Merge branch 'acpi-hotplug'

* acpi-hotplug:
  ACPI: Do not use CONFIG_ACPI_HOTPLUG_MEMORY_MODULE
  ACPI / cpufreq: Add ACPI processor device IDs to acpi-cpufreq
  Memory hotplug: Move alternative function definitions to header
  ACPI / processor: Fix potential NULL pointer dereference in acpi_processor_add()
  Memory hotplug / ACPI: Simplify memory removal
  ACPI / scan: Add second pass of companion offlining to hot-remove code
  Driver core / MM: Drop offline_memory_block()
  ACPI / processor: Pass processor object handle to acpi_bind_one()
  ACPI: Drop removal_type field from struct acpi_device
  Driver core / memory: Simplify __memory_block_change_state()
  ACPI / processor: Initialize per_cpu(processors, pr->id) properly
  CPU: Fix sysfs cpu/online of offlined CPUs
  Driver core: Introduce offline/online callbacks for memory blocks
  ACPI / memhotplug: Bind removable memory blocks to ACPI device nodes
  ACPI / processor: Use common hotplug infrastructure
  ACPI / hotplug: Use device offline/online for graceful hot-removal
  Driver core: Use generic offline/online for CPU offline/online
  Driver core: Add offline/online device operations

20 files changed, 1118 insertions, 928 deletions

diff --git a/Documentation/ABI/testing/sysfs-devices-online b/Documentation/ABI/testing/sysfs-devices-online
new file mode 100644
index 000000000000..f990026c0740
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-devices-online
@@ -0,0 +1,20 @@
+What:		/sys/devices/.../online
+Date:		April 2013
+Contact:	Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+Description:
+		The /sys/devices/.../online attribute is only present for
+		devices whose bus types provide .online() and .offline()
+		callbacks.  The number read from it (0 or 1) reflects the value
+		of the device's 'offline' field.  If that number is 1 and '0'
+		(or 'n', or 'N') is written to this file, the device bus type's
+		.offline() callback is executed for the device and (if
+		successful) its 'offline' field is updated accordingly.  In
+		turn, if that number is 0 and '1' (or 'y', or 'Y') is written to
+		this file, the device bus type's .online() callback is executed
+		for the device and (if successful) its 'offline' field is
+		updated as appropriate.
+
+		After a successful execution of the bus type's .offline()
+		callback the device cannot be used for any purpose until either
+		it is removed (i.e. device_del() is called for it), or its bus
+		type's .online() is exeucted successfully.
diff --git a/Documentation/ABI/testing/sysfs-firmware-acpi b/Documentation/ABI/testing/sysfs-firmware-acpi
index ce9bee98b43b..b4436cca97a8 100644
--- a/Documentation/ABI/testing/sysfs-firmware-acpi
+++ b/Documentation/ABI/testing/sysfs-firmware-acpi
@@ -44,6 +44,16 @@ Description:
 		or 0 (unset).  Attempts to write any other values to it will
 		cause -EINVAL to be returned.
 
+What:		/sys/firmware/acpi/hotplug/force_remove
+Date:		May 2013
+Contact:	Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+Description:
+		The number in this file (0 or 1) determines whether (1) or not
+		(0) the ACPI subsystem will allow devices to be hot-removed even
+		if they cannot be put offline gracefully (from the kernel's
+		viewpoint).  That number can be changed by writing a boolean
+		value to this file.
+
 What:		/sys/firmware/acpi/interrupts/
 Date:		February 2008
 Contact:	Len Brown <lenb@kernel.org>
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 536562c626a2..d07771bc3d8c 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -34,6 +34,7 @@ acpi-$(CONFIG_ACPI_SLEEP)	+= proc.o
 acpi-y				+= bus.o glue.o
 acpi-y				+= scan.o
 acpi-y				+= resource.o
+acpi-y				+= acpi_processor.o
 acpi-y				+= processor_core.o
 acpi-y				+= ec.o
 acpi-$(CONFIG_ACPI_DOCK)	+= dock.o
diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index 5e6301e94920..c711d1144044 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -28,6 +28,7 @@
  */
 
 #include <linux/acpi.h>
+#include <linux/memory.h>
 #include <linux/memory_hotplug.h>
 
 #include "internal.h"
@@ -166,13 +167,50 @@ static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
 	return 0;
 }
 
+static unsigned long acpi_meminfo_start_pfn(struct acpi_memory_info *info)
+{
+	return PFN_DOWN(info->start_addr);
+}
+
+static unsigned long acpi_meminfo_end_pfn(struct acpi_memory_info *info)
+{
+	return PFN_UP(info->start_addr + info->length-1);
+}
+
+static int acpi_bind_memblk(struct memory_block *mem, void *arg)
+{
+	return acpi_bind_one(&mem->dev, (acpi_handle)arg);
+}
+
+static int acpi_bind_memory_blocks(struct acpi_memory_info *info,
+				   acpi_handle handle)
+{
+	return walk_memory_range(acpi_meminfo_start_pfn(info),
+				 acpi_meminfo_end_pfn(info), (void *)handle,
+				 acpi_bind_memblk);
+}
+
+static int acpi_unbind_memblk(struct memory_block *mem, void *arg)
+{
+	acpi_unbind_one(&mem->dev);
+	return 0;
+}
+
+static void acpi_unbind_memory_blocks(struct acpi_memory_info *info,
+				      acpi_handle handle)
+{
+	walk_memory_range(acpi_meminfo_start_pfn(info),
+			  acpi_meminfo_end_pfn(info), NULL, acpi_unbind_memblk);
+}
+
 static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
 {
+	acpi_handle handle = mem_device->device->handle;
 	int result, num_enabled = 0;
 	struct acpi_memory_info *info;
 	int node;
 
-	node = acpi_get_node(mem_device->device->handle);
+	node = acpi_get_node(handle);
 	/*
 	 * Tell the VM there is more memory here...
 	 * Note: Assume that this function returns zero on success
@@ -203,6 +241,12 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
 		if (result && result != -EEXIST)
 			continue;
 
+		result = acpi_bind_memory_blocks(info, handle);
+		if (result) {
+			acpi_unbind_memory_blocks(info, handle);
+			return -ENODEV;
+		}
+
 		info->enabled = 1;
 
 		/*
@@ -227,12 +271,11 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
 	return 0;
 }
 
-static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
+static void acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
 {
-	int result = 0, nid;
+	acpi_handle handle = mem_device->device->handle;
 	struct acpi_memory_info *info, *n;
-
-	nid = acpi_get_node(mem_device->device->handle);
+	int nid = acpi_get_node(handle);
 
 	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
 		if (!info->enabled)
@@ -240,15 +283,12 @@ static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
 
 		if (nid < 0)
 			nid = memory_add_physaddr_to_nid(info->start_addr);
-		result = remove_memory(nid, info->start_addr, info->length);
-		if (result)
-			return result;
 
+		acpi_unbind_memory_blocks(info, handle);
+		remove_memory(nid, info->start_addr, info->length);
 		list_del(&info->list);
 		kfree(info);
 	}
-
-	return result;
 }
 
 static void acpi_memory_device_free(struct acpi_memory_device *mem_device)
@@ -300,7 +340,7 @@ static int acpi_memory_device_add(struct acpi_device *device,
 	if (result) {
 		dev_err(&device->dev, "acpi_memory_enable_device() error\n");
 		acpi_memory_device_free(mem_device);
-		return -ENODEV;
+		return result;
 	}
 
 	dev_dbg(&device->dev, "Memory device configured by ACPI\n");
diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
new file mode 100644
index 000000000000..e9b01e35ac37
--- /dev/null
+++ b/drivers/acpi/acpi_processor.c
@@ -0,0 +1,494 @@
+/*
+ * acpi_processor.c - ACPI processor enumeration support
+ *
+ * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
+ * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
+ * Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
+ * Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
+ * Copyright (C) 2013, Intel Corporation
+ *                     Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <linux/acpi.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+
+#include <acpi/processor.h>
+
+#include <asm/cpu.h>
+
+#include "internal.h"
+
+#define _COMPONENT	ACPI_PROCESSOR_COMPONENT
+
+ACPI_MODULE_NAME("processor");
+
+DEFINE_PER_CPU(struct acpi_processor *, processors);
+EXPORT_PER_CPU_SYMBOL(processors);
+
+/* --------------------------------------------------------------------------
+                                Errata Handling
+   -------------------------------------------------------------------------- */
+
+struct acpi_processor_errata errata __read_mostly;
+EXPORT_SYMBOL_GPL(errata);
+
+static int acpi_processor_errata_piix4(struct pci_dev *dev)
+{
+	u8 value1 = 0;
+	u8 value2 = 0;
+
+
+	if (!dev)
+		return -EINVAL;
+
+	/*
+	 * Note that 'dev' references the PIIX4 ACPI Controller.
+	 */
+
+	switch (dev->revision) {
+	case 0:
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4 A-step\n"));
+		break;
+	case 1:
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4 B-step\n"));
+		break;
+	case 2:
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4E\n"));
+		break;
+	case 3:
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4M\n"));
+		break;
+	default:
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found unknown PIIX4\n"));
+		break;
+	}
+
+	switch (dev->revision) {
+
+	case 0:		/* PIIX4 A-step */
+	case 1:		/* PIIX4 B-step */
+		/*
+		 * See specification changes #13 ("Manual Throttle Duty Cycle")
+		 * and #14 ("Enabling and Disabling Manual Throttle"), plus
+		 * erratum #5 ("STPCLK# Deassertion Time") from the January
+		 * 2002 PIIX4 specification update.  Applies to only older
+		 * PIIX4 models.
+		 */
+		errata.piix4.throttle = 1;
+
+	case 2:		/* PIIX4E */
+	case 3:		/* PIIX4M */
+		/*
+		 * See erratum #18 ("C3 Power State/BMIDE and Type-F DMA
+		 * Livelock") from the January 2002 PIIX4 specification update.
+		 * Applies to all PIIX4 models.
+		 */
+
+		/*
+		 * BM-IDE
+		 * ------
+		 * Find the PIIX4 IDE Controller and get the Bus Master IDE
+		 * Status register address.  We'll use this later to read
+		 * each IDE controller's DMA status to make sure we catch all
+		 * DMA activity.
+		 */
+		dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
+				     PCI_DEVICE_ID_INTEL_82371AB,
+				     PCI_ANY_ID, PCI_ANY_ID, NULL);
+		if (dev) {
+			errata.piix4.bmisx = pci_resource_start(dev, 4);
+			pci_dev_put(dev);
+		}
+
+		/*
+		 * Type-F DMA
+		 * ----------
+		 * Find the PIIX4 ISA Controller and read the Motherboard
+		 * DMA controller's status to see if Type-F (Fast) DMA mode
+		 * is enabled (bit 7) on either channel.  Note that we'll
+		 * disable C3 support if this is enabled, as some legacy
+		 * devices won't operate well if fast DMA is disabled.
+		 */
+		dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
+				     PCI_DEVICE_ID_INTEL_82371AB_0,
+				     PCI_ANY_ID, PCI_ANY_ID, NULL);
+		if (dev) {
+			pci_read_config_byte(dev, 0x76, &value1);
+			pci_read_config_byte(dev, 0x77, &value2);
+			if ((value1 & 0x80) || (value2 & 0x80))
+				errata.piix4.fdma = 1;
+			pci_dev_put(dev);
+		}
+
+		break;
+	}
+
+	if (errata.piix4.bmisx)
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+				  "Bus master activity detection (BM-IDE) erratum enabled\n"));
+	if (errata.piix4.fdma)
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+				  "Type-F DMA livelock erratum (C3 disabled)\n"));
+
+	return 0;
+}
+
+static int acpi_processor_errata(struct acpi_processor *pr)
+{
+	int result = 0;
+	struct pci_dev *dev = NULL;
+
+
+	if (!pr)
+		return -EINVAL;
+
+	/*
+	 * PIIX4
+	 */
+	dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
+			     PCI_DEVICE_ID_INTEL_82371AB_3, PCI_ANY_ID,
+			     PCI_ANY_ID, NULL);
+	if (dev) {
+		result = acpi_processor_errata_piix4(dev);
+		pci_dev_put(dev);
+	}
+
+	return result;
+}
+
+/* --------------------------------------------------------------------------
+                                Initialization
+   -------------------------------------------------------------------------- */
+
+#ifdef CONFIG_ACPI_HOTPLUG_CPU
+static int acpi_processor_hotadd_init(struct acpi_processor *pr)
+{
+	unsigned long long sta;
+	acpi_status status;
+	int ret;
+
+	status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta);
+	if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_PRESENT))
+		return -ENODEV;
+
+	ret = acpi_map_lsapic(pr->handle, &pr->id);
+	if (ret)
+		return ret;
+
+	ret = arch_register_cpu(pr->id);
+	if (ret) {
+		acpi_unmap_lsapic(pr->id);
+		return ret;
+	}
+
+	/*
+	 * CPU got hot-added, but cpu_data is not initialized yet.  Set a flag
+	 * to delay cpu_idle/throttling initialization and do it when the CPU
+	 * gets online for the first time.
+	 */
+	pr_info("CPU%d has been hot-added\n", pr->id);
+	pr->flags.need_hotplug_init = 1;
+	return 0;
+}
+#else
+static inline int acpi_processor_hotadd_init(struct acpi_processor *pr)
+{
+	return -ENODEV;
+}
+#endif /* CONFIG_ACPI_HOTPLUG_CPU */
+
+static int acpi_processor_get_info(struct acpi_device *device)
+{
+	union acpi_object object = { 0 };
+	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
+	struct acpi_processor *pr = acpi_driver_data(device);
+	int cpu_index, device_declaration = 0;
+	acpi_status status = AE_OK;
+	static int cpu0_initialized;
+
+	if (num_online_cpus() > 1)
+		errata.smp = TRUE;
+
+	acpi_processor_errata(pr);
+
+	/*
+	 * Check to see if we have bus mastering arbitration control.  This
+	 * is required for proper C3 usage (to maintain cache coherency).
+	 */
+	if (acpi_gbl_FADT.pm2_control_block && acpi_gbl_FADT.pm2_control_length) {
+		pr->flags.bm_control = 1;
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+				  "Bus mastering arbitration control present\n"));
+	} else
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+				  "No bus mastering arbitration control\n"));
+
+	if (!strcmp(acpi_device_hid(device), ACPI_PROCESSOR_OBJECT_HID)) {
+		/* Declared with "Processor" statement; match ProcessorID */
+		status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer);
+		if (ACPI_FAILURE(status)) {
+			dev_err(&device->dev,
+				"Failed to evaluate processor object (0x%x)\n",
+				status);
+			return -ENODEV;
+		}
+
+		/*
+		 * TBD: Synch processor ID (via LAPIC/LSAPIC structures) on SMP.
+		 *      >>> 'acpi_get_processor_id(acpi_id, &id)' in
+		 *      arch/xxx/acpi.c
+		 */
+		pr->acpi_id = object.processor.proc_id;
+	} else {
+		/*
+		 * Declared with "Device" statement; match _UID.
+		 * Note that we don't handle string _UIDs yet.
+		 */
+		unsigned long long value;
+		status = acpi_evaluate_integer(pr->handle, METHOD_NAME__UID,
+						NULL, &value);
+		if (ACPI_FAILURE(status)) {
+			dev_err(&device->dev,
+				"Failed to evaluate processor _UID (0x%x)\n",
+				status);
+			return -ENODEV;
+		}
+		device_declaration = 1;
+		pr->acpi_id = value;
+	}
+	cpu_index = acpi_get_cpuid(pr->handle, device_declaration, pr->acpi_id);
+
+	/* Handle UP system running SMP kernel, with no LAPIC in MADT */
+	if (!cpu0_initialized && (cpu_index == -1) &&
+	    (num_online_cpus() == 1)) {
+		cpu_index = 0;
+	}
+
+	cpu0_initialized = 1;
+
+	pr->id = cpu_index;
+
+	/*
+	 *  Extra Processor objects may be enumerated on MP systems with
+	 *  less than the max # of CPUs. They should be ignored _iff
+	 *  they are physically not present.
+	 */
+	if (pr->id == -1) {
+		int ret = acpi_processor_hotadd_init(pr);
+		if (ret)
+			return ret;
+	}
+	/*
+	 * On some boxes several processors use the same processor bus id.
+	 * But they are located in different scope. For example:
+	 * \_SB.SCK0.CPU0
+	 * \_SB.SCK1.CPU0
+	 * Rename the processor device bus id. And the new bus id will be
+	 * generated as the following format:
+	 * CPU+CPU ID.
+	 */
+	sprintf(acpi_device_bid(device), "CPU%X", pr->id);
+	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Processor [%d:%d]\n", pr->id,
+			  pr->acpi_id));
+
+	if (!object.processor.pblk_address)
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No PBLK (NULL address)\n"));
+	else if (object.processor.pblk_length != 6)
+		dev_err(&device->dev, "Invalid PBLK length [%d]\n",
+			    object.processor.pblk_length);
+	else {
+		pr->throttling.address = object.processor.pblk_address;
+		pr->throttling.duty_offset = acpi_gbl_FADT.duty_offset;
+		pr->throttling.duty_width = acpi_gbl_FADT.duty_width;
+
+		pr->pblk = object.processor.pblk_address;
+
+		/*
+		 * We don't care about error returns - we just try to mark
+		 * these reserved so that nobody else is confused into thinking
+		 * that this region might be unused..
+		 *
+		 * (In particular, allocating the IO range for Cardbus)
+		 */
+		request_region(pr->throttling.address, 6, "ACPI CPU throttle");
+	}
+
+	/*
+	 * If ACPI describes a slot number for this CPU, we can use it to
+	 * ensure we get the right value in the "physical id" field
+	 * of /proc/cpuinfo
+	 */
+	status = acpi_evaluate_object(pr->handle, "_SUN", NULL, &buffer);
+	if (ACPI_SUCCESS(status))
+		arch_fix_phys_package_id(pr->id, object.integer.value);
+
+	return 0;
+}
+
+/*
+ * Do not put anything in here which needs the core to be online.
+ * For example MSR access or setting up things which check for cpuinfo_x86
+ * (cpu_data(cpu)) values, like CPU feature flags, family, model, etc.
+ * Such things have to be put in and set up by the processor driver's .probe().
+ */
+static DEFINE_PER_CPU(void *, processor_device_array);
+
+static int __cpuinit acpi_processor_add(struct acpi_device *device,
+					const struct acpi_device_id *id)
+{
+	struct acpi_processor *pr;
+	struct device *dev;
+	int result = 0;
+
+	pr = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
+	if (!pr)
+		return -ENOMEM;
+
+	if (!zalloc_cpumask_var(&pr->throttling.shared_cpu_map, GFP_KERNEL)) {
+		result = -ENOMEM;
+		goto err_free_pr;
+	}
+
+	pr->handle = device->handle;
+	strcpy(acpi_device_name(device), ACPI_PROCESSOR_DEVICE_NAME);
+	strcpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS);
+	device->driver_data = pr;
+
+	result = acpi_processor_get_info(device);
+	if (result) /* Processor is not physically present or unavailable */
+		return 0;
+
+#ifdef CONFIG_SMP
+	if (pr->id >= setup_max_cpus && pr->id != 0)
+		return 0;
+#endif
+
+	BUG_ON(pr->id >= nr_cpu_ids);
+
+	/*
+	 * Buggy BIOS check.
+	 * ACPI id of processors can be reported wrongly by the BIOS.
+	 * Don't trust it blindly
+	 */
+	if (per_cpu(processor_device_array, pr->id) != NULL &&
+	    per_cpu(processor_device_array, pr->id) != device) {
+		dev_warn(&device->dev,
+			"BIOS reported wrong ACPI id %d for the processor\n",
+			pr->id);
+		/* Give up, but do not abort the namespace scan. */
+		goto err;
+	}
+	/*
+	 * processor_device_array is not cleared on errors to allow buggy BIOS
+	 * checks.
+	 */
+	per_cpu(processor_device_array, pr->id) = device;
+	per_cpu(processors, pr->id) = pr;
+
+	dev = get_cpu_device(pr->id);
+	if (!dev) {
+		result = -ENODEV;
+		goto err;
+	}
+
+	result = acpi_bind_one(dev, pr->handle);
+	if (result)
+		goto err;
+
+	pr->dev = dev;
+	dev->offline = pr->flags.need_hotplug_init;
+
+	/* Trigger the processor driver's .probe() if present. */
+	if (device_attach(dev) >= 0)
+		return 1;
+
+	dev_err(dev, "Processor driver could not be attached\n");
+	acpi_unbind_one(dev);
+
+ err:
+	free_cpumask_var(pr->throttling.shared_cpu_map);
+	device->driver_data = NULL;
+	per_cpu(processors, pr->id) = NULL;
+ err_free_pr:
+	kfree(pr);
+	return result;
+}
+
+#ifdef CONFIG_ACPI_HOTPLUG_CPU
+/* --------------------------------------------------------------------------
+                                    Removal
+   -------------------------------------------------------------------------- */
+
+static void acpi_processor_remove(struct acpi_device *device)
+{
+	struct acpi_processor *pr;
+
+	if (!device || !acpi_driver_data(device))
+		return;
+
+	pr = acpi_driver_data(device);
+	if (pr->id >= nr_cpu_ids)
+		goto out;
+
+	/*
+	 * The only reason why we ever get here is CPU hot-removal.  The CPU is
+	 * already offline and the ACPI device removal locking prevents it from
+	 * being put back online at this point.
+	 *
+	 * Unbind the driver from the processor device and detach it from the
+	 * ACPI companion object.
+	 */
+	device_release_driver(pr->dev);
+	acpi_unbind_one(pr->dev);
+
+	/* Clean up. */
+	per_cpu(processor_device_array, pr->id) = NULL;
+	per_cpu(processors, pr->id) = NULL;
+	try_offline_node(cpu_to_node(pr->id));
+
+	/* Remove the CPU. */
+	get_online_cpus();
+	arch_unregister_cpu(pr->id);
+	acpi_unmap_lsapic(pr->id);
+	put_online_cpus();
+
+ out:
+	free_cpumask_var(pr->throttling.shared_cpu_map);
+	kfree(pr);
+}
+#endif /* CONFIG_ACPI_HOTPLUG_CPU */
+
+/*
+ * The following ACPI IDs are known to be suitable for representing as
+ * processor devices.
+ */
+static const struct acpi_device_id processor_device_ids[] = {
+
+	{ ACPI_PROCESSOR_OBJECT_HID, },
+	{ ACPI_PROCESSOR_DEVICE_HID, },
+
+	{ }
+};
+
+static struct acpi_scan_handler __refdata processor_handler = {
+	.ids = processor_device_ids,
+	.attach = acpi_processor_add,
+#ifdef CONFIG_ACPI_HOTPLUG_CPU
+	.detach = acpi_processor_remove,
+#endif
+	.hotplug = {
+		.enabled = true,
+	},
+};
+
+void __init acpi_processor_init(void)
+{
+	acpi_scan_add_handler_with_hotplug(&processor_handler, "processor");
+}
diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c
index 40a84cc6740c..9783f400d857 100644
--- a/drivers/acpi/glue.c
+++ b/drivers/acpi/glue.c
@@ -105,7 +105,7 @@ acpi_handle acpi_get_child(acpi_handle parent, u64 address)
 }
 EXPORT_SYMBOL(acpi_get_child);
 
-static int acpi_bind_one(struct device *dev, acpi_handle handle)
+int acpi_bind_one(struct device *dev, acpi_handle handle)
 {
 	struct acpi_device *acpi_dev;
 	acpi_status status;
@@ -188,8 +188,9 @@ static int acpi_bind_one(struct device *dev, acpi_handle handle)
 	kfree(physical_node);
 	goto err;
 }
+EXPORT_SYMBOL_GPL(acpi_bind_one);
 
-static int acpi_unbind_one(struct device *dev)
+int acpi_unbind_one(struct device *dev)
 {
 	struct acpi_device_physical_node *entry;
 	struct acpi_device *acpi_dev;
@@ -238,6 +239,7 @@ err:
 	dev_err(dev, "Oops, 'acpi_handle' corrupt\n");
 	return -EINVAL;
 }
+EXPORT_SYMBOL_GPL(acpi_unbind_one);
 
 static int acpi_platform_notify(struct device *dev)
 {
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index c610a76d92c4..520073ba36b4 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -33,6 +33,7 @@ static inline void acpi_pci_slot_init(void) { }
 void acpi_pci_root_init(void);
 void acpi_pci_link_init(void);
 void acpi_pci_root_hp_init(void);
+void acpi_processor_init(void);
 void acpi_platform_init(void);
 int acpi_sysfs_init(void);
 #ifdef CONFIG_ACPI_CONTAINER
@@ -51,6 +52,8 @@ void acpi_memory_hotplug_init(void);
 static inline void acpi_memory_hotplug_init(void) {}
 #endif
 
+extern bool acpi_force_hot_remove;
+
 void acpi_sysfs_add_hotplug_profile(struct acpi_hotplug_profile *hotplug,
 				    const char *name);
 int acpi_scan_add_handler_with_hotplug(struct acpi_scan_handler *handler,
@@ -81,6 +84,8 @@ void acpi_init_device_object(struct acpi_device *device, acpi_handle handle,
 			     int type, unsigned long long sta);
 void acpi_device_add_finalize(struct acpi_device *device);
 void acpi_free_pnp_ids(struct acpi_device_pnp *pnp);
+int acpi_bind_one(struct device *dev, acpi_handle handle);
+int acpi_unbind_one(struct device *dev);
 
 /* --------------------------------------------------------------------------
                                   Power Resource
diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
index c266cdc11784..d93963f1e8f4 100644
--- a/drivers/acpi/processor_driver.c
+++ b/drivers/acpi/processor_driver.c
@@ -1,11 +1,13 @@
 /*
- * acpi_processor.c - ACPI Processor Driver ($Revision: 71 $)
+ * processor_driver.c - ACPI Processor Driver
  *
  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
  *  Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
  *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
  *  			- Added processor hotplug support
+ *  Copyright (C) 2013, Intel Corporation
+ *                      Rafael J. Wysocki <rafael.j.wysocki@intel.com>
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  *
@@ -24,52 +26,29 @@
  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
- *  TBD:
- *	1. Make # power states dynamic.
- *	2. Support duty_cycle values that span bit 4.
- *	3. Optimize by having scheduler determine business instead of
- *	   having us try to calculate it here.
- *	4. Need C1 timing -- must modify kernel (IRQ handler) to get this.
  */
 
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
-#include <linux/types.h>
-#include <linux/pci.h>
-#include <linux/pm.h>
 #include <linux/cpufreq.h>
 #include <linux/cpu.h>
-#include <linux/dmi.h>
-#include <linux/moduleparam.h>
 #include <linux/cpuidle.h>
 #include <linux/slab.h>
 #include <linux/acpi.h>
-#include <linux/memory_hotplug.h>
-
-#include <asm/io.h>
-#include <asm/cpu.h>
-#include <asm/delay.h>
-#include <asm/uaccess.h>
-#include <asm/processor.h>
-#include <asm/smp.h>
-#include <asm/acpi.h>
-
-#include <acpi/acpi_bus.h>
-#include <acpi/acpi_drivers.h>
+
 #include <acpi/processor.h>
 
+#include "internal.h"
+
 #define PREFIX "ACPI: "
 
-#define ACPI_PROCESSOR_CLASS		"processor"
-#define ACPI_PROCESSOR_DEVICE_NAME	"Processor"
 #define ACPI_PROCESSOR_FILE_INFO	"info"
 #define ACPI_PROCESSOR_FILE_THROTTLING	"throttling"
 #define ACPI_PROCESSOR_FILE_LIMIT	"limit"
 #define ACPI_PROCESSOR_NOTIFY_PERFORMANCE 0x80
 #define ACPI_PROCESSOR_NOTIFY_POWER	0x81
 #define ACPI_PROCESSOR_NOTIFY_THROTTLING	0x82
-#define ACPI_PROCESSOR_DEVICE_HID	"ACPI0007"
 
 #define ACPI_PROCESSOR_LIMIT_USER	0
 #define ACPI_PROCESSOR_LIMIT_THERMAL	1
@@ -81,12 +60,8 @@ MODULE_AUTHOR("Paul Diefenbaugh");
 MODULE_DESCRIPTION("ACPI Processor Driver");
 MODULE_LICENSE("GPL");
 
-static int acpi_processor_add(struct acpi_device *device);
-static int acpi_processor_remove(struct acpi_device *device);
-static void acpi_processor_notify(struct acpi_device *device, u32 event);
-static acpi_status acpi_processor_hotadd_init(struct acpi_processor *pr);
-static int acpi_processor_handle_eject(struct acpi_processor *pr);
-static int acpi_processor_start(struct acpi_processor *pr);
+static int acpi_processor_start(struct device *dev);
+static int acpi_processor_stop(struct device *dev);
 
 static const struct acpi_device_id processor_device_ids[] = {
 	{ACPI_PROCESSOR_OBJECT_HID, 0},
@@ -95,295 +70,24 @@ static const struct acpi_device_id processor_device_ids[] = {
 };
 MODULE_DEVICE_TABLE(acpi, processor_device_ids);
 
-static struct acpi_driver acpi_processor_driver = {
+static struct device_driver acpi_processor_driver = {
 	.name = "processor",
-	.class = ACPI_PROCESSOR_CLASS,
-	.ids = processor_device_ids,
-	.ops = {
-		.add = acpi_processor_add,
-		.remove = acpi_processor_remove,
-		.notify = acpi_processor_notify,
-		},
+	.bus = &cpu_subsys,
+	.acpi_match_table = processor_device_ids,
+	.probe = acpi_processor_start,
+	.remove = acpi_processor_stop,
 };
 
-#define INSTALL_NOTIFY_HANDLER		1
-#define UNINSTALL_NOTIFY_HANDLER	2
-
-DEFINE_PER_CPU(struct acpi_processor *, processors);
-EXPORT_PER_CPU_SYMBOL(processors);
-
-struct acpi_processor_errata errata __read_mostly;
-
-/* --------------------------------------------------------------------------
-                                Errata Handling
-   -------------------------------------------------------------------------- */
-
-static int acpi_processor_errata_piix4(struct pci_dev *dev)
+static void acpi_processor_notify(acpi_handle handle, u32 event, void *data)
 {
-	u8 value1 = 0;
-	u8 value2 = 0;
-
-
-	if (!dev)
-		return -EINVAL;
-
-	/*
-	 * Note that 'dev' references the PIIX4 ACPI Controller.
-	 */
-
-	switch (dev->revision) {
-	case 0:
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4 A-step\n"));
-		break;
-	case 1:
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4 B-step\n"));
-		break;
-	case 2:
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4E\n"));
-		break;
-	case 3:
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4M\n"));
-		break;
-	default:
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found unknown PIIX4\n"));
-		break;
-	}
-
-	switch (dev->revision) {
-
-	case 0:		/* PIIX4 A-step */
-	case 1:		/* PIIX4 B-step */
-		/*
-		 * See specification changes #13 ("Manual Throttle Duty Cycle")
-		 * and #14 ("Enabling and Disabling Manual Throttle"), plus
-		 * erratum #5 ("STPCLK# Deassertion Time") from the January
-		 * 2002 PIIX4 specification update.  Applies to only older
-		 * PIIX4 models.
-		 */
-		errata.piix4.throttle = 1;
-
-	case 2:		/* PIIX4E */
-	case 3:		/* PIIX4M */
-		/*
-		 * See erratum #18 ("C3 Power State/BMIDE and Type-F DMA
-		 * Livelock") from the January 2002 PIIX4 specification update.
-		 * Applies to all PIIX4 models.
-		 */
-
-		/*
-		 * BM-IDE
-		 * ------
-		 * Find the PIIX4 IDE Controller and get the Bus Master IDE
-		 * Status register address.  We'll use this later to read
-		 * each IDE controller's DMA status to make sure we catch all
-		 * DMA activity.
-		 */
-		dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
-				     PCI_DEVICE_ID_INTEL_82371AB,
-				     PCI_ANY_ID, PCI_ANY_ID, NULL);
-		if (dev) {
-			errata.piix4.bmisx = pci_resource_start(dev, 4);
-			pci_dev_put(dev);
-		}
-
-		/*
-		 * Type-F DMA
-		 * ----------
-		 * Find the PIIX4 ISA Controller and read the Motherboard
-		 * DMA controller's status to see if Type-F (Fast) DMA mode
-		 * is enabled (bit 7) on either channel.  Note that we'll
-		 * disable C3 support if this is enabled, as some legacy
-		 * devices won't operate well if fast DMA is disabled.
-		 */
-		dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
-				     PCI_DEVICE_ID_INTEL_82371AB_0,
-				     PCI_ANY_ID, PCI_ANY_ID, NULL);
-		if (dev) {
-			pci_read_config_byte(dev, 0x76, &value1);
-			pci_read_config_byte(dev, 0x77, &value2);
-			if ((value1 & 0x80) || (value2 & 0x80))
-				errata.piix4.fdma = 1;
-			pci_dev_put(dev);
-		}
-
-		break;
-	}
-
-	if (errata.piix4.bmisx)
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
-				  "Bus master activity detection (BM-IDE) erratum enabled\n"));
-	if (errata.piix4.fdma)
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
-				  "Type-F DMA livelock erratum (C3 disabled)\n"));
-
-	return 0;
-}
-
-static int acpi_processor_errata(struct acpi_processor *pr)
-{
-	int result = 0;
-	struct pci_dev *dev = NULL;
-
-
-	if (!pr)
-		return -EINVAL;
-
-	/*
-	 * PIIX4
-	 */
-	dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
-			     PCI_DEVICE_ID_INTEL_82371AB_3, PCI_ANY_ID,
-			     PCI_ANY_ID, NULL);
-	if (dev) {
-		result = acpi_processor_errata_piix4(dev);
-		pci_dev_put(dev);
-	}
-
-	return result;
-}
-
-/* --------------------------------------------------------------------------
-                                 Driver Interface
-   -------------------------------------------------------------------------- */
-
-static int acpi_processor_get_info(struct acpi_device *device)
-{
-	acpi_status status = 0;
-	union acpi_object object = { 0 };
-	struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
+	struct acpi_device *device = data;
 	struct acpi_processor *pr;
-	int cpu_index, device_declaration = 0;
-	static int cpu0_initialized;
-
-	pr = acpi_driver_data(device);
-	if (!pr)
-		return -EINVAL;
-
-	if (num_online_cpus() > 1)
-		errata.smp = TRUE;
-
-	acpi_processor_errata(pr);
-
-	/*
-	 * Check to see if we have bus mastering arbitration control.  This
-	 * is required for proper C3 usage (to maintain cache coherency).
-	 */
-	if (acpi_gbl_FADT.pm2_control_block && acpi_gbl_FADT.pm2_control_length) {
-		pr->flags.bm_control = 1;
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
-				  "Bus mastering arbitration control present\n"));
-	} else
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
-				  "No bus mastering arbitration control\n"));
-
-	if (!strcmp(acpi_device_hid(device), ACPI_PROCESSOR_OBJECT_HID)) {
-		/* Declared with "Processor" statement; match ProcessorID */
-		status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer);
-		if (ACPI_FAILURE(status)) {
-			dev_err(&device->dev,
-				"Failed to evaluate processor object (0x%x)\n",
-				status);
-			return -ENODEV;
-		}
-
-		/*
-		 * TBD: Synch processor ID (via LAPIC/LSAPIC structures) on SMP.
-		 *      >>> 'acpi_get_processor_id(acpi_id, &id)' in
-		 *      arch/xxx/acpi.c
-		 */
-		pr->acpi_id = object.processor.proc_id;
-	} else {
-		/*
-		 * Declared with "Device" statement; match _UID.
-		 * Note that we don't handle string _UIDs yet.
-		 */
-		unsigned long long value;
-		status = acpi_evaluate_integer(pr->handle, METHOD_NAME__UID,
-						NULL, &value);
-		if (ACPI_FAILURE(status)) {
-			dev_err(&device->dev,
-				"Failed to evaluate processor _UID (0x%x)\n",
-				status);
-			return -ENODEV;
-		}
-		device_declaration = 1;
-		pr->acpi_id = value;
-	}
-	cpu_index = acpi_get_cpuid(pr->handle, device_declaration, pr->acpi_id);
-
-	/* Handle UP system running SMP kernel, with no LAPIC in MADT */
-	if (!cpu0_initialized && (cpu_index == -1) &&
-	    (num_online_cpus() == 1)) {
-		cpu_index = 0;
-	}
-
-	cpu0_initialized = 1;
-
-	pr->id = cpu_index;
-
-	/*
-	 *  Extra Processor objects may be enumerated on MP systems with
-	 *  less than the max # of CPUs. They should be ignored _iff
-	 *  they are physically not present.
-	 */
-	if (pr->id == -1) {
-		if (ACPI_FAILURE(acpi_processor_hotadd_init(pr)))
-			return -ENODEV;
-	}
-	/*
-	 * On some boxes several processors use the same processor bus id.
-	 * But they are located in different scope. For example:
-	 * \_SB.SCK0.CPU0
-	 * \_SB.SCK1.CPU0
-	 * Rename the processor device bus id. And the new bus id will be
-	 * generated as the following format:
-	 * CPU+CPU ID.
-	 */
-	sprintf(acpi_device_bid(device), "CPU%X", pr->id);
-	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Processor [%d:%d]\n", pr->id,
-			  pr->acpi_id));
-
-	if (!object.processor.pblk_address)
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No PBLK (NULL address)\n"));
-	else if (object.processor.pblk_length != 6)
-		dev_err(&device->dev, "Invalid PBLK length [%d]\n",
-			    object.processor.pblk_length);
-	else {
-		pr->throttling.address = object.processor.pblk_address;
-		pr->throttling.duty_offset = acpi_gbl_FADT.duty_offset;
-		pr->throttling.duty_width = acpi_gbl_FADT.duty_width;
-
-		pr->pblk = object.processor.pblk_address;
-
-		/*
-		 * We don't care about error returns - we just try to mark
-		 * these reserved so that nobody else is confused into thinking
-		 * that this region might be unused..
-		 *
-		 * (In particular, allocating the IO range for Cardbus)
-		 */
-		request_region(pr->throttling.address, 6, "ACPI CPU throttle");
-	}
-
-	/*
-	 * If ACPI describes a slot number for this CPU, we can use it
-	 * ensure we get the right value in the "physical id" field
-	 * of /proc/cpuinfo
-	 */
-	status = acpi_evaluate_object(pr->handle, "_SUN", NULL, &buffer);
-	if (ACPI_SUCCESS(status))
-		arch_fix_phys_package_id(pr->id, object.integer.value);
-
-	return 0;
-}
-
-static DEFINE_PER_CPU(void *, processor_device_array);
-
-static void acpi_processor_notify(struct acpi_device *device, u32 event)
-{
-	struct acpi_processor *pr = acpi_driver_data(device);
 	int saved;
 
+	if (device->handle != handle)
+		return;
+
+	pr = acpi_driver_data(device);
 	if (!pr)
 		return;
 
@@ -420,55 +124,62 @@ static void acpi_processor_notify(struct acpi_device *device, u32 event)
 	return;
 }
 
-static int acpi_cpu_soft_notify(struct notifier_block *nfb,
-		unsigned long action, void *hcpu)
+static __cpuinit int __acpi_processor_start(struct acpi_device *device);
+
+static int __cpuinit acpi_cpu_soft_notify(struct notifier_block *nfb,
+					  unsigned long action, void *hcpu)
 {
 	unsigned int cpu = (unsigned long)hcpu;
 	struct acpi_processor *pr = per_cpu(processors, cpu);
+	struct acpi_device *device;
+
+	if (!pr || acpi_bus_get_device(pr->handle, &device))
+		return NOTIFY_DONE;
 
-	if (action == CPU_ONLINE && pr) {
-		/* CPU got physically hotplugged and onlined the first time:
-		 * Initialize missing things
+	if (action == CPU_ONLINE) {
+		/*
+		 * CPU got physically hotplugged and onlined for the first time:
+		 * Initialize missing things.
 		 */
 		if (pr->flags.need_hotplug_init) {
+			int ret;
+
 			pr_info("Will online and init hotplugged CPU: %d\n",
 				pr->id);
-			WARN(acpi_processor_start(pr), "Failed to start CPU:"
-				" %d\n", pr->id);
 			pr->flags.need_hotplug_init = 0;
-		/* Normal CPU soft online event */
+			ret = __acpi_processor_start(device);
+			WARN(ret, "Failed to start CPU: %d\n", pr->id);
 		} else {
+			/* Normal CPU soft online event. */
 			acpi_processor_ppc_has_changed(pr, 0);
 			acpi_processor_hotplug(pr);
 			acpi_processor_reevaluate_tstate(pr, action);
 			acpi_processor_tstate_has_changed(pr);
 		}
-	}
-	if (action == CPU_DEAD && pr) {
-		/* invalidate the flag.throttling after one CPU is offline */
+	} else if (action == CPU_DEAD) {
+		/* Invalidate flag.throttling after the CPU is offline. */
 		acpi_processor_reevaluate_tstate(pr, action);
 	}
 	return NOTIFY_OK;
 }
 
-static struct notifier_block acpi_cpu_notifier =
+static struct notifier_block __refdata acpi_cpu_notifier =
 {
 	    .notifier_call = acpi_cpu_soft_notify,
 };
 
-/*
- * acpi_processor_start() is called by the cpu_hotplug_notifier func:
- * acpi_cpu_soft_notify(). Getting it __cpuinit{data} is difficult, the
- * root cause seem to be that acpi_processor_uninstall_hotplug_notify()
- * is in the module_exit (__exit) func. Allowing acpi_processor_start()
- * to not be in __cpuinit section, but being called from __cpuinit funcs
- * via __ref looks like the right thing to do here.
- */
-static __ref int acpi_processor_start(struct acpi_processor *pr)
+static __cpuinit int __acpi_processor_start(struct acpi_device *device)
 {
-	struct acpi_device *device = per_cpu(processor_device_array, pr->id);
+	struct acpi_processor *pr = acpi_driver_data(device);
+	acpi_status status;
 	int result = 0;
 
+	if (!pr)
+		return -ENODEV;
+
+	if (pr->flags.need_hotplug_init)
+		return 0;
+
 #ifdef CONFIG_CPU_FREQ
 	acpi_processor_ppc_has_changed(pr, 0);
 	acpi_processor_load_module(pr);
@@ -506,462 +217,95 @@ static __ref int acpi_processor_start(struct acpi_processor *pr)
 		goto err_remove_sysfs_thermal;
 	}
 
-	return 0;
+	status = acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
+					     acpi_processor_notify, device);
+	if (ACPI_SUCCESS(status))
+		return 0;
 
-err_remove_sysfs_thermal:
+	sysfs_remove_link(&pr->cdev->device.kobj, "device");
+ err_remove_sysfs_thermal:
 	sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
-err_thermal_unregister:
+ err_thermal_unregister:
 	thermal_cooling_device_unregister(pr->cdev);
-err_power_exit:
+ err_power_exit:
 	acpi_processor_power_exit(pr);
-
 	return result;
 }
 
-/*
- * Do not put anything in here which needs the core to be online.
- * For example MSR access or setting up things which check for cpuinfo_x86
- * (cpu_data(cpu)) values, like CPU feature flags, family, model, etc.
- * Such things have to be put in and set up above in acpi_processor_start()
- */
-static int __cpuinit acpi_processor_add(struct acpi_device *device)
+static int __cpuinit acpi_processor_start(struct device *dev)
 {
-	struct acpi_processor *pr = NULL;
-	int result = 0;
-	struct device *dev;
-
-	pr = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
-	if (!pr)
-		return -ENOMEM;
-
-	if (!zalloc_cpumask_var(&pr->throttling.shared_cpu_map, GFP_KERNEL)) {
-		result = -ENOMEM;
-		goto err_free_pr;
-	}
-
-	pr->handle = device->handle;
-	strcpy(acpi_device_name(device), ACPI_PROCESSOR_DEVICE_NAME);
-	strcpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS);
-	device->driver_data = pr;
-
-	result = acpi_processor_get_info(device);
-	if (result) {
-		/* Processor is physically not present */
-		return 0;
-	}
-
-#ifdef CONFIG_SMP
-	if (pr->id >= setup_max_cpus && pr->id != 0)
-		return 0;
-#endif
-
-	BUG_ON(pr->id >= nr_cpu_ids);
-
-	/*
-	 * Buggy BIOS check
-	 * ACPI id of processors can be reported wrongly by the BIOS.
-	 * Don't trust it blindly
-	 */
-	if (per_cpu(processor_device_array, pr->id) != NULL &&
-	    per_cpu(processor_device_array, pr->id) != device) {
-		dev_warn(&device->dev,
-			"BIOS reported wrong ACPI id %d for the processor\n",
-			pr->id);
-		result = -ENODEV;
-		goto err_free_cpumask;
-	}
-	per_cpu(processor_device_array, pr->id) = device;
-
-	per_cpu(processors, pr->id) = pr;
-
-	dev = get_cpu_device(pr->id);
-	if (sysfs_create_link(&device->dev.kobj, &dev->kobj, "sysdev")) {
-		result = -EFAULT;
-		goto err_clear_processor;
-	}
+	struct acpi_device *device;
 
-	/*
-	 * Do not start hotplugged CPUs now, but when they
-	 * are onlined the first time
-	 */
-	if (pr->flags.need_hotplug_init)
-		return 0;
-
-	result = acpi_processor_start(pr);
-	if (result)
-		goto err_remove_sysfs;
-
-	return 0;
+	if (acpi_bus_get_device(ACPI_HANDLE(dev), &device))
+		return -ENODEV;
 
-err_remove_sysfs:
-	sysfs_remove_link(&device->dev.kobj, "sysdev");
-err_clear_processor:
-	/*
-	 * processor_device_array is not cleared to allow checks for buggy BIOS
-	 */ 
-	per_cpu(processors, pr->id) = NULL;
-err_free_cpumask:
-	free_cpumask_var(pr->throttling.shared_cpu_map);
-err_free_pr:
-	kfree(pr);
-	return result;
+	return __acpi_processor_start(device);
 }
 
-static int acpi_processor_remove(struct acpi_device *device)
+static int acpi_processor_stop(struct device *dev)
 {
-	struct acpi_processor *pr = NULL;
+	struct acpi_device *device;
+	struct acpi_processor *pr;
 
+	if (acpi_bus_get_device(ACPI_HANDLE(dev), &device))
+		return 0;
 
-	if (!device || !acpi_driver_data(device))
-		return -EINVAL;
+	acpi_remove_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
+				   acpi_processor_notify);
 
 	pr = acpi_driver_data(device);
-
-	if (pr->id >= nr_cpu_ids)
-		goto free;
-
-	if (device->removal_type == ACPI_BUS_REMOVAL_EJECT) {
-		if (acpi_processor_handle_eject(pr))
-			return -EINVAL;
-	}
+	if (!pr)
+		return 0;
 
 	acpi_processor_power_exit(pr);
 
-	sysfs_remove_link(&device->dev.kobj, "sysdev");
-
 	if (pr->cdev) {
 		sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
 		sysfs_remove_link(&pr->cdev->device.kobj, "device");
 		thermal_cooling_device_unregister(pr->cdev);
 		pr->cdev = NULL;
 	}
-
-	per_cpu(processors, pr->id) = NULL;
-	per_cpu(processor_device_array, pr->id) = NULL;
-	try_offline_node(cpu_to_node(pr->id));
-
-free:
-	free_cpumask_var(pr->throttling.shared_cpu_map);
-	kfree(pr);
-
 	return 0;
 }
 
-#ifdef CONFIG_ACPI_HOTPLUG_CPU
-/****************************************************************************
- * 	Acpi processor hotplug support 				       	    *
- ****************************************************************************/
-
-static int is_processor_present(acpi_handle handle)
-{
-	acpi_status status;
-	unsigned long long sta = 0;
-
-
-	status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
-
-	if (ACPI_SUCCESS(status) && (sta & ACPI_STA_DEVICE_PRESENT))
-		return 1;
-
-	/*
-	 * _STA is mandatory for a processor that supports hot plug
-	 */
-	if (status == AE_NOT_FOUND)
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
-				"Processor does not support hot plug\n"));
-	else
-		ACPI_EXCEPTION((AE_INFO, status,
-				"Processor Device is not present"));
-	return 0;
-}
-
-static void acpi_processor_hotplug_notify(acpi_handle handle,
-					  u32 event, void *data)
-{
-	struct acpi_device *device = NULL;
-	struct acpi_eject_event *ej_event = NULL;
-	u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
-	acpi_status status;
-	int result;
-
-	acpi_scan_lock_acquire();
-
-	switch (event) {
-	case ACPI_NOTIFY_BUS_CHECK:
-	case ACPI_NOTIFY_DEVICE_CHECK:
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
-		"Processor driver received %s event\n",
-		       (event == ACPI_NOTIFY_BUS_CHECK) ?
-		       "ACPI_NOTIFY_BUS_CHECK" : "ACPI_NOTIFY_DEVICE_CHECK"));
-
-		if (!is_processor_present(handle))
-			break;
-
-		if (!acpi_bus_get_device(handle, &device))
-			break;
-
-		result = acpi_bus_scan(handle);
-		if (result) {
-			acpi_handle_err(handle, "Unable to add the device\n");
-			break;
-		}
-		result = acpi_bus_get_device(handle, &device);
-		if (result) {
-			acpi_handle_err(handle, "Missing device object\n");
-			break;
-		}
-		ost_code = ACPI_OST_SC_SUCCESS;
-		break;
-
-	case ACPI_NOTIFY_EJECT_REQUEST:
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
-				  "received ACPI_NOTIFY_EJECT_REQUEST\n"));
-
-		if (acpi_bus_get_device(handle, &device)) {
-			acpi_handle_err(handle,
-				"Device don't exist, dropping EJECT\n");
-			break;
-		}
-		if (!acpi_driver_data(device)) {
-			acpi_handle_err(handle,
-				"Driver data is NULL, dropping EJECT\n");
-			break;
-		}
-
-		ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL);
-		if (!ej_event) {
-			acpi_handle_err(handle, "No memory, dropping EJECT\n");
-			break;
-		}
-
-		get_device(&device->dev);
-		ej_event->device = device;
-		ej_event->event = ACPI_NOTIFY_EJECT_REQUEST;
-		/* The eject is carried out asynchronously. */
-		status = acpi_os_hotplug_execute(acpi_bus_hot_remove_device,
-						 ej_event);
-		if (ACPI_FAILURE(status)) {
-			put_device(&device->dev);
-			kfree(ej_event);
-			break;
-		}
-		goto out;
-
-	default:
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
-				  "Unsupported event [0x%x]\n", event));
-
-		/* non-hotplug event; possibly handled by other handler */
-		goto out;
-	}
-
-	/* Inform firmware that the hotplug operation has completed */
-	(void) acpi_evaluate_hotplug_ost(handle, event, ost_code, NULL);
-
- out:
-	acpi_scan_lock_release();
-}
-
-static acpi_status is_processor_device(acpi_handle handle)
-{
-	struct acpi_device_info *info;
-	char *hid;
-	acpi_status status;
-
-	status = acpi_get_object_info(handle, &info);
-	if (ACPI_FAILURE(status))
-		return status;
-
-	if (info->type == ACPI_TYPE_PROCESSOR) {
-		kfree(info);
-		return AE_OK;	/* found a processor object */
-	}
-
-	if (!(info->valid & ACPI_VALID_HID)) {
-		kfree(info);
-		return AE_ERROR;
-	}
-
-	hid = info->hardware_id.string;
-	if ((hid == NULL) || strcmp(hid, ACPI_PROCESSOR_DEVICE_HID)) {
-		kfree(info);
-		return AE_ERROR;
-	}
-
-	kfree(info);
-	return AE_OK;	/* found a processor device object */
-}
-
-static acpi_status
-processor_walk_namespace_cb(acpi_handle handle,
-			    u32 lvl, void *context, void **rv)
-{
-	acpi_status status;
-	int *action = context;
-
-	status = is_processor_device(handle);
-	if (ACPI_FAILURE(status))
-		return AE_OK;	/* not a processor; continue to walk */
-
-	switch (*action) {
-	case INSTALL_NOTIFY_HANDLER:
-		acpi_install_notify_handler(handle,
-					    ACPI_SYSTEM_NOTIFY,
-					    acpi_processor_hotplug_notify,
-					    NULL);
-		break;
-	case UNINSTALL_NOTIFY_HANDLER:
-		acpi_remove_notify_handler(handle,
-					   ACPI_SYSTEM_NOTIFY,
-					   acpi_processor_hotplug_notify);
-		break;
-	default:
-		break;
-	}
-
-	/* found a processor; skip walking underneath */
-	return AE_CTRL_DEPTH;
-}
-
-static acpi_status acpi_processor_hotadd_init(struct acpi_processor *pr)
-{
-	acpi_handle handle = pr->handle;
-
-	if (!is_processor_present(handle)) {
-		return AE_ERROR;
-	}
-
-	if (acpi_map_lsapic(handle, &pr->id))
-		return AE_ERROR;
-
-	if (arch_register_cpu(pr->id)) {
-		acpi_unmap_lsapic(pr->id);
-		return AE_ERROR;
-	}
-
-	/* CPU got hot-plugged, but cpu_data is not initialized yet
-	 * Set flag to delay cpu_idle/throttling initialization
-	 * in:
-	 * acpi_processor_add()
-	 *   acpi_processor_get_info()
-	 * and do it when the CPU gets online the first time
-	 * TBD: Cleanup above functions and try to do this more elegant.
-	 */
-	pr_info("CPU %d got hotplugged\n", pr->id);
-	pr->flags.need_hotplug_init = 1;
-
-	return AE_OK;
-}
-
-static int acpi_processor_handle_eject(struct acpi_processor *pr)
-{
-	if (cpu_online(pr->id))
-		cpu_down(pr->id);
-
-	get_online_cpus();
-	/*
-	 * The cpu might become online again at this point. So we check whether
-	 * the cpu has been onlined or not. If the cpu became online, it means
-	 * that someone wants to use the cpu. So acpi_processor_handle_eject()
-	 * returns -EAGAIN.
-	 */
-	if (unlikely(cpu_online(pr->id))) {
-		put_online_cpus();
-		pr_warn("Failed to remove CPU %d, because other task "
-			"brought the CPU back online\n", pr->id);
-		return -EAGAIN;
-	}
-	arch_unregister_cpu(pr->id);
-	acpi_unmap_lsapic(pr->id);
-	put_online_cpus();
-	return (0);
-}
-#else
-static acpi_status acpi_processor_hotadd_init(struct acpi_processor *pr)
-{
-	return AE_ERROR;
-}
-static int acpi_processor_handle_eject(struct acpi_processor *pr)
-{
-	return (-EINVAL);
-}
-#endif
-
-static
-void acpi_processor_install_hotplug_notify(void)
-{
-#ifdef CONFIG_ACPI_HOTPLUG_CPU
-	int action = INSTALL_NOTIFY_HANDLER;
-	acpi_walk_namespace(ACPI_TYPE_ANY,
-			    ACPI_ROOT_OBJECT,
-			    ACPI_UINT32_MAX,
-			    processor_walk_namespace_cb, NULL, &action, NULL);
-#endif
-	register_hotcpu_notifier(&acpi_cpu_notifier);
-}
-
-static
-void acpi_processor_uninstall_hotplug_notify(void)
-{
-#ifdef CONFIG_ACPI_HOTPLUG_CPU
-	int action = UNINSTALL_NOTIFY_HANDLER;
-	acpi_walk_namespace(ACPI_TYPE_ANY,
-			    ACPI_ROOT_OBJECT,
-			    ACPI_UINT32_MAX,
-			    processor_walk_namespace_cb, NULL, &action, NULL);
-#endif
-	unregister_hotcpu_notifier(&acpi_cpu_notifier);
-}
-
 /*
  * We keep the driver loaded even when ACPI is not running.
  * This is needed for the powernow-k8 driver, that works even without
  * ACPI, but needs symbols from this driver
  */
 
-static int __init acpi_processor_init(void)
+static int __init acpi_processor_driver_init(void)
 {
 	int result = 0;
 
 	if (acpi_disabled)
 		return 0;
 
-	result = acpi_bus_register_driver(&acpi_processor_driver);
+	result = driver_register(&acpi_processor_driver);
 	if (result < 0)
 		return result;
 
 	acpi_processor_syscore_init();
-
-	acpi_processor_install_hotplug_notify();
-
+	register_hotcpu_notifier(&acpi_cpu_notifier);
 	acpi_thermal_cpufreq_init();
-
 	acpi_processor_ppc_init();
-
 	acpi_processor_throttling_init();
-
 	return 0;
 }
 
-static void __exit acpi_processor_exit(void)
+static void __exit acpi_processor_driver_exit(void)
 {
 	if (acpi_disabled)
 		return;
 
 	acpi_processor_ppc_exit();
-
 	acpi_thermal_cpufreq_exit();
-
-	acpi_processor_uninstall_hotplug_notify();
-
+	unregister_hotcpu_notifier(&acpi_cpu_notifier);
 	acpi_processor_syscore_exit();
-
-	acpi_bus_unregister_driver(&acpi_processor_driver);
-
-	return;
+	driver_unregister(&acpi_processor_driver);
 }
 
-module_init(acpi_processor_init);
-module_exit(acpi_processor_exit);
+module_init(acpi_processor_driver_init);
+module_exit(acpi_processor_driver_exit);
 
 MODULE_ALIAS("processor");
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 27da63061e11..db118b1ad3e8 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -27,6 +27,12 @@ extern struct acpi_device *acpi_root;
 
 #define ACPI_IS_ROOT_DEVICE(device)    (!(device)->parent)
 
+/*
+ * If set, devices will be hot-removed even if they cannot be put offline
+ * gracefully (from the kernel's standpoint).
+ */
+bool acpi_force_hot_remove;
+
 static const char *dummy_hid = "device";
 
 static LIST_HEAD(acpi_device_list);
@@ -120,12 +126,78 @@ acpi_device_modalias_show(struct device *dev, struct device_attribute *attr, cha
 }
 static DEVICE_ATTR(modalias, 0444, acpi_device_modalias_show, NULL);
 
+static acpi_status acpi_bus_offline_companions(acpi_handle handle, u32 lvl,
+					       void *data, void **ret_p)
+{
+	struct acpi_device *device = NULL;
+	struct acpi_device_physical_node *pn;
+	bool second_pass = (bool)data;
+	acpi_status status = AE_OK;
+
+	if (acpi_bus_get_device(handle, &device))
+		return AE_OK;
+
+	mutex_lock(&device->physical_node_lock);
+
+	list_for_each_entry(pn, &device->physical_node_list, node) {
+		int ret;
+
+		if (second_pass) {
+			/* Skip devices offlined by the first pass. */
+			if (pn->put_online)
+				continue;
+		} else {
+			pn->put_online = false;
+		}
+		ret = device_offline(pn->dev);
+		if (acpi_force_hot_remove)
+			continue;
+
+		if (ret >= 0) {
+			pn->put_online = !ret;
+		} else {
+			*ret_p = pn->dev;
+			if (second_pass) {
+				status = AE_ERROR;
+				break;
+			}
+		}
+	}
+
+	mutex_unlock(&device->physical_node_lock);
+
+	return status;
+}
+
+static acpi_status acpi_bus_online_companions(acpi_handle handle, u32 lvl,
+					      void *data, void **ret_p)
+{
+	struct acpi_device *device = NULL;
+	struct acpi_device_physical_node *pn;
+
+	if (acpi_bus_get_device(handle, &device))
+		return AE_OK;
+
+	mutex_lock(&device->physical_node_lock);
+
+	list_for_each_entry(pn, &device->physical_node_list, node)
+		if (pn->put_online) {
+			device_online(pn->dev);
+			pn->put_online = false;
+		}
+
+	mutex_unlock(&device->physical_node_lock);
+
+	return AE_OK;
+}
+
 static int acpi_scan_hot_remove(struct acpi_device *device)
 {
 	acpi_handle handle = device->handle;
 	acpi_handle not_used;
 	struct acpi_object_list arg_list;
 	union acpi_object arg;
+	struct device *errdev;
 	acpi_status status;
 	unsigned long long sta;
 
@@ -136,10 +208,53 @@ static int acpi_scan_hot_remove(struct acpi_device *device)
 		return -EINVAL;
 	}
 
+	lock_device_hotplug();
+
+	/*
+	 * Carry out two passes here and ignore errors in the first pass,
+	 * because if the devices in question are memory blocks and
+	 * CONFIG_MEMCG is set, one of the blocks may hold data structures
+	 * that the other blocks depend on, but it is not known in advance which
+	 * block holds them.
+	 *
+	 * If the first pass is successful, the second one isn't needed, though.
+	 */
+	errdev = NULL;
+	acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
+			    NULL, acpi_bus_offline_companions,
+			    (void *)false, (void **)&errdev);
+	acpi_bus_offline_companions(handle, 0, (void *)false, (void **)&errdev);
+	if (errdev) {
+		errdev = NULL;
+		acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
+				    NULL, acpi_bus_offline_companions,
+				    (void *)true , (void **)&errdev);
+		if (!errdev || acpi_force_hot_remove)
+			acpi_bus_offline_companions(handle, 0, (void *)true,
+						    (void **)&errdev);
+
+		if (errdev && !acpi_force_hot_remove) {
+			dev_warn(errdev, "Offline failed.\n");
+			acpi_bus_online_companions(handle, 0, NULL, NULL);
+			acpi_walk_namespace(ACPI_TYPE_ANY, handle,
+					    ACPI_UINT32_MAX,
+					    acpi_bus_online_companions, NULL,
+					    NULL, NULL);
+
+			unlock_device_hotplug();
+
+			put_device(&device->dev);
+			return -EBUSY;
+		}
+	}
+
 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 		"Hot-removing device %s...\n", dev_name(&device->dev)));
 
 	acpi_bus_trim(device);
+
+	unlock_device_hotplug();
+
 	/* Device node has been unregistered. */
 	put_device(&device->dev);
 	device = NULL;
@@ -236,6 +351,7 @@ static void acpi_scan_bus_device_check(acpi_handle handle, u32 ost_source)
 	int error;
 
 	mutex_lock(&acpi_scan_lock);
+	lock_device_hotplug();
 
 	acpi_bus_get_device(handle, &device);
 	if (device) {
@@ -259,6 +375,7 @@ static void acpi_scan_bus_device_check(acpi_handle handle, u32 ost_source)
 		kobject_uevent(&device->dev.kobj, KOBJ_ONLINE);
 
  out:
+	unlock_device_hotplug();
 	acpi_evaluate_hotplug_ost(handle, ost_source, ost_code, NULL);
 	mutex_unlock(&acpi_scan_lock);
 }
@@ -952,7 +1069,6 @@ int acpi_device_add(struct acpi_device *device,
 		printk(KERN_ERR PREFIX "Error creating sysfs interface for device %s\n",
 		       dev_name(&device->dev));
 
-	device->removal_type = ACPI_BUS_REMOVAL_NORMAL;
 	return 0;
 
  err:
@@ -1939,7 +2055,6 @@ static acpi_status acpi_bus_device_detach(acpi_handle handle, u32 lvl_not_used,
 	if (!acpi_bus_get_device(handle, &device)) {
 		struct acpi_scan_handler *dev_handler = device->handler;
 
-		device->removal_type = ACPI_BUS_REMOVAL_EJECT;
 		if (dev_handler) {
 			if (dev_handler->detach)
 				dev_handler->detach(device);
@@ -2038,6 +2153,7 @@ int __init acpi_scan_init(void)
 
 	acpi_pci_root_init();
 	acpi_pci_link_init();
+	acpi_processor_init();
 	acpi_platform_init();
 	acpi_lpss_init();
 	acpi_container_init();
diff --git a/drivers/acpi/sysfs.c b/drivers/acpi/sysfs.c
index fcae5fa2e1b3..5c5d1624fa2c 100644
--- a/drivers/acpi/sysfs.c
+++ b/drivers/acpi/sysfs.c
@@ -780,6 +780,33 @@ void acpi_sysfs_add_hotplug_profile(struct acpi_hotplug_profile *hotplug,
 	pr_err(PREFIX "Unable to add hotplug profile '%s'\n", name);
 }
 
+static ssize_t force_remove_show(struct kobject *kobj,
+				 struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", !!acpi_force_hot_remove);
+}
+
+static ssize_t force_remove_store(struct kobject *kobj,
+				  struct kobj_attribute *attr,
+				  const char *buf, size_t size)
+{
+	bool val;
+	int ret;
+
+	ret = strtobool(buf, &val);
+	if (ret < 0)
+		return ret;
+
+	lock_device_hotplug();
+	acpi_force_hot_remove = val;
+	unlock_device_hotplug();
+	return size;
+}
+
+static const struct kobj_attribute force_remove_attr =
+	__ATTR(force_remove, S_IRUGO | S_IWUSR, force_remove_show,
+	       force_remove_store);
+
 int __init acpi_sysfs_init(void)
 {
 	int result;
@@ -789,6 +816,10 @@ int __init acpi_sysfs_init(void)
 		return result;
 
 	hotplug_kobj = kobject_create_and_add("hotplug", acpi_kobj);
+	result = sysfs_create_file(hotplug_kobj, &force_remove_attr.attr);
+	if (result)
+		return result;
+
 	result = sysfs_create_file(acpi_kobj, &pm_profile_attr.attr);
 	return result;
 }
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 2499cefdcdf2..2166f34b7d84 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -403,6 +403,36 @@ static ssize_t store_uevent(struct device *dev, struct device_attribute *attr,
 static struct device_attribute uevent_attr =
 	__ATTR(uevent, S_IRUGO | S_IWUSR, show_uevent, store_uevent);
 
+static ssize_t show_online(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	bool val;
+
+	lock_device_hotplug();
+	val = !dev->offline;
+	unlock_device_hotplug();
+	return sprintf(buf, "%u\n", val);
+}
+
+static ssize_t store_online(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	bool val;
+	int ret;
+
+	ret = strtobool(buf, &val);
+	if (ret < 0)
+		return ret;
+
+	lock_device_hotplug();
+	ret = val ? device_online(dev) : device_offline(dev);
+	unlock_device_hotplug();
+	return ret < 0 ? ret : count;
+}
+
+static struct device_attribute online_attr =
+	__ATTR(online, S_IRUGO | S_IWUSR, show_online, store_online);
+
 static int device_add_attributes(struct device *dev,
 				 struct device_attribute *attrs)
 {
@@ -516,6 +546,12 @@ static int device_add_attrs(struct device *dev)
 	if (error)
 		goto err_remove_type_groups;
 
+	if (device_supports_offline(dev) && !dev->offline_disabled) {
+		error = device_create_file(dev, &online_attr);
+		if (error)
+			goto err_remove_type_groups;
+	}
+
 	return 0;
 
  err_remove_type_groups:
@@ -536,6 +572,7 @@ static void device_remove_attrs(struct device *dev)
 	struct class *class = dev->class;
 	const struct device_type *type = dev->type;
 
+	device_remove_file(dev, &online_attr);
 	device_remove_groups(dev, dev->groups);
 
 	if (type)
@@ -1433,6 +1470,99 @@ EXPORT_SYMBOL_GPL(put_device);
 EXPORT_SYMBOL_GPL(device_create_file);
 EXPORT_SYMBOL_GPL(device_remove_file);
 
+static DEFINE_MUTEX(device_hotplug_lock);
+
+void lock_device_hotplug(void)
+{
+	mutex_lock(&device_hotplug_lock);
+}
+
+void unlock_device_hotplug(void)
+{
+	mutex_unlock(&device_hotplug_lock);
+}
+
+static int device_check_offline(struct device *dev, void *not_used)
+{
+	int ret;
+
+	ret = device_for_each_child(dev, NULL, device_check_offline);
+	if (ret)
+		return ret;
+
+	return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
+}
+
+/**
+ * device_offline - Prepare the device for hot-removal.
+ * @dev: Device to be put offline.
+ *
+ * Execute the device bus type's .offline() callback, if present, to prepare
+ * the device for a subsequent hot-removal.  If that succeeds, the device must
+ * not be used until either it is removed or its bus type's .online() callback
+ * is executed.
+ *
+ * Call under device_hotplug_lock.
+ */
+int device_offline(struct device *dev)
+{
+	int ret;
+
+	if (dev->offline_disabled)
+		return -EPERM;
+
+	ret = device_for_each_child(dev, NULL, device_check_offline);
+	if (ret)
+		return ret;
+
+	device_lock(dev);
+	if (device_supports_offline(dev)) {
+		if (dev->offline) {
+			ret = 1;
+		} else {
+			ret = dev->bus->offline(dev);
+			if (!ret) {
+				kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
+				dev->offline = true;
+			}
+		}
+	}
+	device_unlock(dev);
+
+	return ret;
+}
+
+/**
+ * device_online - Put the device back online after successful device_offline().
+ * @dev: Device to be put back online.
+ *
+ * If device_offline() has been successfully executed for @dev, but the device
+ * has not been removed subsequently, execute its bus type's .online() callback
+ * to indicate that the device can be used again.
+ *
+ * Call under device_hotplug_lock.
+ */
+int device_online(struct device *dev)
+{
+	int ret = 0;
+
+	device_lock(dev);
+	if (device_supports_offline(dev)) {
+		if (dev->offline) {
+			ret = dev->bus->online(dev);
+			if (!ret) {
+				kobject_uevent(&dev->kobj, KOBJ_ONLINE);
+				dev->offline = false;
+			}
+		} else {
+			ret = 1;
+		}
+	}
+	device_unlock(dev);
+
+	return ret;
+}
+
 struct root_device {
 	struct device dev;
 	struct module *owner;
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 3d48fc887ef4..1d110dc6f0c1 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -13,17 +13,21 @@
 #include <linux/gfp.h>
 #include <linux/slab.h>
 #include <linux/percpu.h>
+#include <linux/acpi.h>
 
 #include "base.h"
 
-struct bus_type cpu_subsys = {
-	.name = "cpu",
-	.dev_name = "cpu",
-};
-EXPORT_SYMBOL_GPL(cpu_subsys);
-
 static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
 
+static int cpu_subsys_match(struct device *dev, struct device_driver *drv)
+{
+	/* ACPI style match is the only one that may succeed. */
+	if (acpi_driver_match_device(dev, drv))
+		return 1;
+
+	return 0;
+}
+
 #ifdef CONFIG_HOTPLUG_CPU
 static void change_cpu_under_node(struct cpu *cpu,
 			unsigned int from_nid, unsigned int to_nid)
@@ -34,69 +38,45 @@ static void change_cpu_under_node(struct cpu *cpu,
 	cpu->node_id = to_nid;
 }
 
-static ssize_t show_online(struct device *dev,
-			   struct device_attribute *attr,
-			   char *buf)
+static int __ref cpu_subsys_online(struct device *dev)
 {
 	struct cpu *cpu = container_of(dev, struct cpu, dev);
+	int cpuid = dev->id;
+	int from_nid, to_nid;
+	int ret;
 
-	return sprintf(buf, "%u\n", !!cpu_online(cpu->dev.id));
+	cpu_hotplug_driver_lock();
+
+	from_nid = cpu_to_node(cpuid);
+	ret = cpu_up(cpuid);
+	/*
+	 * When hot adding memory to memoryless node and enabling a cpu
+	 * on the node, node number of the cpu may internally change.
+	 */
+	to_nid = cpu_to_node(cpuid);
+	if (from_nid != to_nid)
+		change_cpu_under_node(cpu, from_nid, to_nid);
+
+	cpu_hotplug_driver_unlock();
+	return ret;
 }
 
-static ssize_t __ref store_online(struct device *dev,
-				  struct device_attribute *attr,
-				  const char *buf, size_t count)
+static int cpu_subsys_offline(struct device *dev)
 {
-	struct cpu *cpu = container_of(dev, struct cpu, dev);
-	int cpuid = cpu->dev.id;
-	int from_nid, to_nid;
-	ssize_t ret;
+	int ret;
 
 	cpu_hotplug_driver_lock();
-	switch (buf[0]) {
-	case '0':
-		ret = cpu_down(cpuid);
-		if (!ret)
-			kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
-		break;
-	case '1':
-		from_nid = cpu_to_node(cpuid);
-		ret = cpu_up(cpuid);
-
-		/*
-		 * When hot adding memory to memoryless node and enabling a cpu
-		 * on the node, node number of the cpu may internally change.
-		 */
-		to_nid = cpu_to_node(cpuid);
-		if (from_nid != to_nid)
-			change_cpu_under_node(cpu, from_nid, to_nid);
-
-		if (!ret)
-			kobject_uevent(&dev->kobj, KOBJ_ONLINE);
-		break;
-	default:
-		ret = -EINVAL;
-	}
+	ret = cpu_down(dev->id);
 	cpu_hotplug_driver_unlock();
-
-	if (ret >= 0)
-		ret = count;
 	return ret;
 }
-static DEVICE_ATTR(online, 0644, show_online, store_online);
 
-static void __cpuinit register_cpu_control(struct cpu *cpu)
-{
-	device_create_file(&cpu->dev, &dev_attr_online);
-}
 void unregister_cpu(struct cpu *cpu)
 {
 	int logical_cpu = cpu->dev.id;
 
 	unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu));
 
-	device_remove_file(&cpu->dev, &dev_attr_online);
-
 	device_unregister(&cpu->dev);
 	per_cpu(cpu_sys_devices, logical_cpu) = NULL;
 	return;
@@ -123,12 +103,19 @@ static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);
 static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store);
 #endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
 
-#else /* ... !CONFIG_HOTPLUG_CPU */
-static inline void register_cpu_control(struct cpu *cpu)
-{
-}
 #endif /* CONFIG_HOTPLUG_CPU */
 
+struct bus_type cpu_subsys = {
+	.name = "cpu",
+	.dev_name = "cpu",
+	.match = cpu_subsys_match,
+#ifdef CONFIG_HOTPLUG_CPU
+	.online = cpu_subsys_online,
+	.offline = cpu_subsys_offline,
+#endif
+};
+EXPORT_SYMBOL_GPL(cpu_subsys);
+
 #ifdef CONFIG_KEXEC
 #include <linux/kexec.h>
 
@@ -277,12 +264,12 @@ int __cpuinit register_cpu(struct cpu *cpu, int num)
 	cpu->dev.id = num;
 	cpu->dev.bus = &cpu_subsys;
 	cpu->dev.release = cpu_device_release;
+	cpu->dev.offline_disabled = !cpu->hotpluggable;
+	cpu->dev.offline = !cpu_online(num);
 #ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
 	cpu->dev.bus->uevent = arch_cpu_uevent;
 #endif
 	error = device_register(&cpu->dev);
-	if (!error && cpu->hotpluggable)
-		register_cpu_control(cpu);
 	if (!error)
 		per_cpu(cpu_sys_devices, num) = &cpu->dev;
 	if (!error)
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 14f8a6954da0..4ebf97f99fae 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -37,9 +37,14 @@ static inline int base_memory_block_id(int section_nr)
 	return section_nr / sections_per_block;
 }
 
+static int memory_subsys_online(struct device *dev);
+static int memory_subsys_offline(struct device *dev);
+
 static struct bus_type memory_subsys = {
 	.name = MEMORY_CLASS_NAME,
 	.dev_name = MEMORY_CLASS_NAME,
+	.online = memory_subsys_online,
+	.offline = memory_subsys_offline,
 };
 
 static BLOCKING_NOTIFIER_HEAD(memory_chain);
@@ -88,6 +93,7 @@ int register_memory(struct memory_block *memory)
 	memory->dev.bus = &memory_subsys;
 	memory->dev.id = memory->start_section_nr / sections_per_block;
 	memory->dev.release = memory_block_release;
+	memory->dev.offline = memory->state == MEM_OFFLINE;
 
 	error = device_register(&memory->dev);
 	return error;
@@ -278,33 +284,64 @@ static int __memory_block_change_state(struct memory_block *mem,
 {
 	int ret = 0;
 
-	if (mem->state != from_state_req) {
-		ret = -EINVAL;
-		goto out;
-	}
+	if (mem->state != from_state_req)
+		return -EINVAL;
 
 	if (to_state == MEM_OFFLINE)
 		mem->state = MEM_GOING_OFFLINE;
 
 	ret = memory_block_action(mem->start_section_nr, to_state, online_type);
+	mem->state = ret ? from_state_req : to_state;
+	return ret;
+}
 
-	if (ret) {
-		mem->state = from_state_req;
-		goto out;
-	}
+static int memory_subsys_online(struct device *dev)
+{
+	struct memory_block *mem = container_of(dev, struct memory_block, dev);
+	int ret;
 
-	mem->state = to_state;
-	switch (mem->state) {
-	case MEM_OFFLINE:
-		kobject_uevent(&mem->dev.kobj, KOBJ_OFFLINE);
-		break;
-	case MEM_ONLINE:
-		kobject_uevent(&mem->dev.kobj, KOBJ_ONLINE);
-		break;
-	default:
-		break;
+	mutex_lock(&mem->state_mutex);
+
+	ret = mem->state == MEM_ONLINE ? 0 :
+		__memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE,
+					    ONLINE_KEEP);
+
+	mutex_unlock(&mem->state_mutex);
+	return ret;
+}
+
+static int memory_subsys_offline(struct device *dev)
+{
+	struct memory_block *mem = container_of(dev, struct memory_block, dev);
+	int ret;
+
+	mutex_lock(&mem->state_mutex);
+
+	ret = mem->state == MEM_OFFLINE ? 0 :
+		__memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE, -1);
+
+	mutex_unlock(&mem->state_mutex);
+	return ret;
+}
+
+static int __memory_block_change_state_uevent(struct memory_block *mem,
+		unsigned long to_state, unsigned long from_state_req,
+		int online_type)
+{
+	int ret = __memory_block_change_state(mem, to_state, from_state_req,
+					      online_type);
+	if (!ret) {
+		switch (mem->state) {
+		case MEM_OFFLINE:
+			kobject_uevent(&mem->dev.kobj, KOBJ_OFFLINE);
+			break;
+		case MEM_ONLINE:
+			kobject_uevent(&mem->dev.kobj, KOBJ_ONLINE);
+			break;
+		default:
+			break;
+		}
 	}
-out:
 	return ret;
 }
 
@@ -315,8 +352,8 @@ static int memory_block_change_state(struct memory_block *mem,
 	int ret;
 
 	mutex_lock(&mem->state_mutex);
-	ret = __memory_block_change_state(mem, to_state, from_state_req,
-					  online_type);
+	ret = __memory_block_change_state_uevent(mem, to_state, from_state_req,
+						 online_type);
 	mutex_unlock(&mem->state_mutex);
 
 	return ret;
@@ -326,22 +363,34 @@ store_mem_state(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t count)
 {
 	struct memory_block *mem;
+	bool offline;
 	int ret = -EINVAL;
 
 	mem = container_of(dev, struct memory_block, dev);
 
-	if (!strncmp(buf, "online_kernel", min_t(int, count, 13)))
+	lock_device_hotplug();
+
+	if (!strncmp(buf, "online_kernel", min_t(int, count, 13))) {
+		offline = false;
 		ret = memory_block_change_state(mem, MEM_ONLINE,
 						MEM_OFFLINE, ONLINE_KERNEL);
-	else if (!strncmp(buf, "online_movable", min_t(int, count, 14)))
+	} else if (!strncmp(buf, "online_movable", min_t(int, count, 14))) {
+		offline = false;
 		ret = memory_block_change_state(mem, MEM_ONLINE,
 						MEM_OFFLINE, ONLINE_MOVABLE);
-	else if (!strncmp(buf, "online", min_t(int, count, 6)))
+	} else if (!strncmp(buf, "online", min_t(int, count, 6))) {
+		offline = false;
 		ret = memory_block_change_state(mem, MEM_ONLINE,
 						MEM_OFFLINE, ONLINE_KEEP);
-	else if(!strncmp(buf, "offline", min_t(int, count, 7)))
+	} else if(!strncmp(buf, "offline", min_t(int, count, 7))) {
+		offline = true;
 		ret = memory_block_change_state(mem, MEM_OFFLINE,
 						MEM_ONLINE, -1);
+	}
+	if (!ret)
+		dev->offline = offline;
+
+	unlock_device_hotplug();
 
 	if (ret)
 		return ret;
@@ -679,21 +728,6 @@ int unregister_memory_section(struct mem_section *section)
 }
 #endif /* CONFIG_MEMORY_HOTREMOVE */
 
-/*
- * offline one memory block. If the memory block has been offlined, do nothing.
- */
-int offline_memory_block(struct memory_block *mem)
-{
-	int ret = 0;
-
-	mutex_lock(&mem->state_mutex);
-	if (mem->state != MEM_OFFLINE)
-		ret = __memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE, -1);
-	mutex_unlock(&mem->state_mutex);
-
-	return ret;
-}
-
 /* return true if the memory block is offlined, otherwise, return false */
 bool is_memblock_offlined(struct memory_block *mem)
 {
diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index edc089e9d0c4..b8efacf01d69 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -1034,4 +1034,11 @@ static const struct x86_cpu_id acpi_cpufreq_ids[] = {
 };
 MODULE_DEVICE_TABLE(x86cpu, acpi_cpufreq_ids);
 
+static const struct acpi_device_id processor_device_ids[] = {
+	{ACPI_PROCESSOR_OBJECT_HID, },
+	{ACPI_PROCESSOR_DEVICE_HID, },
+	{},
+};
+MODULE_DEVICE_TABLE(acpi, processor_device_ids);
+
 MODULE_ALIAS("acpi");
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index c13c919ab99e..cf0817a555e4 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -63,13 +63,6 @@ acpi_get_physical_device_location(acpi_handle handle, struct acpi_pld_info **pld
 #define ACPI_BUS_FILE_ROOT	"acpi"
 extern struct proc_dir_entry *acpi_root_dir;
 
-enum acpi_bus_removal_type {
-	ACPI_BUS_REMOVAL_NORMAL = 0,
-	ACPI_BUS_REMOVAL_EJECT,
-	ACPI_BUS_REMOVAL_SUPRISE,
-	ACPI_BUS_REMOVAL_TYPE_COUNT
-};
-
 enum acpi_bus_device_type {
 	ACPI_BUS_TYPE_DEVICE = 0,
 	ACPI_BUS_TYPE_POWER,
@@ -286,6 +279,7 @@ struct acpi_device_physical_node {
 	u8 node_id;
 	struct list_head node;
 	struct device *dev;
+	bool put_online:1;
 };
 
 /* set maximum of physical nodes to 32 for expansibility */
@@ -310,7 +304,6 @@ struct acpi_device {
 	struct acpi_driver *driver;
 	void *driver_data;
 	struct device dev;
-	enum acpi_bus_removal_type removal_type;	/* indicate for different removal type */
 	u8 physical_node_count;
 	struct list_head physical_node_list;
 	struct mutex physical_node_lock;
diff --git a/include/acpi/processor.h b/include/acpi/processor.h
index ea69367fdd3b..66096d06925e 100644
--- a/include/acpi/processor.h
+++ b/include/acpi/processor.h
@@ -6,6 +6,10 @@
 #include <linux/thermal.h>
 #include <asm/acpi.h>
 
+#define ACPI_PROCESSOR_CLASS		"processor"
+#define ACPI_PROCESSOR_DEVICE_NAME	"Processor"
+#define ACPI_PROCESSOR_DEVICE_HID	"ACPI0007"
+
 #define ACPI_PROCESSOR_BUSY_METRIC	10
 
 #define ACPI_PROCESSOR_MAX_POWER	8
@@ -207,6 +211,7 @@ struct acpi_processor {
 	struct acpi_processor_throttling throttling;
 	struct acpi_processor_limit limit;
 	struct thermal_cooling_device *cdev;
+	struct device *dev; /* Processor device. */
 };
 
 struct acpi_processor_errata {
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 17b5b5967641..353ba256f368 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -352,8 +352,7 @@ extern acpi_status acpi_pci_osc_control_set(acpi_handle handle,
 
 /* Enable _OST when all relevant hotplug operations are enabled */
 #if defined(CONFIG_ACPI_HOTPLUG_CPU) &&			\
-	(defined(CONFIG_ACPI_HOTPLUG_MEMORY) ||		\
-	 defined(CONFIG_ACPI_HOTPLUG_MEMORY_MODULE)) &&	\
+	defined(CONFIG_ACPI_HOTPLUG_MEMORY) &&		\
 	defined(CONFIG_ACPI_CONTAINER)
 #define ACPI_HOTPLUG_OST
 #endif
diff --git a/include/linux/device.h b/include/linux/device.h
index c0a126125325..eeb33315514c 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -71,6 +71,10 @@ extern void bus_remove_file(struct bus_type *, struct bus_attribute *);
  *		the specific driver's probe to initial the matched device.
  * @remove:	Called when a device removed from this bus.
  * @shutdown:	Called at shut-down time to quiesce the device.
+ *
+ * @online:	Called to put the device back online (after offlining it).
+ * @offline:	Called to put the device offline for hot-removal. May fail.
+ *
  * @suspend:	Called when a device on this bus wants to go to sleep mode.
  * @resume:	Called to bring a device on this bus out of sleep mode.
  * @pm:		Power management operations of this bus, callback the specific
@@ -104,6 +108,9 @@ struct bus_type {
 	int (*remove)(struct device *dev);
 	void (*shutdown)(struct device *dev);
 
+	int (*online)(struct device *dev);
+	int (*offline)(struct device *dev);
+
 	int (*suspend)(struct device *dev, pm_message_t state);
 	int (*resume)(struct device *dev);
 
@@ -648,6 +655,8 @@ struct acpi_dev_node {
  * @release:	Callback to free the device after all references have
  * 		gone away. This should be set by the allocator of the
  * 		device (i.e. the bus driver that discovered the device).
+ * @offline_disabled: If set, the device is permanently online.
+ * @offline:	Set after successful invocation of bus type's .offline().
  *
  * At the lowest level, every device in a Linux system is represented by an
  * instance of struct device. The device structure contains the information
@@ -720,6 +729,9 @@ struct device {
 
 	void	(*release)(struct device *dev);
 	struct iommu_group	*iommu_group;
+
+	bool			offline_disabled:1;
+	bool			offline:1;
 };
 
 static inline struct device *kobj_to_dev(struct kobject *kobj)
@@ -856,6 +868,15 @@ extern const char *device_get_devnode(struct device *dev,
 extern void *dev_get_drvdata(const struct device *dev);
 extern int dev_set_drvdata(struct device *dev, void *data);
 
+static inline bool device_supports_offline(struct device *dev)
+{
+	return dev->bus && dev->bus->offline && dev->bus->online;
+}
+
+extern void lock_device_hotplug(void);
+extern void unlock_device_hotplug(void);
+extern int device_offline(struct device *dev);
+extern int device_online(struct device *dev);
 /*
  * Root device objects for grouping under /sys/devices
  */
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 3e622c610925..dd38e62b84d2 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -234,6 +234,8 @@ static inline void unlock_memory_hotplug(void) {}
 
 extern int is_mem_section_removable(unsigned long pfn, unsigned long nr_pages);
 extern void try_offline_node(int nid);
+extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
+extern void remove_memory(int nid, u64 start, u64 size);
 
 #else
 static inline int is_mem_section_removable(unsigned long pfn,
@@ -243,15 +245,23 @@ static inline int is_mem_section_removable(unsigned long pfn,
 }
 
 static inline void try_offline_node(int nid) {}
+
+static inline int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
+{
+	return -EINVAL;
+}
+
+static inline void remove_memory(int nid, u64 start, u64 size) {}
 #endif /* CONFIG_MEMORY_HOTREMOVE */
 
+extern int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
+		void *arg, int (*func)(struct memory_block *, void *));
 extern int mem_online_node(int nid);
 extern int add_memory(int nid, u64 start, u64 size);
 extern int arch_add_memory(int nid, u64 start, u64 size);
 extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
-extern int offline_memory_block(struct memory_block *mem);
 extern bool is_memblock_offlined(struct memory_block *mem);
-extern int remove_memory(int nid, u64 start, u64 size);
+extern void remove_memory(int nid, u64 start, u64 size);
 extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
 								int nr_pages);
 extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms);
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 1ad92b46753e..081b4d654ed6 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1621,6 +1621,7 @@ int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
 {
 	return __offline_pages(start_pfn, start_pfn + nr_pages, 120 * HZ);
 }
+#endif /* CONFIG_MEMORY_HOTREMOVE */
 
 /**
  * walk_memory_range - walks through all mem sections in [start_pfn, end_pfn)
@@ -1634,7 +1635,7 @@ int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
  *
  * Returns the return value of func.
  */
-static int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
+int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
 		void *arg, int (*func)(struct memory_block *, void *))
 {
 	struct memory_block *mem = NULL;
@@ -1671,24 +1672,7 @@ static int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
 	return 0;
 }
 
-/**
- * offline_memory_block_cb - callback function for offlining memory block
- * @mem: the memory block to be offlined
- * @arg: buffer to hold error msg
- *
- * Always return 0, and put the error msg in arg if any.
- */
-static int offline_memory_block_cb(struct memory_block *mem, void *arg)
-{
-	int *ret = arg;
-	int error = offline_memory_block(mem);
-
-	if (error != 0 && *ret == 0)
-		*ret = error;
-
-	return 0;
-}
-
+#ifdef CONFIG_MEMORY_HOTREMOVE
 static int is_memblock_offlined_cb(struct memory_block *mem, void *arg)
 {
 	int ret = !is_memblock_offlined(mem);
@@ -1814,54 +1798,22 @@ void try_offline_node(int nid)
 }
 EXPORT_SYMBOL(try_offline_node);
 
-int __ref remove_memory(int nid, u64 start, u64 size)
+void __ref remove_memory(int nid, u64 start, u64 size)
 {
-	unsigned long start_pfn, end_pfn;
-	int ret = 0;
-	int retry = 1;
-
-	start_pfn = PFN_DOWN(start);
-	end_pfn = PFN_UP(start + size - 1);
-
-	/*
-	 * When CONFIG_MEMCG is on, one memory block may be used by other
-	 * blocks to store page cgroup when onlining pages. But we don't know
-	 * in what order pages are onlined. So we iterate twice to offline
-	 * memory:
-	 * 1st iterate: offline every non primary memory block.
-	 * 2nd iterate: offline primary (i.e. first added) memory block.
-	 */
-repeat:
-	walk_memory_range(start_pfn, end_pfn, &ret,
-			  offline_memory_block_cb);
-	if (ret) {
-		if (!retry)
-			return ret;
-
-		retry = 0;
-		ret = 0;
-		goto repeat;
-	}
+	int ret;
 
 	lock_memory_hotplug();
 
 	/*
-	 * we have offlined all memory blocks like this:
-	 *   1. lock memory hotplug
-	 *   2. offline a memory block
-	 *   3. unlock memory hotplug
-	 *
-	 * repeat step1-3 to offline the memory block. All memory blocks
-	 * must be offlined before removing memory. But we don't hold the
-	 * lock in the whole operation. So we should check whether all
-	 * memory blocks are offlined.
+	 * All memory blocks must be offlined before removing memory.  Check
+	 * whether all memory blocks in question are offline and trigger a BUG()
+	 * if this is not the case.
 	 */
-
-	ret = walk_memory_range(start_pfn, end_pfn, NULL,
+	ret = walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1), NULL,
 				is_memblock_offlined_cb);
 	if (ret) {
 		unlock_memory_hotplug();
-		return ret;
+		BUG();
 	}
 
 	/* remove memmap entry */
@@ -1872,17 +1824,6 @@ repeat:
 	try_offline_node(nid);
 
 	unlock_memory_hotplug();
-
-	return 0;
 }
-#else
-int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
-{
-	return -EINVAL;
-}
-int remove_memory(int nid, u64 start, u64 size)
-{
-	return -EINVAL;
-}
-#endif /* CONFIG_MEMORY_HOTREMOVE */
 EXPORT_SYMBOL_GPL(remove_memory);
+#endif /* CONFIG_MEMORY_HOTREMOVE */