpu_notifier(&bman_hotplug_cpu_notifier);
-
+	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
+					"soc/qbman_portal:online",
+					bman_online_cpu, bman_offline_cpu);
+	if (ret < 0) {
+		pr_err("bman: failed to register hotplug callbacks.\n");
+		platform_driver_unregister(drv);
+		return ret;
+	}
 	return 0;
 }
 

drivers/soc/fsl/qbman/qman_portal.c

@@ -179,7 +179,7 @@ static void qman_portal_update_sdest(const struct qm_portal_config *pcfg,
 	qman_set_sdest(pcfg->channel, cpu);
 }
 
-static void qman_offline_cpu(unsigned int cpu)
+static int qman_offline_cpu(unsigned int cpu)
 {
 	struct qman_portal *p;
 	const struct qm_portal_config *pcfg;
@@ -192,9 +192,10 @@ static void qman_offline_cpu(unsigned int cpu)
 			qman_portal_update_sdest(pcfg, 0);
 		}
 	}
+	return 0;
 }
 
-static void qman_online_cpu(unsigned int cpu)
+static int qman_online_cpu(unsigned int cpu)
 {
 	struct qman_portal *p;
 	const struct qm_portal_config *pcfg;
@@ -207,31 +208,9 @@ static void qman_online_cpu(unsigned int cpu)
 			qman_portal_update_sdest(pcfg, cpu);
 		}
 	}
+	return 0;
 }
 
-static int qman_hotplug_cpu_callback(struct notifier_block *nfb,
-				     unsigned long action, void *hcpu)
-{
-	unsigned int cpu = (unsigned long)hcpu;
-
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		qman_online_cpu(cpu);
-		break;
-	case CPU_DOWN_PREPARE:
-	case CPU_DOWN_PREPARE_FROZEN:
-		qman_offline_cpu(cpu);
-	default:
-		break;
-	}
-	return NOTIFY_OK;
-}
-
-static struct notifier_block qman_hotplug_cpu_notifier = {
-	.notifier_call = qman_hotplug_cpu_callback,
-};
-
 static int qman_portal_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -346,8 +325,14 @@ static int __init qman_portal_driver_register(struct platform_driver *drv)
 	if (ret < 0)
 		return ret;
 
-	register_hotcpu_notifier(&qman_hotplug_cpu_notifier);
-
+	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
+					"soc/qman_portal:online",
+					qman_online_cpu, qman_offline_cpu);
+	if (ret < 0) {
+		pr_err("qman: failed to register hotplug callbacks.\n");
+		platform_driver_unregister(drv);
+		return ret;
+	}
 	return 0;
 }
 

drivers/watchdog/octeon-wdt-main.c

@@ -374,7 +374,7 @@ void octeon_wdt_nmi_stage3(u64 reg[32])
 	octeon_wdt_write_string("*** Chip soft reset soon ***\r\n");
 }
 
-static void octeon_wdt_disable_interrupt(int cpu)
+static int octeon_wdt_cpu_pre_down(unsigned int cpu)
 {
 	unsigned int core;
 	unsigned int irq;
@@ -392,9 +392,10 @@ static void octeon_wdt_disable_interrupt(int cpu)
 	cvmx_write_csr(CVMX_CIU_WDOGX(core), ciu_wdog.u64);
 
 	free_irq(irq, octeon_wdt_poke_irq);
+	return 0;
 }
 
-static void octeon_wdt_setup_interrupt(int cpu)
+static int octeon_wdt_cpu_online(unsigned int cpu)
 {
 	unsigned int core;
 	unsigned int irq;
@@ -424,25 +425,8 @@ static void octeon_wdt_setup_interrupt(int cpu)
 	ciu_wdog.s.len = timeout_cnt;
 	ciu_wdog.s.mode = 3;	/* 3 = Interrupt + NMI + Soft-Reset */
 	cvmx_write_csr(CVMX_CIU_WDOGX(core), ciu_wdog.u64);
-}
 
-static int octeon_wdt_cpu_callback(struct notifier_block *nfb,
-					   unsigned long action, void *hcpu)
-{
-	unsigned int cpu = (unsigned long)hcpu;
-
-	switch (action & ~CPU_TASKS_FROZEN) {
-	case CPU_DOWN_PREPARE:
-		octeon_wdt_disable_interrupt(cpu);
-		break;
-	case CPU_ONLINE:
-	case CPU_DOWN_FAILED:
-		octeon_wdt_setup_interrupt(cpu);
-		break;
-	default:
-		break;
-	}
-	return NOTIFY_OK;
+	return 0;
 }
 
 static int octeon_wdt_ping(struct watchdog_device __always_unused *wdog)
@@ -531,10 +515,6 @@ static int octeon_wdt_stop(struct watchdog_device *wdog)
 	return 0;
 }
 
-static struct notifier_block octeon_wdt_cpu_notifier = {
-	.notifier_call = octeon_wdt_cpu_callback,
-};
-
 static const struct watchdog_info octeon_wdt_info = {
 	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 	.identity = "OCTEON",
@@ -553,6 +533,7 @@ static struct watchdog_device octeon_wdt = {
 	.ops	= &octeon_wdt_ops,
 };
 
+static enum cpuhp_state octeon_wdt_online;
 /**
  * Module/ driver initialization.
  *
@@ -562,7 +543,6 @@ static int __init octeon_wdt_init(void)
 {
 	int i;
 	int ret;
-	int cpu;
 	u64 *ptr;
 
 	/*
@@ -610,14 +590,16 @@ static int __init octeon_wdt_init(void)
 
 	cpumask_clear(&irq_enabled_cpus);
 
-	cpu_notifier_register_begin();
-	for_each_online_cpu(cpu)
-		octeon_wdt_setup_interrupt(cpu);
-
-	__register_hotcpu_notifier(&octeon_wdt_cpu_notifier);
-	cpu_notifier_register_done();
-
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "watchdog/octeon:online",
+				octeon_wdt_cpu_online, octeon_wdt_cpu_pre_down);
+	if (ret < 0)
+		goto err;
+	octeon_wdt_online = ret;
 	return 0;
+err:
+	cvmx_write_csr(CVMX_MIO_BOOT_LOC_CFGX(0), 0);
+	watchdog_unregister_device(&octeon_wdt);
+	return ret;
 }
 
 /**
@@ -625,22 +607,8 @@ static int __init octeon_wdt_init(void)
  */
 static void __exit octeon_wdt_cleanup(void)
 {
-	int cpu;
-
 	watchdog_unregister_device(&octeon_wdt);
-
-	cpu_notifier_register_begin();
-	__unregister_hotcpu_notifier(&octeon_wdt_cpu_notifier);
-
-	for_each_online_cpu(cpu) {
-		int core = cpu2core(cpu);
-		/* Disable the watchdog */
-		cvmx_write_csr(CVMX_CIU_WDOGX(core), 0);
-		/* Free the interrupt handler */
-		free_irq(OCTEON_IRQ_WDOG0 + core, octeon_wdt_poke_irq);
-	}
-
-	cpu_notifier_register_done();
+	cpuhp_remove_state(octeon_wdt_online);
 
 	/*
 	 * Disable the boot-bus memory, the code it points to is soon

fs/buffer.c

@@ -3403,7 +3403,7 @@ void free_buffer_head(struct buffer_head *bh)
 }
 EXPORT_SYMBOL(free_buffer_head);
 
-static void buffer_exit_cpu(int cpu)
+static int buffer_exit_cpu_dead(unsigned int cpu)
 {
 	int i;
 	struct bh_lru *b = &per_cpu(bh_lrus, cpu);
@@ -3414,14 +3414,7 @@ static void buffer_exit_cpu(int cpu)
 	}
 	this_cpu_add(bh_accounting.nr, per_cpu(bh_accounting, cpu).nr);
 	per_cpu(bh_accounting, cpu).nr = 0;
-}
-
-static int buffer_cpu_notify(struct notifier_block *self,
-			      unsigned long action, void *hcpu)
-{
-	if (action == CPU_DEAD || action == CPU_DEAD_FROZEN)
-		buffer_exit_cpu((unsigned long)hcpu);
-	return NOTIFY_OK;
+	return 0;
 }
 
 /**
@@ -3471,6 +3464,7 @@ EXPORT_SYMBOL(bh_submit_read);
 void __init buffer_init(void)
 {
 	unsigned long nrpages;
+	int ret;
 
 	bh_cachep = kmem_cache_create("buffer_head",
 			sizeof(struct buffer_head), 0,
@@ -3483,5 +3477,7 @@ void __init buffer_init(void)
 	 */
 	nrpages = (nr_free_buffer_pages() * 10) / 100;
 	max_buffer_heads = nrpages * (PAGE_SIZE / sizeof(struct buffer_head));
-	hotcpu_notifier(buffer_cpu_notify, 0);
+	ret = cpuhp_setup_state_nocalls(CPUHP_FS_BUFF_DEAD, "fs/buffer:dead",
+					NULL, buffer_exit_cpu_dead);
+	WARN_ON(ret < 0);
 }

include/linux/cpuhotplug.h

@@ -16,9 +16,11 @@ enum cpuhp_state {
 	CPUHP_PERF_SUPERH,
 	CPUHP_X86_HPET_DEAD,
 	CPUHP_X86_APB_DEAD,
+	CPUHP_X86_MCE_DEAD,
 	CPUHP_VIRT_NET_DEAD,
 	CPUHP_SLUB_DEAD,
 	CPUHP_MM_WRITEBACK_DEAD,
+	CPUHP_MM_VMSTAT_DEAD,
 	CPUHP_SOFTIRQ_DEAD,
 	CPUHP_NET_MVNETA_DEAD,
 	CPUHP_CPUIDLE_DEAD,
@@ -30,6 +32,15 @@ enum cpuhp_state {
 	CPUHP_ACPI_CPUDRV_DEAD,
 	CPUHP_S390_PFAULT_DEAD,
 	CPUHP_BLK_MQ_DEAD,
+	CPUHP_FS_BUFF_DEAD,
+	CPUHP_PRINTK_DEAD,
+	CPUHP_MM_MEMCQ_DEAD,
+	CPUHP_PERCPU_CNT_DEAD,
+	CPUHP_RADIX_DEAD,
+	CPUHP_PAGE_ALLOC_DEAD,
+	CPUHP_NET_DEV_DEAD,
+	CPUHP_PCI_XGENE_DEAD,
+	CPUHP_IOMMU_INTEL_DEAD,
 	CPUHP_WORKQUEUE_PREP,
 	CPUHP_POWER_NUMA_PREPARE,
 	CPUHP_HRTIMERS_PREPARE,
@@ -49,6 +60,16 @@ enum cpuhp_state {
 	CPUHP_ARM_SHMOBILE_SCU_PREPARE,
 	CPUHP_SH_SH3X_PREPARE,
 	CPUHP_BLK_MQ_PREPARE,
+	CPUHP_NET_FLOW_PREPARE,
+	CPUHP_TOPOLOGY_PREPARE,
+	CPUHP_NET_IUCV_PREPARE,
+	CPUHP_ARM_BL_PREPARE,
+	CPUHP_TRACE_RB_PREPARE,
+	CPUHP_MM_ZS_PREPARE,
+	CPUHP_MM_ZSWP_MEM_PREPARE,
+	CPUHP_MM_ZSWP_POOL_PREPARE,
+	CPUHP_KVM_PPC_BOOK3S_PREPARE,
+	CPUHP_ZCOMP_PREPARE,
 	CPUHP_TIMERS_DEAD,
 	CPUHP_NOTF_ERR_INJ_PREPARE,
 	CPUHP_MIPS_SOC_PREPARE,

include/linux/ring_buffer.h

@@ -198,4 +198,10 @@ enum ring_buffer_flags {
 	RB_FL_OVERWRITE		= 1 << 0,
 };
 
+#ifdef CONFIG_RING_BUFFER
+int trace_rb_cpu_prepare(unsigned int cpu, struct hlist_node *node);
+#else
+#define trace_rb_cpu_prepare	NULL
+#endif
+
 #endif /* _LINUX_RING_BUFFER_H */

include/net/flow.h

@@ -246,6 +246,7 @@ struct flow_cache_object *flow_cache_lookup(struct net *net,
 					    void *ctx);
 int flow_cache_init(struct net *net);
 void flow_cache_fini(struct net *net);
+void flow_cache_hp_init(void);
 
 void flow_cache_flush(struct net *net);
 void flow_cache_flush_deferred(struct net *net);

include/net/flowcache.h

@@ -17,7 +17,7 @@ struct flow_cache_percpu {
 struct flow_cache {
 	u32				hash_shift;
 	struct flow_cache_percpu __percpu *percpu;
-	struct notifier_block		hotcpu_notifier;
+	struct hlist_node		node;
 	int				low_watermark;
 	int				high_watermark;
 	struct timer_list		rnd_timer;

kernel/printk/printk.c

@@ -2166,27 +2166,20 @@ void resume_console(void)
 
 /**
  * console_cpu_notify - print deferred console messages after CPU hotplug
- * @self: notifier struct
- * @action: CPU hotplug event
- * @hcpu: unused
+ * @cpu: unused
  *
  * If printk() is called from a CPU that is not online yet, the messages
  * will be spooled but will not show up on the console.  This function is
  * called when a new CPU comes online (or fails to come up), and ensures
  * that any such output gets printed.
  */
-static int console_cpu_notify(struct notifier_block *self,
-	unsigned long action, void *hcpu)
-{
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_DEAD:
-	case CPU_DOWN_FAILED:
-	case CPU_UP_CANCELED:
+static int console_cpu_notify(unsigned int cpu)
+{
+	if (!cpuhp_tasks_frozen) {
 		console_lock();
 		console_unlock();
 	}
-	return NOTIFY_OK;
+	return 0;
 }
 
 /**
@@ -2824,6 +2817,7 @@ EXPORT_SYMBOL(unregister_console);
 static int __init printk_late_init(void)
 {
 	struct console *con;
+	int ret;
 
 	for_each_console(con) {
 		if (!keep_bootcon && con->flags & CON_BOOT) {
@@ -2838,7 +2832,12 @@ static int __init printk_late_init(void)
 				unregister_console(con);
 		}
 	}
-	hotcpu_notifier(console_cpu_notify, 0);
+	ret = cpuhp_setup_state_nocalls(CPUHP_PRINTK_DEAD, "printk:dead", NULL,
+					console_cpu_notify);
+	WARN_ON(ret < 0);
+	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "printk:online",
+					console_cpu_notify, NULL);
+	WARN_ON(ret < 0);
 	return 0;
 }
 late_initcall(printk_late_init);

kernel/time/tick-sched.c

@@ -390,24 +390,16 @@ static int __init tick_nohz_full_setup(char *str)
 }
 __setup("nohz_full=", tick_nohz_full_setup);
 
-static int tick_nohz_cpu_down_callback(struct notifier_block *nfb,
-				       unsigned long action,
-				       void *hcpu)
+static int tick_nohz_cpu_down(unsigned int cpu)
 {
-	unsigned int cpu = (unsigned long)hcpu;
-
-	switch (action & ~CPU_TASKS_FROZEN) {
-	case CPU_DOWN_PREPARE:
-		/*
-		 * The boot CPU handles housekeeping duty (unbound timers,
-		 * workqueues, timekeeping, ...) on behalf of full dynticks
-		 * CPUs. It must remain online when nohz full is enabled.
-		 */
-		if (tick_nohz_full_running && tick_do_timer_cpu == cpu)
-			return NOTIFY_BAD;
-		break;
-	}
-	return NOTIFY_OK;
+	/*
+	 * The boot CPU handles housekeeping duty (unbound timers,
+	 * workqueues, timekeeping, ...) on behalf of full dynticks
+	 * CPUs. It must remain online when nohz full is enabled.
+	 */
+	if (tick_nohz_full_running && tick_do_timer_cpu == cpu)
+		return -EBUSY;
+	return 0;
 }
 
 static int tick_nohz_init_all(void)
@@ -428,7 +420,7 @@ static int tick_nohz_init_all(void)
 
 void __init tick_nohz_init(void)
 {
-	int cpu;
+	int cpu, ret;
 
 	if (!tick_nohz_full_running) {
 		if (tick_nohz_init_all() < 0)
@@ -469,7 +461,10 @@ void __init tick_nohz_init(void)
 	for_each_cpu(cpu, tick_nohz_full_mask)
 		context_tracking_cpu_set(cpu);
 
-	cpu_notifier(tick_nohz_cpu_down_callback, 0);
+	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
+					"kernel/nohz:predown", NULL,
+					tick_nohz_cpu_down);
+	WARN_ON(ret < 0);
 	pr_info("NO_HZ: Full dynticks CPUs: %*pbl.\n",
 		cpumask_pr_args(tick_nohz_full_mask));
 

kernel/trace/ring_buffer.c

@@ -479,9 +479,7 @@ struct ring_buffer {
 
 	struct ring_buffer_per_cpu	**buffers;
 
-#ifdef CONFIG_HOTPLUG_CPU
-	struct notifier_block		cpu_notify;
-#endif
+	struct hlist_node		node;
 	u64				(*clock)(void);
 
 	struct rb_irq_work		irq_work;
@@ -1274,11 +1272,6 @@ static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer)
 	kfree(cpu_buffer);
 }
 
-#ifdef CONFIG_HOTPLUG_CPU
-static int rb_cpu_notify(struct notifier_block *self,
-			 unsigned long action, void *hcpu);
-#endif
-
 /**
  * __ring_buffer_alloc - allocate a new ring_buffer
  * @size: the size in bytes per cpu that is needed.
@@ -1296,6 +1289,7 @@ struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
 	long nr_pages;
 	int bsize;
 	int cpu;
+	int ret;
 
 	/* keep it in its own cache line */
 	buffer = kzalloc(ALIGN(sizeof(*buffer), cache_line_size()),
@@ -1303,7 +1297,7 @@ struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
 	if (!buffer)
 		return NULL;
 
-	if (!alloc_cpumask_var(&buffer->cpumask, GFP_KERNEL))
+	if (!zalloc_cpumask_var(&buffer->cpumask, GFP_KERNEL))
 		goto fail_free_buffer;
 
 	nr_pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
@@ -1318,17 +1312,6 @@ struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
 	if (nr_pages < 2)
 		nr_pages = 2;
 
-	/*
-	 * In case of non-hotplug cpu, if the ring-buffer is allocated
-	 * in early initcall, it will not be notified of secondary cpus.
-	 * In that off case, we need to allocate for all possible cpus.
-	 */
-#ifdef CONFIG_HOTPLUG_CPU
-	cpu_notifier_register_begin();
-	cpumask_copy(buffer->cpumask, cpu_online_mask);
-#else
-	cpumask_copy(buffer->cpumask, cpu_possible_mask);
-#endif
 	buffer->cpus = nr_cpu_ids;
 
 	bsize = sizeof(void *) * nr_cpu_ids;
@@ -1337,19 +1320,15 @@ struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
 	if (!buffer->buffers)
 		goto fail_free_cpumask;
 
-	for_each_buffer_cpu(buffer, cpu) {
-		buffer->buffers[cpu] =
-			rb_allocate_cpu_buffer(buffer, nr_pages, cpu);
-		if (!buffer->buffers[cpu])
-			goto fail_free_buffers;
-	}
+	cpu = raw_smp_processor_id();
+	cpumask_set_cpu(cpu, buffer->cpumask);
+	buffer->buffers[cpu] = rb_allocate_cpu_buffer(buffer, nr_pages, cpu);
+	if (!buffer->buffers[cpu])
+		goto fail_free_buffers;
 
-#ifdef CONFIG_HOTPLUG_CPU
-	buffer->cpu_notify.notifier_call = rb_cpu_notify;
-	buffer->cpu_notify.priority = 0;
-	__register_cpu_notifier(&buffer->cpu_notify);
-	cpu_notifier_register_done();
-#endif
+	ret = cpuhp_state_add_instance(CPUHP_TRACE_RB_PREPARE, &buffer->node);
+	if (ret < 0)
+		goto fail_free_buffers;
 
 	mutex_init(&buffer->mutex);
 
@@ -1364,9 +1343,6 @@ struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
 
  fail_free_cpumask:
 	free_cpumask_var(buffer->cpumask);
-#ifdef CONFIG_HOTPLUG_CPU
-	cpu_notifier_register_done();
-#endif
 
  fail_free_buffer:
 	kfree(buffer);
@@ -1383,18 +1359,11 @@ ring_buffer_free(struct ring_buffer *buffer)
 {
 	int cpu;
 
-#ifdef CONFIG_HOTPLUG_CPU
-	cpu_notifier_register_begin();
-	__unregister_cpu_notifier(&buffer->cpu_notify);
-#endif
+	cpuhp_state_remove_instance(CPUHP_TRACE_RB_PREPARE, &buffer->node);
 
 	for_each_buffer_cpu(buffer, cpu)
 		rb_free_cpu_buffer(buffer->buffers[cpu]);
 
-#ifdef CONFIG_HOTPLUG_CPU
-	cpu_notifier_register_done();
-#endif
-
 	kfree(buffer->buffers);
 	free_cpumask_var(buffer->cpumask);
 
@@ -4633,62 +4602,48 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
 }
 EXPORT_SYMBOL_GPL(ring_buffer_read_page);
 
-#ifdef CONFIG_HOTPLUG_CPU
-static int rb_cpu_notify(struct notifier_block *self,
-			 unsigned long action, void *hcpu)
+/*
+ * We only allocate new buffers, never free them if the CPU goes down.
+ * If we were to free the buffer, then the user would lose any trace that was in
+ * the buffer.
+ */
+int trace_rb_cpu_prepare(unsigned int cpu, struct hlist_node *node)
 {
-	struct ring_buffer *buffer =
-		container_of(self, struct ring_buffer, cpu_notify);
-	long cpu = (long)hcpu;
+	struct ring_buffer *buffer;
 	long nr_pages_same;
 	int cpu_i;
 	unsigned long nr_pages;
 
-	switch (action) {
-	case CPU_UP_PREPARE:
-	case CPU_UP_PREPARE_FROZEN:
-		if (cpumask_test_cpu(cpu, buffer->cpumask))
-			return NOTIFY_OK;
-
-		nr_pages = 0;
-		nr_pages_same = 1;
-		/* check if all cpu sizes are same */
-		for_each_buffer_cpu(buffer, cpu_i) {
-			/* fill in the size from first enabled cpu */
-			if (nr_pages == 0)
-				nr_pages = buffer->buffers[cpu_i]->nr_pages;
-			if (nr_pages != buffer->buffers[cpu_i]->nr_pages) {
-				nr_pages_same = 0;
-				break;
-			}
-		}
-		/* allocate minimum pages, user can later expand it */
-		if (!nr_pages_same)
-			nr_pages = 2;
-		buffer->buffers[cpu] =
-			rb_allocate_cpu_buffer(buffer, nr_pages, cpu);
-		if (!buffer->buffers[cpu]) {
-			WARN(1, "failed to allocate ring buffer on CPU %ld\n",
-			     cpu);
-			return NOTIFY_OK;
+	buffer = container_of(node, struct ring_buffer, node);
+	if (cpumask_test_cpu(cpu, buffer->cpumask))
+		return 0;
+
+	nr_pages = 0;
+	nr_pages_same = 1;
+	/* check if all cpu sizes are same */
+	for_each_buffer_cpu(buffer, cpu_i) {
+		/* fill in the size from first enabled cpu */
+		if (nr_pages == 0)
+			nr_pages = buffer->buffers[cpu_i]->nr_pages;
+		if (nr_pages != buffer->buffers[cpu_i]->nr_pages) {
+			nr_pages_same = 0;
+			break;
 		}
-		smp_wmb();
-		cpumask_set_cpu(cpu, buffer->cpumask);
-		break;
-	case CPU_DOWN_PREPARE:
-	case CPU_DOWN_PREPARE_FROZEN:
-		/*
-		 * Do nothing.
-		 *  If we were to free the buffer, then the user would
-		 *  lose any trace that was in the buffer.
-		 */
-		break;
-	default:
-		break;
 	}
-	return NOTIFY_OK;
+	/* allocate minimum pages, user can later expand it */
+	if (!nr_pages_same)
+		nr_pages = 2;
+	buffer->buffers[cpu] =
+		rb_allocate_cpu_buffer(buffer, nr_pages, cpu);
+	if (!buffer->buffers[cpu]) {
+		WARN(1, "failed to allocate ring buffer on CPU %u\n",
+		     cpu);
+		return -ENOMEM;
+	}
+	smp_wmb();
+	cpumask_set_cpu(cpu, buffer->cpumask);
+	return 0;
 }
-#endif
 
 #ifdef CONFIG_RING_BUFFER_STARTUP_TEST
 /*

kernel/trace/trace.c

@@ -7659,10 +7659,21 @@ __init static int tracer_alloc_buffers(void)
 
 	raw_spin_lock_init(&global_trace.start_lock);
 
+	/*
+	 * The prepare callbacks allocates some memory for the ring buffer. We
+	 * don't free the buffer if the if the CPU goes down. If we were to free
+	 * the buffer, then the user would lose any trace that was in the
+	 * buffer. The memory will be removed once the "instance" is removed.
+	 */
+	ret = cpuhp_setup_state_multi(CPUHP_TRACE_RB_PREPARE,
+				      "trace/RB:preapre", trace_rb_cpu_prepare,
+				      NULL);
+	if (ret < 0)
+		goto out_free_cpumask;
 	/* Used for event triggers */
 	temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);
 	if (!temp_buffer)
-		goto out_free_cpumask;
+		goto out_rm_hp_state;
 
 	if (trace_create_savedcmd() < 0)
 		goto out_free_temp_buffer;
@@ -7723,6 +7734,8 @@ out_free_savedcmd:
 	free_saved_cmdlines_buffer(savedcmd);
 out_free_temp_buffer:
 	ring_buffer_free(temp_buffer);
+out_rm_hp_state:
+	cpuhp_remove_multi_state(CPUHP_TRACE_RB_PREPARE);
 out_free_cpumask:
 	free_cpumask_var(global_trace.tracing_cpumask);
 out_free_buffer_mask:

lib/percpu_counter.c

@@ -158,25 +158,21 @@ EXPORT_SYMBOL(percpu_counter_destroy);
 int percpu_counter_batch __read_mostly = 32;
 EXPORT_SYMBOL(percpu_counter_batch);
 
-static void compute_batch_value(void)
+static int compute_batch_value(unsigned int cpu)
 {
 	int nr = num_online_cpus();
 
 	percpu_counter_batch = max(32, nr*2);
+	return 0;
 }
 
-static int percpu_counter_hotcpu_callback(struct notifier_block *nb,
-					unsigned long action, void *hcpu)
+static int percpu_counter_cpu_dead(unsigned int cpu)
 {
 #ifdef CONFIG_HOTPLUG_CPU
-	unsigned int cpu;
 	struct percpu_counter *fbc;
 
-	compute_batch_value();
-	if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
-		return NOTIFY_OK;
+	compute_batch_value(cpu);
 
-	cpu = (unsigned long)hcpu;
 	spin_lock_irq(&percpu_counters_lock);
 	list_for_each_entry(fbc, &percpu_counters, list) {
 		s32 *pcount;
@@ -190,7 +186,7 @@ static int percpu_counter_hotcpu_callback(struct notifier_block *nb,
 	}
 	spin_unlock_irq(&percpu_counters_lock);
 #endif
-	return NOTIFY_OK;
+	return 0;
 }
 
 /*
@@ -222,8 +218,15 @@ EXPORT_SYMBOL(__percpu_counter_compare);
 
 static int __init percpu_counter_startup(void)
 {
-	compute_batch_value();
-	hotcpu_notifier(percpu_counter_hotcpu_callback, 0);
+	int ret;
+
+	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "lib/percpu_cnt:online",
+				compute_batch_value, NULL);
+	WARN_ON(ret < 0);
+	ret = cpuhp_setup_state_nocalls(CPUHP_PERCPU_CNT_DEAD,
+					"lib/percpu_cnt:dead", NULL,
+					percpu_counter_cpu_dead);
+	WARN_ON(ret < 0);
 	return 0;
 }
 module_init(percpu_counter_startup);

lib/radix-tree.c

@@ -1642,32 +1642,31 @@ static __init void radix_tree_init_maxnodes(void)
 	}
 }
 
-static int radix_tree_callback(struct notifier_block *nfb,
-				unsigned long action, void *hcpu)
+static int radix_tree_cpu_dead(unsigned int cpu)
 {
-	int cpu = (long)hcpu;
 	struct radix_tree_preload *rtp;
 	struct radix_tree_node *node;
 
 	/* Free per-cpu pool of preloaded nodes */
-	if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
-		rtp = &per_cpu(radix_tree_preloads, cpu);
-		while (rtp->nr) {
-			node = rtp->nodes;
-			rtp->nodes = node->private_data;
-			kmem_cache_free(radix_tree_node_cachep, node);
-			rtp->nr--;
-		}
+	rtp = &per_cpu(radix_tree_preloads, cpu);
+	while (rtp->nr) {
+		node = rtp->nodes;
+		rtp->nodes = node->private_data;
+		kmem_cache_free(radix_tree_node_cachep, node);
+		rtp->nr--;
 	}
-	return NOTIFY_OK;
+	return 0;
 }
 
 void __init radix_tree_init(void)
 {
+	int ret;
 	radix_tree_node_cachep = kmem_cache_create("radix_tree_node",
 			sizeof(struct radix_tree_node), 0,
 			SLAB_PANIC | SLAB_RECLAIM_ACCOUNT,
 			radix_tree_node_ctor);
 	radix_tree_init_maxnodes();
-	hotcpu_notifier(radix_tree_callback, 0);
+	ret = cpuhp_setup_state_nocalls(CPUHP_RADIX_DEAD, "lib/radix:dead",
+					NULL, radix_tree_cpu_dead);
+	WARN_ON(ret < 0);
 }

mm/compaction.c

@@ -2043,33 +2043,38 @@ void kcompactd_stop(int nid)
  * away, we get changed to run anywhere: as the first one comes back,
  * restore their cpu bindings.
  */
-static int cpu_callback(struct notifier_block *nfb, unsigned long action,
-			void *hcpu)
+static int kcompactd_cpu_online(unsigned int cpu)
 {
 	int nid;
 
-	if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN) {
-		for_each_node_state(nid, N_MEMORY) {
-			pg_data_t *pgdat = NODE_DATA(nid);
-			const struct cpumask *mask;
+	for_each_node_state(nid, N_MEMORY) {
+		pg_data_t *pgdat = NODE_DATA(nid);
+		const struct cpumask *mask;
 
-			mask = cpumask_of_node(pgdat->node_id);
+		mask = cpumask_of_node(pgdat->node_id);
 
-			if (cpumask_any_and(cpu_online_mask, mask) < nr_cpu_ids)
-				/* One of our CPUs online: restore mask */
-				set_cpus_allowed_ptr(pgdat->kcompactd, mask);
-		}
+		if (cpumask_any_and(cpu_online_mask, mask) < nr_cpu_ids)
+			/* One of our CPUs online: restore mask */
+			set_cpus_allowed_ptr(pgdat->kcompactd, mask);
 	}
-	return NOTIFY_OK;
+	return 0;
 }
 
 static int __init kcompactd_init(void)
 {
 	int nid;
+	int ret;
+
+	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
+					"mm/compaction:online",
+					kcompactd_cpu_online, NULL);
+	if (ret < 0) {
+		pr_err("kcompactd: failed to register hotplug callbacks.\n");
+		return ret;
+	}
 
 	for_each_node_state(nid, N_MEMORY)
 		kcompactd_run(nid);
-	hotcpu_notifier(cpu_callback, 0);
 	return 0;
 }
 subsys_initcall(kcompactd_init)

mm/memcontrol.c

@@ -1816,22 +1816,13 @@ static void drain_all_stock(struct mem_cgroup *root_memcg)
 	mutex_unlock(&percpu_charge_mutex);
 }
 
-static int memcg_cpu_hotplug_callback(struct notifier_block *nb,
-					unsigned long action,
-					void *hcpu)
+static int memcg_hotplug_cpu_dead(unsigned int cpu)
 {
-	int cpu = (unsigned long)hcpu;
 	struct memcg_stock_pcp *stock;
 
-	if (action == CPU_ONLINE)
-		return NOTIFY_OK;
-
-	if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
-		return NOTIFY_OK;
-
 	stock = &per_cpu(memcg_stock, cpu);
 	drain_stock(stock);
-	return NOTIFY_OK;
+	return 0;
 }
 
 static void reclaim_high(struct mem_cgroup *memcg,
@@ -5774,16 +5765,17 @@ __setup("cgroup.memory=", cgroup_memory);
 /*
  * subsys_initcall() for memory controller.
  *
- * Some parts like hotcpu_notifier() have to be initialized from this context
- * because of lock dependencies (cgroup_lock -> cpu hotplug) but basically
- * everything that doesn't depend on a specific mem_cgroup structure should
- * be initialized from here.
+ * Some parts like memcg_hotplug_cpu_dead() have to be initialized from this
+ * context because of lock dependencies (cgroup_lock -> cpu hotplug) but
+ * basically everything that doesn't depend on a specific mem_cgroup structure
+ * should be initialized from here.
  */
 static int __init mem_cgroup_init(void)
 {
 	int cpu, node;
 
-	hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
+	cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD, "mm/memctrl:dead", NULL,
+				  memcg_hotplug_cpu_dead);
 
 	for_each_possible_cpu(cpu)
 		INIT_WORK(&per_cpu_ptr(&memcg_stock, cpu)->work,

mm/page_alloc.c

@@ -6491,38 +6491,39 @@ void __init free_area_init(unsigned long *zones_size)
 			__pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
 }
 
-static int page_alloc_cpu_notify(struct notifier_block *self,
-				 unsigned long action, void *hcpu)
+static int page_alloc_cpu_dead(unsigned int cpu)
 {
-	int cpu = (unsigned long)hcpu;
 
-	if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
-		lru_add_drain_cpu(cpu);
-		drain_pages(cpu);
+	lru_add_drain_cpu(cpu);
+	drain_pages(cpu);
 
-		/*
-		 * Spill the event counters of the dead processor
-		 * into the current processors event counters.
-		 * This artificially elevates the count of the current
-		 * processor.
-		 */
-		vm_events_fold_cpu(cpu);
+	/*
+	 * Spill the event counters of the dead processor
+	 * into the current processors event counters.
+	 * This artificially elevates the count of the current
+	 * processor.
+	 */
+	vm_events_fold_cpu(cpu);
 
-		/*
-		 * Zero the differential counters of the dead processor
-		 * so that the vm statistics are consistent.
-		 *
-		 * This is only okay since the processor is dead and cannot
-		 * race with what we are doing.
-		 */
-		cpu_vm_stats_fold(cpu);
-	}
-	return NOTIFY_OK;
+	/*
+	 * Zero the differential counters of the dead processor
+	 * so that the vm statistics are consistent.
+	 *
+	 * This is only okay since the processor is dead and cannot
+	 * race with what we are doing.
+	 */
+	cpu_vm_stats_fold(cpu);
+	return 0;
 }
 
 void __init page_alloc_init(void)
 {
-	hotcpu_notifier(page_alloc_cpu_notify, 0);
+	int ret;
+
+	ret = cpuhp_setup_state_nocalls(CPUHP_PAGE_ALLOC_DEAD,
+					"mm/page_alloc:dead", NULL,
+					page_alloc_cpu_dead);
+	WARN_ON(ret < 0);
 }
 
 /*

mm/vmscan.c

@@ -3558,24 +3558,21 @@ unsigned long shrink_all_memory(unsigned long nr_to_reclaim)
    not required for correctness.  So if the last cpu in a node goes
    away, we get changed to run anywhere: as the first one comes back,
    restore their cpu bindings. */
-static int cpu_callback(struct notifier_block *nfb, unsigned long action,
-			void *hcpu)
+static int kswapd_cpu_online(unsigned int cpu)
 {
 	int nid;
 
-	if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN) {
-		for_each_node_state(nid, N_MEMORY) {
-			pg_data_t *pgdat = NODE_DATA(nid);
-			const struct cpumask *mask;
+	for_each_node_state(nid, N_MEMORY) {
+		pg_data_t *pgdat = NODE_DATA(nid);
+		const struct cpumask *mask;
 
-			mask = cpumask_of_node(pgdat->node_id);
+		mask = cpumask_of_node(pgdat->node_id);
 
-			if (cpumask_any_and(cpu_online_mask, mask) < nr_cpu_ids)
-				/* One of our CPUs online: restore mask */
-				set_cpus_allowed_ptr(pgdat->kswapd, mask);
-		}
+		if (cpumask_any_and(cpu_online_mask, mask) < nr_cpu_ids)
+			/* One of our CPUs online: restore mask */
+			set_cpus_allowed_ptr(pgdat->kswapd, mask);
 	}
-	return NOTIFY_OK;
+	return 0;
 }
 
 /*
@@ -3617,12 +3614,15 @@ void kswapd_stop(int nid)
 
 static int __init kswapd_init(void)
 {
-	int nid;
+	int nid, ret;
 
 	swap_setup();
 	for_each_node_state(nid, N_MEMORY)
  		kswapd_run(nid);
-	hotcpu_notifier(cpu_callback, 0);
+	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
+					"mm/vmscan:online", kswapd_cpu_online,
+					NULL);
+	WARN_ON(ret < 0);
 	return 0;
 }
 

mm/vmstat.c

@@ -1720,75 +1720,66 @@ static void __init start_shepherd_timer(void)
 
 static void __init init_cpu_node_state(void)
 {
-	int cpu;
+	int node;
 
-	get_online_cpus();
-	for_each_online_cpu(cpu)
-		node_set_state(cpu_to_node(cpu), N_CPU);
-	put_online_cpus();
+	for_each_online_node(node) {
+		if (cpumask_weight(cpumask_of_node(node)) > 0)
+			node_set_state(node, N_CPU);
+	}
 }
 
-static void vmstat_cpu_dead(int node)
+static int vmstat_cpu_online(unsigned int cpu)
 {
-	int cpu;
-
-	get_online_cpus();
-	for_each_online_cpu(cpu)
-		if (cpu_to_node(cpu) == node)
-			goto end;
+	refresh_zone_stat_thresholds();
+	node_set_state(cpu_to_node(cpu), N_CPU);
+	return 0;
+}
 
-	node_clear_state(node, N_CPU);
-end:
-	put_online_cpus();
+static int vmstat_cpu_down_prep(unsigned int cpu)
+{
+	cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
+	return 0;
 }
 
-/*
- * Use the cpu notifier to insure that the thresholds are recalculated
- * when necessary.
- */
-static int vmstat_cpuup_callback(struct notifier_block *nfb,
-		unsigned long action,
-		void *hcpu)
-{
-	long cpu = (long)hcpu;
-
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-		refresh_zone_stat_thresholds();
-		node_set_state(cpu_to_node(cpu), N_CPU);
-		break;
-	case CPU_DOWN_PREPARE:
-	case CPU_DOWN_PREPARE_FROZEN:
-		cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
-		break;
-	case CPU_DOWN_FAILED:
-	case CPU_DOWN_FAILED_FROZEN:
-		break;
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		refresh_zone_stat_thresholds();
-		vmstat_cpu_dead(cpu_to_node(cpu));
-		break;
-	default:
-		break;
-	}
-	return NOTIFY_OK;
+static int vmstat_cpu_dead(unsigned int cpu)
+{
+	const struct cpumask *node_cpus;
+	int node;
+
+	node = cpu_to_node(cpu);
+
+	refresh_zone_stat_thresholds();
+	node_cpus = cpumask_of_node(node);
+	if (cpumask_weight(node_cpus) > 0)
+		return 0;
+
+	node_clear_state(node, N_CPU);
+	return 0;
 }
 
-static struct notifier_block vmstat_notifier =
-	{ &vmstat_cpuup_callback, NULL, 0 };
 #endif
 
 static int __init setup_vmstat(void)
 {
 #ifdef CONFIG_SMP
-	cpu_notifier_register_begin();
-	__register_cpu_notifier(&vmstat_notifier);
+	int ret;
+
+	ret = cpuhp_setup_state_nocalls(CPUHP_MM_VMSTAT_DEAD, "mm/vmstat:dead",
+					NULL, vmstat_cpu_dead);
+	if (ret < 0)
+		pr_err("vmstat: failed to register 'dead' hotplug state\n");
+
+	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "mm/vmstat:online",
+					vmstat_cpu_online,
+					vmstat_cpu_down_prep);
+	if (ret < 0)
+		pr_err("vmstat: failed to register 'online' hotplug state\n");
+
+	get_online_cpus();
 	init_cpu_node_state();
+	put_online_cpus();
 
 	start_shepherd_timer();
-	cpu_notifier_register_done();
 #endif
 #ifdef CONFIG_PROC_FS
 	proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations);

mm/zsmalloc.c

@@ -1284,61 +1284,21 @@ out:
 
 #endif /* CONFIG_PGTABLE_MAPPING */
 
-static int zs_cpu_notifier(struct notifier_block *nb, unsigned long action,
-				void *pcpu)
+static int zs_cpu_prepare(unsigned int cpu)
 {
-	int ret, cpu = (long)pcpu;
 	struct mapping_area *area;
 
-	switch (action) {
-	case CPU_UP_PREPARE:
-		area = &per_cpu(zs_map_area, cpu);
-		ret = __zs_cpu_up(area);
-		if (ret)
-			return notifier_from_errno(ret);
-		break;
-	case CPU_DEAD:
-	case CPU_UP_CANCELED:
-		area = &per_cpu(zs_map_area, cpu);
-		__zs_cpu_down(area);
-		break;
-	}
-
-	return NOTIFY_OK;
+	area = &per_cpu(zs_map_area, cpu);
+	return __zs_cpu_up(area);
 }
 
-static struct notifier_block zs_cpu_nb = {
-	.notifier_call = zs_cpu_notifier
-};
-
-static int zs_register_cpu_notifier(void)
+static int zs_cpu_dead(unsigned int cpu)
 {
-	int cpu, uninitialized_var(ret);
-
-	cpu_notifier_register_begin();
-
-	__register_cpu_notifier(&zs_cpu_nb);
-	for_each_online_cpu(cpu) {
-		ret = zs_cpu_notifier(NULL, CPU_UP_PREPARE, (void *)(long)cpu);
-		if (notifier_to_errno(ret))
-			break;
-	}
-
-	cpu_notifier_register_done();
-	return notifier_to_errno(ret);
-}
-
-static void zs_unregister_cpu_notifier(void)
-{
-	int cpu;
-
-	cpu_notifier_register_begin();
-
-	for_each_online_cpu(cpu)
-		zs_cpu_notifier(NULL, CPU_DEAD, (void *)(long)cpu);
-	__unregister_cpu_notifier(&zs_cpu_nb);
+	struct mapping_area *area;
 
-	cpu_notifier_register_done();
+	area = &per_cpu(zs_map_area, cpu);
+	__zs_cpu_down(area);
+	return 0;
 }
 
 static void __init init_zs_size_classes(void)
@@ -2534,10 +2494,10 @@ static int __init zs_init(void)
 	if (ret)
 		goto out;
 
-	ret = zs_register_cpu_notifier();
-
+	ret = cpuhp_setup_state(CPUHP_MM_ZS_PREPARE, "mm/zsmalloc:prepare",
+				zs_cpu_prepare, zs_cpu_dead);
 	if (ret)
-		goto notifier_fail;
+		goto hp_setup_fail;
 
 	init_zs_size_classes();
 
@@ -2549,8 +2509,7 @@ static int __init zs_init(void)
 
 	return 0;
 
-notifier_fail:
-	zs_unregister_cpu_notifier();
+hp_setup_fail:
 	zsmalloc_unmount();
 out:
 	return ret;
@@ -2562,7 +2521,7 @@ static void __exit zs_exit(void)
 	zpool_unregister_driver(&zs_zpool_driver);
 #endif
 	zsmalloc_unmount();
-	zs_unregister_cpu_notifier();
+	cpuhp_remove_state(CPUHP_MM_ZS_PREPARE);
 
 	zs_stat_exit();
 }

mm/zswap.c

@@ -118,7 +118,7 @@ struct zswap_pool {
 	struct kref kref;
 	struct list_head list;
 	struct work_struct work;
-	struct notifier_block notifier;
+	struct hlist_node node;
 	char tfm_name[CRYPTO_MAX_ALG_NAME];
 };
 
@@ -352,143 +352,58 @@ static struct zswap_entry *zswap_entry_find_get(struct rb_root *root,
 **********************************/
 static DEFINE_PER_CPU(u8 *, zswap_dstmem);
 
-static int __zswap_cpu_dstmem_notifier(unsigned long action, unsigned long cpu)
+static int zswap_dstmem_prepare(unsigned int cpu)
 {
 	u8 *dst;
 
-	switch (action) {
-	case CPU_UP_PREPARE:
-		dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
-		if (!dst) {
-			pr_err("can't allocate compressor buffer\n");
-			return NOTIFY_BAD;
-		}
-		per_cpu(zswap_dstmem, cpu) = dst;
-		break;
-	case CPU_DEAD:
-	case CPU_UP_CANCELED:
-		dst = per_cpu(zswap_dstmem, cpu);
-		kfree(dst);
-		per_cpu(zswap_dstmem, cpu) = NULL;
-		break;
-	default:
-		break;
+	dst = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu));
+	if (!dst) {
+		pr_err("can't allocate compressor buffer\n");
+		return -ENOMEM;
 	}
-	return NOTIFY_OK;
+	per_cpu(zswap_dstmem, cpu) = dst;
+	return 0;
 }
 
-static int zswap_cpu_dstmem_notifier(struct notifier_block *nb,
-				     unsigned long action, void *pcpu)
+static int zswap_dstmem_dead(unsigned int cpu)
 {
-	return __zswap_cpu_dstmem_notifier(action, (unsigned long)pcpu);
-}
+	u8 *dst;
 
-static struct notifier_block zswap_dstmem_notifier = {
-	.notifier_call =	zswap_cpu_dstmem_notifier,
-};
+	dst = per_cpu(zswap_dstmem, cpu);
+	kfree(dst);
+	per_cpu(zswap_dstmem, cpu) = NULL;
 
-static int __init zswap_cpu_dstmem_init(void)
-{
-	unsigned long cpu;
-
-	cpu_notifier_register_begin();
-	for_each_online_cpu(cpu)
-		if (__zswap_cpu_dstmem_notifier(CPU_UP_PREPARE, cpu) ==
-		    NOTIFY_BAD)
-			goto cleanup;
-	__register_cpu_notifier(&zswap_dstmem_notifier);
-	cpu_notifier_register_done();
 	return 0;
-
-cleanup:
-	for_each_online_cpu(cpu)
-		__zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
-	cpu_notifier_register_done();
-	return -ENOMEM;
-}
-
-static void zswap_cpu_dstmem_destroy(void)
-{
-	unsigned long cpu;
-
-	cpu_notifier_register_begin();
-	for_each_online_cpu(cpu)
-		__zswap_cpu_dstmem_notifier(CPU_UP_CANCELED, cpu);
-	__unregister_cpu_notifier(&zswap_dstmem_notifier);
-	cpu_notifier_register_done();
 }
 
-static int __zswap_cpu_comp_notifier(struct zswap_pool *pool,
-				     unsigned long action, unsigned long cpu)
+static int zswap_cpu_comp_prepare(unsigned int cpu, struct hlist_node *node)
 {
+	struct zswap_pool *pool = hlist_entry(node, struct zswap_pool, node);
 	struct crypto_comp *tfm;
 
-	switch (action) {
-	case CPU_UP_PREPARE:
-		if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
-			break;
-		tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
-		if (IS_ERR_OR_NULL(tfm)) {
-			pr_err("could not alloc crypto comp %s : %ld\n",
-			       pool->tfm_name, PTR_ERR(tfm));
-			return NOTIFY_BAD;
-		}
-		*per_cpu_ptr(pool->tfm, cpu) = tfm;
-		break;
-	case CPU_DEAD:
-	case CPU_UP_CANCELED:
-		tfm = *per_cpu_ptr(pool->tfm, cpu);
-		if (!IS_ERR_OR_NULL(tfm))
-			crypto_free_comp(tfm);
-		*per_cpu_ptr(pool->tfm, cpu) = NULL;
-		break;
-	default:
-		break;
-	}
-	return NOTIFY_OK;
-}
-
-static int zswap_cpu_comp_notifier(struct notifier_block *nb,
-				   unsigned long action, void *pcpu)
-{
-	unsigned long cpu = (unsigned long)pcpu;
-	struct zswap_pool *pool = container_of(nb, typeof(*pool), notifier);
-
-	return __zswap_cpu_comp_notifier(pool, action, cpu);
-}
+	if (WARN_ON(*per_cpu_ptr(pool->tfm, cpu)))
+		return 0;
 
-static int zswap_cpu_comp_init(struct zswap_pool *pool)
-{
-	unsigned long cpu;
-
-	memset(&pool->notifier, 0, sizeof(pool->notifier));
-	pool->notifier.notifier_call = zswap_cpu_comp_notifier;
-
-	cpu_notifier_register_begin();
-	for_each_online_cpu(cpu)
-		if (__zswap_cpu_comp_notifier(pool, CPU_UP_PREPARE, cpu) ==
-		    NOTIFY_BAD)
-			goto cleanup;
-	__register_cpu_notifier(&pool->notifier);
-	cpu_notifier_register_done();
+	tfm = crypto_alloc_comp(pool->tfm_name, 0, 0);
+	if (IS_ERR_OR_NULL(tfm)) {
+		pr_err("could not alloc crypto comp %s : %ld\n",
+		       pool->tfm_name, PTR_ERR(tfm));
+		return -ENOMEM;
+	}
+	*per_cpu_ptr(pool->tfm, cpu) = tfm;
 	return 0;
-
-cleanup:
-	for_each_online_cpu(cpu)
-		__zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
-	cpu_notifier_register_done();
-	return -ENOMEM;
 }
 
-static void zswap_cpu_comp_destroy(struct zswap_pool *pool)
+static int zswap_cpu_comp_dead(unsigned int cpu, struct hlist_node *node)
 {
-	unsigned long cpu;
+	struct zswap_pool *pool = hlist_entry(node, struct zswap_pool, node);
+	struct crypto_comp *tfm;
 
-	cpu_notifier_register_begin();
-	for_each_online_cpu(cpu)
-		__zswap_cpu_comp_notifier(pool, CPU_UP_CANCELED, cpu);
-	__unregister_cpu_notifier(&pool->notifier);
-	cpu_notifier_register_done();
+	tfm = *per_cpu_ptr(pool->tfm, cpu);
+	if (!IS_ERR_OR_NULL(tfm))
+		crypto_free_comp(tfm);
+	*per_cpu_ptr(pool->tfm, cpu) = NULL;
+	return 0;
 }
 
 /*********************************
@@ -569,6 +484,7 @@ static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
 	struct zswap_pool *pool;
 	char name[38]; /* 'zswap' + 32 char (max) num + \0 */
 	gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM;
+	int ret;
 
 	pool = kzalloc(sizeof(*pool), GFP_KERNEL);
 	if (!pool) {
@@ -593,7 +509,9 @@ static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
 		goto error;
 	}
 
-	if (zswap_cpu_comp_init(pool))
+	ret = cpuhp_state_add_instance(CPUHP_MM_ZSWP_POOL_PREPARE,
+				       &pool->node);
+	if (ret)
 		goto error;
 	pr_debug("using %s compressor\n", pool->tfm_name);
 
@@ -647,7 +565,7 @@ static void zswap_pool_destroy(struct zswap_pool *pool)
 {
 	zswap_pool_debug("destroying", pool);
 
-	zswap_cpu_comp_destroy(pool);
+	cpuhp_state_remove_instance(CPUHP_MM_ZSWP_POOL_PREPARE, &pool->node);
 	free_percpu(pool->tfm);
 	zpool_destroy_pool(pool->zpool);
 	kfree(pool);
@@ -1238,6 +1156,7 @@ static void __exit zswap_debugfs_exit(void) { }
 static int __init init_zswap(void)
 {
 	struct zswap_pool *pool;
+	int ret;
 
 	zswap_init_started = true;
 
@@ -1246,11 +1165,20 @@ static int __init init_zswap(void)
 		goto cache_fail;
 	}
 
-	if (zswap_cpu_dstmem_init()) {
+	ret = cpuhp_setup_state(CPUHP_MM_ZSWP_MEM_PREPARE, "mm/zswap:prepare",
+				zswap_dstmem_prepare, zswap_dstmem_dead);
+	if (ret) {
 		pr_err("dstmem alloc failed\n");
 		goto dstmem_fail;
 	}
 
+	ret = cpuhp_setup_state_multi(CPUHP_MM_ZSWP_POOL_PREPARE,
+				      "mm/zswap_pool:prepare",
+				      zswap_cpu_comp_prepare,
+				      zswap_cpu_comp_dead);
+	if (ret)
+		goto hp_fail;
+
 	pool = __zswap_pool_create_fallback();
 	if (!pool) {
 		pr_err("pool creation failed\n");
@@ -1267,7 +1195,9 @@ static int __init init_zswap(void)
 	return 0;
 
 pool_fail:
-	zswap_cpu_dstmem_destroy();
+	cpuhp_remove_state_nocalls(CPUHP_MM_ZSWP_POOL_PREPARE);
+hp_fail:
+	cpuhp_remove_state(CPUHP_MM_ZSWP_MEM_PREPARE);
 dstmem_fail:
 	zswap_entry_cache_destroy();
 cache_fail:

net/core/dev.c

@@ -8008,18 +8008,13 @@ out:
 }
 EXPORT_SYMBOL_GPL(dev_change_net_namespace);
 
-static int dev_cpu_callback(struct notifier_block *nfb,
-			    unsigned long action,
-			    void *ocpu)
+static int dev_cpu_dead(unsigned int oldcpu)
 {
 	struct sk_buff **list_skb;
 	struct sk_buff *skb;
-	unsigned int cpu, oldcpu = (unsigned long)ocpu;
+	unsigned int cpu;
 	struct softnet_data *sd, *oldsd;
 
-	if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
-		return NOTIFY_OK;
-
 	local_irq_disable();
 	cpu = smp_processor_id();
 	sd = &per_cpu(softnet_data, cpu);
@@ -8069,10 +8064,9 @@ static int dev_cpu_callback(struct notifier_block *nfb,
 		input_queue_head_incr(oldsd);
 	}
 
-	return NOTIFY_OK;
+	return 0;
 }
 
-
 /**
  *	netdev_increment_features - increment feature set by one
  *	@all: current feature set
@@ -8406,7 +8400,9 @@ static int __init net_dev_init(void)
 	open_softirq(NET_TX_SOFTIRQ, net_tx_action);
 	open_softirq(NET_RX_SOFTIRQ, net_rx_action);
 
-	hotcpu_notifier(dev_cpu_callback, 0);
+	rc = cpuhp_setup_state_nocalls(CPUHP_NET_DEV_DEAD, "net/dev:dead",
+				       NULL, dev_cpu_dead);
+	WARN_ON(rc < 0);
 	dst_subsys_init();
 	rc = 0;
 out:

net/core/flow.c

@@ -417,28 +417,20 @@ static int flow_cache_cpu_prepare(struct flow_cache *fc, int cpu)
 	return 0;
 }
 
-static int flow_cache_cpu(struct notifier_block *nfb,
-			  unsigned long action,
-			  void *hcpu)
+static int flow_cache_cpu_up_prep(unsigned int cpu, struct hlist_node *node)
 {
-	struct flow_cache *fc = container_of(nfb, struct flow_cache,
-						hotcpu_notifier);
-	int res, cpu = (unsigned long) hcpu;
+	struct flow_cache *fc = hlist_entry_safe(node, struct flow_cache, node);
+
+	return flow_cache_cpu_prepare(fc, cpu);
+}
+
+static int flow_cache_cpu_dead(unsigned int cpu, struct hlist_node *node)
+{
+	struct flow_cache *fc = hlist_entry_safe(node, struct flow_cache, node);
 	struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);
 
-	switch (action) {
-	case CPU_UP_PREPARE:
-	case CPU_UP_PREPARE_FROZEN:
-		res = flow_cache_cpu_prepare(fc, cpu);
-		if (res)
-			return notifier_from_errno(res);
-		break;
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		__flow_cache_shrink(fc, fcp, 0);
-		break;
-	}
-	return NOTIFY_OK;
+	__flow_cache_shrink(fc, fcp, 0);
+	return 0;
 }
 
 int flow_cache_init(struct net *net)
@@ -465,18 +457,8 @@ int flow_cache_init(struct net *net)
 	if (!fc->percpu)
 		return -ENOMEM;
 
-	cpu_notifier_register_begin();
-
-	for_each_online_cpu(i) {
-		if (flow_cache_cpu_prepare(fc, i))
-			goto err;
-	}
-	fc->hotcpu_notifier = (struct notifier_block){
-		.notifier_call = flow_cache_cpu,
-	};
-	__register_hotcpu_notifier(&fc->hotcpu_notifier);
-
-	cpu_notifier_register_done();
+	if (cpuhp_state_add_instance(CPUHP_NET_FLOW_PREPARE, &fc->node))
+		goto err;
 
 	setup_timer(&fc->rnd_timer, flow_cache_new_hashrnd,
 		    (unsigned long) fc);
@@ -492,8 +474,6 @@ err:
 		fcp->hash_table = NULL;
 	}
 
-	cpu_notifier_register_done();
-
 	free_percpu(fc->percpu);
 	fc->percpu = NULL;
 
@@ -507,7 +487,8 @@ void flow_cache_fini(struct net *net)
 	struct flow_cache *fc = &net->xfrm.flow_cache_global;
 
 	del_timer_sync(&fc->rnd_timer);
-	unregister_hotcpu_notifier(&fc->hotcpu_notifier);
+
+	cpuhp_state_remove_instance_nocalls(CPUHP_NET_FLOW_PREPARE, &fc->node);
 
 	for_each_possible_cpu(i) {
 		struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, i);
@@ -519,3 +500,14 @@ void flow_cache_fini(struct net *net)
 	fc->percpu = NULL;
 }
 EXPORT_SYMBOL(flow_cache_fini);
+
+void __init flow_cache_hp_init(void)
+{
+	int ret;
+
+	ret = cpuhp_setup_state_multi(CPUHP_NET_FLOW_PREPARE,
+				      "net/flow:prepare",
+				      flow_cache_cpu_up_prep,
+				      flow_cache_cpu_dead);
+	WARN_ON(ret < 0);
+}

net/iucv/iucv.c

@@ -639,7 +639,7 @@ static void iucv_disable(void)
 	put_online_cpus();
 }
 
-static void free_iucv_data(int cpu)
+static int iucv_cpu_dead(unsigned int cpu)
 {
 	kfree(iucv_param_irq[cpu]);
 	iucv_param_irq[cpu] = NULL;
@@ -647,9 +647,10 @@ static void free_iucv_data(int cpu)
 	iucv_param[cpu] = NULL;
 	kfree(iucv_irq_data[cpu]);
 	iucv_irq_data[cpu] = NULL;
+	return 0;
 }
 
-static int alloc_iucv_data(int cpu)
+static int iucv_cpu_prepare(unsigned int cpu)
 {
 	/* Note: GFP_DMA used to get memory below 2G */
 	iucv_irq_data[cpu] = kmalloc_node(sizeof(struct iucv_irq_data),
@@ -671,58 +672,38 @@ static int alloc_iucv_data(int cpu)
 	return 0;
 
 out_free:
-	free_iucv_data(cpu);
+	iucv_cpu_dead(cpu);
 	return -ENOMEM;
 }
 
-static int iucv_cpu_notify(struct notifier_block *self,
-				     unsigned long action, void *hcpu)
+static int iucv_cpu_online(unsigned int cpu)
 {
-	cpumask_t cpumask;
-	long cpu = (long) hcpu;
-
-	switch (action) {
-	case CPU_UP_PREPARE:
-	case CPU_UP_PREPARE_FROZEN:
-		if (alloc_iucv_data(cpu))
-			return notifier_from_errno(-ENOMEM);
-		break;
-	case CPU_UP_CANCELED:
-	case CPU_UP_CANCELED_FROZEN:
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		free_iucv_data(cpu);
-		break;
-	case CPU_ONLINE:
-	case CPU_ONLINE_FROZEN:
-	case CPU_DOWN_FAILED:
-	case CPU_DOWN_FAILED_FROZEN:
-		if (!iucv_path_table)
-			break;
-		smp_call_function_single(cpu, iucv_declare_cpu, NULL, 1);
-		break;
-	case CPU_DOWN_PREPARE:
-	case CPU_DOWN_PREPARE_FROZEN:
-		if (!iucv_path_table)
-			break;
-		cpumask_copy(&cpumask, &iucv_buffer_cpumask);
-		cpumask_clear_cpu(cpu, &cpumask);
-		if (cpumask_empty(&cpumask))
-			/* Can't offline last IUCV enabled cpu. */
-			return notifier_from_errno(-EINVAL);
-		smp_call_function_single(cpu, iucv_retrieve_cpu, NULL, 1);
-		if (cpumask_empty(&iucv_irq_cpumask))
-			smp_call_function_single(
-				cpumask_first(&iucv_buffer_cpumask),
-				iucv_allow_cpu, NULL, 1);
-		break;
-	}
-	return NOTIFY_OK;
+	if (!iucv_path_table)
+		return 0;
+	iucv_declare_cpu(NULL);
+	return 0;
 }
 
-static struct notifier_block __refdata iucv_cpu_notifier = {
-	.notifier_call = iucv_cpu_notify,
-};
+static int iucv_cpu_down_prep(unsigned int cpu)
+{
+	cpumask_t cpumask;
+
+	if (!iucv_path_table)
+		return 0;
+
+	cpumask_copy(&cpumask, &iucv_buffer_cpumask);
+	cpumask_clear_cpu(cpu, &cpumask);
+	if (cpumask_empty(&cpumask))
+		/* Can't offline last IUCV enabled cpu. */
+		return -EINVAL;
+
+	iucv_retrieve_cpu(NULL);
+	if (!cpumask_empty(&iucv_irq_cpumask))
+		return 0;
+	smp_call_function_single(cpumask_first(&iucv_buffer_cpumask),
+				 iucv_allow_cpu, NULL, 1);
+	return 0;
+}
 
 /**
  * iucv_sever_pathid
@@ -2027,6 +2008,7 @@ struct iucv_interface iucv_if = {
 };
 EXPORT_SYMBOL(iucv_if);
 
+static enum cpuhp_state iucv_online;
 /**
  * iucv_init
  *
@@ -2035,7 +2017,6 @@ EXPORT_SYMBOL(iucv_if);
 static int __init iucv_init(void)
 {
 	int rc;
-	int cpu;
 
 	if (!MACHINE_IS_VM) {
 		rc = -EPROTONOSUPPORT;
@@ -2054,23 +2035,19 @@ static int __init iucv_init(void)
 		goto out_int;
 	}
 
-	cpu_notifier_register_begin();
-
-	for_each_online_cpu(cpu) {
-		if (alloc_iucv_data(cpu)) {
-			rc = -ENOMEM;
-			goto out_free;
-		}
-	}
-	rc = __register_hotcpu_notifier(&iucv_cpu_notifier);
+	rc = cpuhp_setup_state(CPUHP_NET_IUCV_PREPARE, "net/iucv:prepare",
+			       iucv_cpu_prepare, iucv_cpu_dead);
 	if (rc)
-		goto out_free;
-
-	cpu_notifier_register_done();
+		goto out_dev;
+	rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "net/iucv:online",
+			       iucv_cpu_online, iucv_cpu_down_prep);
+	if (rc < 0)
+		goto out_prep;
+	iucv_online = rc;
 
 	rc = register_reboot_notifier(&iucv_reboot_notifier);
 	if (rc)
-		goto out_cpu;
+		goto out_remove_hp;
 	ASCEBC(iucv_error_no_listener, 16);
 	ASCEBC(iucv_error_no_memory, 16);
 	ASCEBC(iucv_error_pathid, 16);
@@ -2084,15 +2061,11 @@ static int __init iucv_init(void)
 
 out_reboot:
 	unregister_reboot_notifier(&iucv_reboot_notifier);
-out_cpu:
-	cpu_notifier_register_begin();
-	__unregister_hotcpu_notifier(&iucv_cpu_notifier);
-out_free:
-	for_each_possible_cpu(cpu)
-		free_iucv_data(cpu);
-
-	cpu_notifier_register_done();
-
+out_remove_hp:
+	cpuhp_remove_state(iucv_online);
+out_prep:
+	cpuhp_remove_state(CPUHP_NET_IUCV_PREPARE);
+out_dev:
 	root_device_unregister(iucv_root);
 out_int:
 	unregister_external_irq(EXT_IRQ_IUCV, iucv_external_interrupt);
@@ -2110,7 +2083,6 @@ out:
 static void __exit iucv_exit(void)
 {
 	struct iucv_irq_list *p, *n;
-	int cpu;
 
 	spin_lock_irq(&iucv_queue_lock);
 	list_for_each_entry_safe(p, n, &iucv_task_queue, list)
@@ -2119,11 +2091,9 @@ static void __exit iucv_exit(void)
 		kfree(p);
 	spin_unlock_irq(&iucv_queue_lock);
 	unregister_reboot_notifier(&iucv_reboot_notifier);
-	cpu_notifier_register_begin();
-	__unregister_hotcpu_notifier(&iucv_cpu_notifier);
-	for_each_possible_cpu(cpu)
-		free_iucv_data(cpu);
-	cpu_notifier_register_done();
+
+	cpuhp_remove_state_nocalls(iucv_online);
+	cpuhp_remove_state(CPUHP_NET_IUCV_PREPARE);
 	root_device_unregister(iucv_root);
 	bus_unregister(&iucv_bus);
 	unregister_external_irq(EXT_IRQ_IUCV, iucv_external_interrupt);

net/xfrm/xfrm_policy.c

@@ -3113,6 +3113,7 @@ static struct pernet_operations __net_initdata xfrm_net_ops = {
 
 void __init xfrm_init(void)
 {
+	flow_cache_hp_init();
 	register_pernet_subsys(&xfrm_net_ops);
 	seqcount_init(&xfrm_policy_hash_generation);
 	xfrm_input_init();