Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6

* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6: (31 commits)
  driver core: Display error codes when class suspend fails
  Driver core: Add section count to memory_block struct
  Driver core: Add mutex for adding/removing memory blocks
  Driver core: Move find_memory_block routine
  hpilo: Despecificate driver from iLO generation
  driver core: Convert link_mem_sections to use find_memory_block_hinted.
  driver core: Introduce find_memory_block_hinted which utilizes kset_find_obj_hinted.
  kobject: Introduce kset_find_obj_hinted.
  driver core: fix build for CONFIG_BLOCK not enabled
  driver-core: base: change to new flag variable
  sysfs: only access bin file vm_ops with the active lock
  sysfs: Fail bin file mmap if vma close is implemented.
  FW_LOADER: fix kconfig dependency warning on HOTPLUG
  uio: Statically allocate uio_class and use class .dev_attrs.
  uio: Support 2^MINOR_BITS minors
  uio: Cleanup irq handling.
  uio: Don't clear driver data
  uio: Fix lack of locking in init_uio_class
  SYSFS: Allow boot time switching between deprecated and modern sysfs layout
  driver core: remove CONFIG_SYSFS_DEPRECATED_V2 but keep it for block devices
  ...

34 files changed, 1238 insertions, 516 deletions

diff --git a/Documentation/ABI/testing/sysfs-module b/Documentation/ABI/testing/sysfs-module
new file mode 100644
index 00000000000..cfcec3bffc0
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-module
@@ -0,0 +1,12 @@
+What:		/sys/module/pch_phub/drivers/.../pch_mac
+Date:		August 2010
+KernelVersion:	2.6.35
+Contact:	masa-korg@dsn.okisemi.com
+Description:	Write/read GbE MAC address.
+
+What:		/sys/module/pch_phub/drivers/.../pch_firmware
+Date:		August 2010
+KernelVersion:	2.6.35
+Contact:	masa-korg@dsn.okisemi.com
+Description:	Write/read Option ROM data.
+
diff --git a/Documentation/dynamic-debug-howto.txt b/Documentation/dynamic-debug-howto.txt
index 674c5663d34..58ea64a9616 100644
--- a/Documentation/dynamic-debug-howto.txt
+++ b/Documentation/dynamic-debug-howto.txt
@@ -24,7 +24,7 @@ Dynamic debug has even more useful features:
    read to display the complete list of known debug statements, to help guide you
 
 Controlling dynamic debug Behaviour
-===============================
+===================================
 
 The behaviour of pr_debug()/dev_debug()s are controlled via writing to a
 control file in the 'debugfs' filesystem. Thus, you must first mount the debugfs
@@ -212,6 +212,26 @@ Note the regexp ^[-+=][scp]+$ matches a flags specification.
 Note also that there is no convenient syntax to remove all
 the flags at once, you need to use "-psc".
 
+
+Debug messages during boot process
+==================================
+
+To be able to activate debug messages during the boot process,
+even before userspace and debugfs exists, use the boot parameter:
+ddebug_query="QUERY"
+
+QUERY follows the syntax described above, but must not exceed 1023
+characters. The enablement of debug messages is done as an arch_initcall.
+Thus you can enable debug messages in all code processed after this
+arch_initcall via this boot parameter.
+On an x86 system for example ACPI enablement is a subsys_initcall and
+ddebug_query="file ec.c +p"
+will show early Embedded Controller transactions during ACPI setup if
+your machine (typically a laptop) has an Embedded Controller.
+PCI (or other devices) initialization also is a hot candidate for using
+this boot parameter for debugging purposes.
+
+
 Examples
 ========
 
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 02f21d9220c..4cd8b86e00e 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -43,10 +43,11 @@ parameter is applicable:
 	AVR32	AVR32 architecture is enabled.
 	AX25	Appropriate AX.25 support is enabled.
 	BLACKFIN Blackfin architecture is enabled.
-	DRM	Direct Rendering Management support is enabled.
 	EDD	BIOS Enhanced Disk Drive Services (EDD) is enabled
 	EFI	EFI Partitioning (GPT) is enabled
 	EIDE	EIDE/ATAPI support is enabled.
+	DRM	Direct Rendering Management support is enabled.
+	DYNAMIC_DEBUG Build in debug messages and enable them at runtime
 	FB	The frame buffer device is enabled.
 	GCOV	GCOV profiling is enabled.
 	HW	Appropriate hardware is enabled.
@@ -570,6 +571,10 @@ and is between 256 and 4096 characters. It is defined in the file
 			Format: <port#>,<type>
 			See also Documentation/input/joystick-parport.txt
 
+	ddebug_query=   [KNL,DYNAMIC_DEBUG] Enable debug messages at early boot
+			time. See Documentation/dynamic-debug-howto.txt for
+			details.
+
 	debug		[KNL] Enable kernel debugging (events log level).
 
 	debug_locks_verbose=
@@ -2370,6 +2375,15 @@ and is between 256 and 4096 characters. It is defined in the file
 
 	switches=	[HW,M68k]
 
+	sysfs.deprecated=0|1 [KNL]
+			Enable/disable old style sysfs layout for old udev
+			on older distributions. When this option is enabled
+			very new udev will not work anymore. When this option
+			is disabled (or CONFIG_SYSFS_DEPRECATED not compiled)
+			in older udev will not work anymore.
+			Default depends on CONFIG_SYSFS_DEPRECATED_V2 set in
+			the kernel configuration.
+
 	sysrq_always_enabled
 			[KNL]
 			Ignore sysrq setting - this boot parameter will
diff --git a/MAINTAINERS b/MAINTAINERS
index b618b1e86c4..fd19b544a1b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2064,14 +2064,16 @@ F:	drivers/block/drbd/
 F:	lib/lru_cache.c
 F:	Documentation/blockdev/drbd/
 
-DRIVER CORE, KOBJECTS, AND SYSFS
+DRIVER CORE, KOBJECTS, DEBUGFS AND SYSFS
 M:	Greg Kroah-Hartman <gregkh@suse.de>
 T:	quilt kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/
 S:	Supported
 F:	Documentation/kobject.txt
 F:	drivers/base/
 F:	fs/sysfs/
+F:	fs/debugfs/
 F:	include/linux/kobj*
+F:	include/linux/debugfs.h
 F:	lib/kobj*
 
 DRM DRIVERS
diff --git a/block/genhd.c b/block/genhd.c
index 8313834596d..a8adf96a4b4 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -22,9 +22,7 @@
 #include "blk.h"
 
 static DEFINE_MUTEX(block_class_lock);
-#ifndef CONFIG_SYSFS_DEPRECATED
 struct kobject *block_depr;
-#endif
 
 /* for extended dynamic devt allocation, currently only one major is used */
 #define MAX_EXT_DEVT		(1 << MINORBITS)
@@ -810,10 +808,9 @@ static int __init genhd_device_init(void)
 
 	register_blkdev(BLOCK_EXT_MAJOR, "blkext");
 
-#ifndef CONFIG_SYSFS_DEPRECATED
 	/* create top-level block dir */
-	block_depr = kobject_create_and_add("block", NULL);
-#endif
+	if (!sysfs_deprecated)
+		block_depr = kobject_create_and_add("block", NULL);
 	return 0;
 }
 
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index ef38aff737e..fd96345bc35 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -71,7 +71,6 @@ config PREVENT_FIRMWARE_BUILD
 
 config FW_LOADER
 	tristate "Userspace firmware loading support" if EMBEDDED
-	depends on HOTPLUG
 	default y
 	---help---
 	  This option is provided for the case where no in-kernel-tree modules
diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index c12c7f2f2a6..5f51c3b4451 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -19,7 +19,5 @@ obj-$(CONFIG_MODULES)	+= module.o
 endif
 obj-$(CONFIG_SYS_HYPERVISOR) += hypervisor.o
 
-ifeq ($(CONFIG_DEBUG_DRIVER),y)
-EXTRA_CFLAGS += -DDEBUG
-endif
+ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG
 
diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index eb1b7fa20dc..33c270a64db 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -440,22 +440,6 @@ static void device_remove_attrs(struct bus_type *bus, struct device *dev)
 	}
 }
 
-#ifdef CONFIG_SYSFS_DEPRECATED
-static int make_deprecated_bus_links(struct device *dev)
-{
-	return sysfs_create_link(&dev->kobj,
-				 &dev->bus->p->subsys.kobj, "bus");
-}
-
-static void remove_deprecated_bus_links(struct device *dev)
-{
-	sysfs_remove_link(&dev->kobj, "bus");
-}
-#else
-static inline int make_deprecated_bus_links(struct device *dev) { return 0; }
-static inline void remove_deprecated_bus_links(struct device *dev) { }
-#endif
-
 /**
  * bus_add_device - add device to bus
  * @dev: device being added
@@ -482,15 +466,10 @@ int bus_add_device(struct device *dev)
 				&dev->bus->p->subsys.kobj, "subsystem");
 		if (error)
 			goto out_subsys;
-		error = make_deprecated_bus_links(dev);
-		if (error)
-			goto out_deprecated;
 		klist_add_tail(&dev->p->knode_bus, &bus->p->klist_devices);
 	}
 	return 0;
 
-out_deprecated:
-	sysfs_remove_link(&dev->kobj, "subsystem");
 out_subsys:
 	sysfs_remove_link(&bus->p->devices_kset->kobj, dev_name(dev));
 out_id:
@@ -530,7 +509,6 @@ void bus_remove_device(struct device *dev)
 {
 	if (dev->bus) {
 		sysfs_remove_link(&dev->kobj, "subsystem");
-		remove_deprecated_bus_links(dev);
 		sysfs_remove_link(&dev->bus->p->devices_kset->kobj,
 				  dev_name(dev));
 		device_remove_attrs(dev->bus, dev);
diff --git a/drivers/base/class.c b/drivers/base/class.c
index 8e231d05b40..9c63a5687d6 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -184,9 +184,9 @@ int __class_register(struct class *cls, struct lock_class_key *key)
 	if (!cls->dev_kobj)
 		cls->dev_kobj = sysfs_dev_char_kobj;
 
-#if defined(CONFIG_SYSFS_DEPRECATED) && defined(CONFIG_BLOCK)
+#if defined(CONFIG_BLOCK)
 	/* let the block class directory show up in the root of sysfs */
-	if (cls != &block_class)
+	if (!sysfs_deprecated || cls != &block_class)
 		cp->class_subsys.kobj.kset = class_kset;
 #else
 	cp->class_subsys.kobj.kset = class_kset;
@@ -276,25 +276,6 @@ void class_destroy(struct class *cls)
 	class_unregister(cls);
 }
 
-#ifdef CONFIG_SYSFS_DEPRECATED
-char *make_class_name(const char *name, struct kobject *kobj)
-{
-	char *class_name;
-	int size;
-
-	size = strlen(name) + strlen(kobject_name(kobj)) + 2;
-
-	class_name = kmalloc(size, GFP_KERNEL);
-	if (!class_name)
-		return NULL;
-
-	strcpy(class_name, name);
-	strcat(class_name, ":");
-	strcat(class_name, kobject_name(kobj));
-	return class_name;
-}
-#endif
-
 /**
  * class_dev_iter_init - initialize class device iterator
  * @iter: class iterator to initialize
diff --git a/drivers/base/core.c b/drivers/base/core.c
index d1b2c9adc27..2cb49a93b1e 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -26,6 +26,19 @@
 #include "base.h"
 #include "power/power.h"
 
+#ifdef CONFIG_SYSFS_DEPRECATED
+#ifdef CONFIG_SYSFS_DEPRECATED_V2
+long sysfs_deprecated = 1;
+#else
+long sysfs_deprecated = 0;
+#endif
+static __init int sysfs_deprecated_setup(char *arg)
+{
+	return strict_strtol(arg, 10, &sysfs_deprecated);
+}
+early_param("sysfs.deprecated", sysfs_deprecated_setup);
+#endif
+
 int (*platform_notify)(struct device *dev) = NULL;
 int (*platform_notify_remove)(struct device *dev) = NULL;
 static struct kobject *dev_kobj;
@@ -203,37 +216,6 @@ static int dev_uevent(struct kset *kset, struct kobject *kobj,
 	if (dev->driver)
 		add_uevent_var(env, "DRIVER=%s", dev->driver->name);
 
-#ifdef CONFIG_SYSFS_DEPRECATED
-	if (dev->class) {
-		struct device *parent = dev->parent;
-
-		/* find first bus device in parent chain */
-		while (parent && !parent->bus)
-			parent = parent->parent;
-		if (parent && parent->bus) {
-			const char *path;
-
-			path = kobject_get_path(&parent->kobj, GFP_KERNEL);
-			if (path) {
-				add_uevent_var(env, "PHYSDEVPATH=%s", path);
-				kfree(path);
-			}
-
-			add_uevent_var(env, "PHYSDEVBUS=%s", parent->bus->name);
-
-			if (parent->driver)
-				add_uevent_var(env, "PHYSDEVDRIVER=%s",
-					       parent->driver->name);
-		}
-	} else if (dev->bus) {
-		add_uevent_var(env, "PHYSDEVBUS=%s", dev->bus->name);
-
-		if (dev->driver)
-			add_uevent_var(env, "PHYSDEVDRIVER=%s",
-				       dev->driver->name);
-	}
-#endif
-
 	/* have the bus specific function add its stuff */
 	if (dev->bus && dev->bus->uevent) {
 		retval = dev->bus->uevent(dev, env);
@@ -578,24 +560,6 @@ void device_initialize(struct device *dev)
 	set_dev_node(dev, -1);
 }
 
-#ifdef CONFIG_SYSFS_DEPRECATED
-static struct kobject *get_device_parent(struct device *dev,
-					 struct device *parent)
-{
-	/* class devices without a parent live in /sys/class/<classname>/ */
-	if (dev->class && (!parent || parent->class != dev->class))
-		return &dev->class->p->class_subsys.kobj;
-	/* all other devices keep their parent */
-	else if (parent)
-		return &parent->kobj;
-
-	return NULL;
-}
-
-static inline void cleanup_device_parent(struct device *dev) {}
-static inline void cleanup_glue_dir(struct device *dev,
-				    struct kobject *glue_dir) {}
-#else
 static struct kobject *virtual_device_parent(struct device *dev)
 {
 	static struct kobject *virtual_dir = NULL;
@@ -666,6 +630,15 @@ static struct kobject *get_device_parent(struct device *dev,
 		struct kobject *parent_kobj;
 		struct kobject *k;
 
+#ifdef CONFIG_BLOCK
+		/* block disks show up in /sys/block */
+		if (sysfs_deprecated && dev->class == &block_class) {
+			if (parent && parent->class == &block_class)
+				return &parent->kobj;
+			return &block_class.p->class_subsys.kobj;
+		}
+#endif
+
 		/*
 		 * If we have no parent, we live in "virtual".
 		 * Class-devices with a non class-device as parent, live
@@ -719,7 +692,6 @@ static void cleanup_device_parent(struct device *dev)
 {
 	cleanup_glue_dir(dev, dev->kobj.parent);
 }
-#endif
 
 static void setup_parent(struct device *dev, struct device *parent)
 {
@@ -742,70 +714,29 @@ static int device_add_class_symlinks(struct device *dev)
 	if (error)
 		goto out;
 
-#ifdef CONFIG_SYSFS_DEPRECATED
-	/* stacked class devices need a symlink in the class directory */
-	if (dev->kobj.parent != &dev->class->p->class_subsys.kobj &&
-	    device_is_not_partition(dev)) {
-		error = sysfs_create_link(&dev->class->p->class_subsys.kobj,
-					  &dev->kobj, dev_name(dev));
-		if (error)
-			goto out_subsys;
-	}
-
 	if (dev->parent && device_is_not_partition(dev)) {
-		struct device *parent = dev->parent;
-		char *class_name;
-
-		/*
-		 * stacked class devices have the 'device' link
-		 * pointing to the bus device instead of the parent
-		 */
-		while (parent->class && !parent->bus && parent->parent)
-			parent = parent->parent;
-
-		error = sysfs_create_link(&dev->kobj,
-					  &parent->kobj,
+		error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
 					  "device");
 		if (error)
-			goto out_busid;
-
-		class_name = make_class_name(dev->class->name,
-						&dev->kobj);
-		if (class_name)
-			error = sysfs_create_link(&dev->parent->kobj,
-						&dev->kobj, class_name);
-		kfree(class_name);
-		if (error)
-			goto out_device;
+			goto out_subsys;
 	}
-	return 0;
 
-out_device:
-	if (dev->parent && device_is_not_partition(dev))
-		sysfs_remove_link(&dev->kobj, "device");
-out_busid:
-	if (dev->kobj.parent != &dev->class->p->class_subsys.kobj &&
-	    device_is_not_partition(dev))
-		sysfs_delete_link(&dev->class->p->class_subsys.kobj, &dev->kobj,
-				  dev_name(dev));
-#else
+#ifdef CONFIG_BLOCK
+	/* /sys/block has directories and does not need symlinks */
+	if (sysfs_deprecated && dev->class == &block_class)
+		return 0;
+#endif
+
 	/* link in the class directory pointing to the device */
 	error = sysfs_create_link(&dev->class->p->class_subsys.kobj,
 				  &dev->kobj, dev_name(dev));
 	if (error)
-		goto out_subsys;
+		goto out_device;
 
-	if (dev->parent && device_is_not_partition(dev)) {
-		error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
-					  "device");
-		if (error)
-			goto out_busid;
-	}
 	return 0;
 
-out_busid:
-	sysfs_delete_link(&dev->class->p->class_subsys.kobj, &dev->kobj, dev_name(dev));
-#endif
+out_device:
+	sysfs_remove_link(&dev->kobj, "device");
 
 out_subsys:
 	sysfs_remove_link(&dev->kobj, "subsystem");
@@ -818,30 +749,14 @@ static void device_remove_class_symlinks(struct device *dev)
 	if (!dev->class)
 		return;
 
-#ifdef CONFIG_SYSFS_DEPRECATED
-	if (dev->parent && device_is_not_partition(dev)) {
-		char *class_name;
-
-		class_name = make_class_name(dev->class->name, &dev->kobj);
-		if (class_name) {
-			sysfs_remove_link(&dev->parent->kobj, class_name);
-			kfree(class_name);
-		}
-		sysfs_remove_link(&dev->kobj, "device");
-	}
-
-	if (dev->kobj.parent != &dev->class->p->class_subsys.kobj &&
-	    device_is_not_partition(dev))
-		sysfs_delete_link(&dev->class->p->class_subsys.kobj, &dev->kobj,
-				  dev_name(dev));
-#else
 	if (dev->parent && device_is_not_partition(dev))
 		sysfs_remove_link(&dev->kobj, "device");
-
-	sysfs_delete_link(&dev->class->p->class_subsys.kobj, &dev->kobj, dev_name(dev));
-#endif
-
 	sysfs_remove_link(&dev->kobj, "subsystem");
+#ifdef CONFIG_BLOCK
+	if (sysfs_deprecated && dev->class == &block_class)
+		return;
+#endif
+	sysfs_delete_link(&dev->class->p->class_subsys.kobj, &dev->kobj, dev_name(dev));
 }
 
 /**
@@ -1613,41 +1528,23 @@ int device_rename(struct device *dev, const char *new_name)
 	pr_debug("device: '%s': %s: renaming to '%s'\n", dev_name(dev),
 		 __func__, new_name);
 
-#ifdef CONFIG_SYSFS_DEPRECATED
-	if ((dev->class) && (dev->parent))
-		old_class_name = make_class_name(dev->class->name, &dev->kobj);
-#endif
-
 	old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
 	if (!old_device_name) {
 		error = -ENOMEM;
 		goto out;
 	}
 
-#ifndef CONFIG_SYSFS_DEPRECATED
 	if (dev->class) {
 		error = sysfs_rename_link(&dev->class->p->class_subsys.kobj,
 			&dev->kobj, old_device_name, new_name);
 		if (error)
 			goto out;
 	}
-#endif
+
 	error = kobject_rename(&dev->kobj, new_name);
 	if (error)
 		goto out;
 
-#ifdef CONFIG_SYSFS_DEPRECATED
-	if (old_class_name) {
-		new_class_name = make_class_name(dev->class->name, &dev->kobj);
-		if (new_class_name) {
-			error = sysfs_rename_link(&dev->parent->kobj,
-						  &dev->kobj,
-						  old_class_name,
-						  new_class_name);
-		}
-	}
-#endif
-
 out:
 	put_device(dev);
 
@@ -1664,40 +1561,13 @@ static int device_move_class_links(struct device *dev,
 				   struct device *new_parent)
 {
 	int error = 0;
-#ifdef CONFIG_SYSFS_DEPRECATED
-	char *class_name;
 
-	class_name = make_class_name(dev->class->name, &dev->kobj);
-	if (!class_name) {
-		error = -ENOMEM;
-		goto out;
-	}
-	if (old_parent) {
-		sysfs_remove_link(&dev->kobj, "device");
-		sysfs_remove_link(&old_parent->kobj, class_name);
-	}
-	if (new_parent) {
-		error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
-					  "device");
-		if (error)
-			goto out;
-		error = sysfs_create_link(&new_parent->kobj, &dev->kobj,
-					  class_name);
-		if (error)
-			sysfs_remove_link(&dev->kobj, "device");
-	} else
-		error = 0;
-out:
-	kfree(class_name);
-	return error;
-#else
 	if (old_parent)
 		sysfs_remove_link(&dev->kobj, "device");
 	if (new_parent)
 		error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
 					  "device");
 	return error;
-#endif
 }
 
 /**
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 933442f4032..cafeaaf0428 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -27,6 +27,8 @@
 #include <asm/atomic.h>
 #include <asm/uaccess.h>
 
+static DEFINE_MUTEX(mem_sysfs_mutex);
+
 #define MEMORY_CLASS_NAME	"memory"
 
 static struct sysdev_class memory_sysdev_class = {
@@ -435,6 +437,45 @@ int __weak arch_get_memory_phys_device(unsigned long start_pfn)
 	return 0;
 }
 
+struct memory_block *find_memory_block_hinted(struct mem_section *section,
+					      struct memory_block *hint)
+{
+	struct kobject *kobj;
+	struct sys_device *sysdev;
+	struct memory_block *mem;
+	char name[sizeof(MEMORY_CLASS_NAME) + 9 + 1];
+
+	kobj = hint ? &hint->sysdev.kobj : NULL;
+
+	/*
+	 * This only works because we know that section == sysdev->id
+	 * slightly redundant with sysdev_register()
+	 */
+	sprintf(&name[0], "%s%d", MEMORY_CLASS_NAME, __section_nr(section));
+
+	kobj = kset_find_obj_hinted(&memory_sysdev_class.kset, name, kobj);
+	if (!kobj)
+		return NULL;
+
+	sysdev = container_of(kobj, struct sys_device, kobj);
+	mem = container_of(sysdev, struct memory_block, sysdev);
+
+	return mem;
+}
+
+/*
+ * For now, we have a linear search to go find the appropriate
+ * memory_block corresponding to a particular phys_index. If
+ * this gets to be a real problem, we can always use a radix
+ * tree or something here.
+ *
+ * This could be made generic for all sysdev classes.
+ */
+struct memory_block *find_memory_block(struct mem_section *section)
+{
+	return find_memory_block_hinted(section, NULL);
+}
+
 static int add_memory_block(int nid, struct mem_section *section,
 			unsigned long state, enum mem_add_context context)
 {
@@ -445,8 +486,11 @@ static int add_memory_block(int nid, struct mem_section *section,
 	if (!mem)
 		return -ENOMEM;
 
+	mutex_lock(&mem_sysfs_mutex);
+
 	mem->phys_index = __section_nr(section);
 	mem->state = state;
+	mem->section_count++;
 	mutex_init(&mem->state_mutex);
 	start_pfn = section_nr_to_pfn(mem->phys_index);
 	mem->phys_device = arch_get_memory_phys_device(start_pfn);
@@ -465,53 +509,29 @@ static int add_memory_block(int nid, struct mem_section *section,
 			ret = register_mem_sect_under_node(mem, nid);
 	}
 
+	mutex_unlock(&mem_sysfs_mutex);
 	return ret;
 }
 
-/*
- * For now, we have a linear search to go find the appropriate
- * memory_block corresponding to a particular phys_index. If
- * this gets to be a real problem, we can always use a radix
- * tree or something here.
- *
- * This could be made generic for all sysdev classes.
- */
-struct memory_block *find_memory_block(struct mem_section *section)
-{
-	struct kobject *kobj;
-	struct sys_device *sysdev;
-	struct memory_block *mem;
-	char name[sizeof(MEMORY_CLASS_NAME) + 9 + 1];
-
-	/*
-	 * This only works because we know that section == sysdev->id
-	 * slightly redundant with sysdev_register()
-	 */
-	sprintf(&name[0], "%s%d", MEMORY_CLASS_NAME, __section_nr(section));
-
-	kobj = kset_find_obj(&memory_sysdev_class.kset, name);
-	if (!kobj)
-		return NULL;
-
-	sysdev = container_of(kobj, struct sys_device, kobj);
-	mem = container_of(sysdev, struct memory_block, sysdev);
-
-	return mem;
-}
-
 int remove_memory_block(unsigned long node_id, struct mem_section *section,
 		int phys_device)
 {
 	struct memory_block *mem;
 
+	mutex_lock(&mem_sysfs_mutex);
 	mem = find_memory_block(section);
-	unregister_mem_sect_under_nodes(mem);
-	mem_remove_simple_file(mem, phys_index);
-	mem_remove_simple_file(mem, state);
-	mem_remove_simple_file(mem, phys_device);
-	mem_remove_simple_file(mem, removable);
-	unregister_memory(mem, section);
 
+	mem->section_count--;
+	if (mem->section_count == 0) {
+		unregister_mem_sect_under_nodes(mem);
+		mem_remove_simple_file(mem, phys_index);
+		mem_remove_simple_file(mem, state);
+		mem_remove_simple_file(mem, phys_device);
+		mem_remove_simple_file(mem, removable);
+		unregister_memory(mem, section);
+	}
+
+	mutex_unlock(&mem_sysfs_mutex);
 	return 0;
 }
 
diff --git a/drivers/base/node.c b/drivers/base/node.c
index 2872e86837b..ee53558b452 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -409,25 +409,27 @@ static int link_mem_sections(int nid)
 	unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
 	unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
 	unsigned long pfn;
+	struct memory_block *mem_blk = NULL;
 	int err = 0;
 
 	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
 		unsigned long section_nr = pfn_to_section_nr(pfn);
 		struct mem_section *mem_sect;
-		struct memory_block *mem_blk;
 		int ret;
 
 		if (!present_section_nr(section_nr))
 			continue;
 		mem_sect = __nr_to_section(section_nr);
-		mem_blk = find_memory_block(mem_sect);
+		mem_blk = find_memory_block_hinted(mem_sect, mem_blk);
 		ret = register_mem_sect_under_node(mem_blk, nid);
 		if (!err)
 			err = ret;
 
 		/* discard ref obtained in find_memory_block() */
-		kobject_put(&mem_blk->sysdev.kobj);
 	}
+
+	if (mem_blk)
+		kobject_put(&mem_blk->sysdev.kobj);
 	return err;
 }
 
diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index c6c933f5810..3966e62ad01 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -192,6 +192,9 @@ int platform_device_add_resources(struct platform_device *pdev,
 {
 	struct resource *r;
 
+	if (!res)
+		return 0;
+
 	r = kmemdup(res, sizeof(struct resource) * num, GFP_KERNEL);
 	if (r) {
 		pdev->resource = r;
@@ -215,8 +218,12 @@ EXPORT_SYMBOL_GPL(platform_device_add_resources);
 int platform_device_add_data(struct platform_device *pdev, const void *data,
 			     size_t size)
 {
-	void *d = kmemdup(data, size, GFP_KERNEL);
+	void *d;
+
+	if (!data)
+		return 0;
 
+	d = kmemdup(data, size, GFP_KERNEL);
 	if (d) {
 		pdev->dev.platform_data = d;
 		return 0;
@@ -373,17 +380,13 @@ struct platform_device *__init_or_module platform_device_register_resndata(
 
 	pdev->dev.parent = parent;
 
-	if (res) {
-		ret = platform_device_add_resources(pdev, res, num);
-		if (ret)
-			goto err;
-	}
+	ret = platform_device_add_resources(pdev, res, num);
+	if (ret)
+		goto err;
 
-	if (data) {
-		ret = platform_device_add_data(pdev, data, size);
-		if (ret)
-			goto err;
-	}