core.c 28.7 KB
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/*
 * drivers/base/core.c - core driver model code (device registration, etc)
 *
 * Copyright (c) 2002-3 Patrick Mochel
 * Copyright (c) 2002-3 Open Source Development Labs
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 * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
 * Copyright (c) 2006 Novell, Inc.
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 *
 * This file is released under the GPLv2
 *
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/string.h>
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#include <linux/kdev_t.h>
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#include <linux/notifier.h>
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#include <asm/semaphore.h>

#include "base.h"
#include "power/power.h"

int (*platform_notify)(struct device * dev) = NULL;
int (*platform_notify_remove)(struct device * dev) = NULL;

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/*
 * Detect the LANANA-assigned LOCAL/EXPERIMENTAL majors
 */
bool is_lanana_major(unsigned int major)
{
	if (major >= 60 && major <= 63)
		return 1;
	if (major >= 120 && major <= 127)
		return 1;
	if (major >= 240 && major <= 254)
		return 1;
	return 0;
}

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/*
 * sysfs bindings for devices.
 */

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/**
 * dev_driver_string - Return a device's driver name, if at all possible
 * @dev: struct device to get the name of
 *
 * Will return the device's driver's name if it is bound to a device.  If
 * the device is not bound to a device, it will return the name of the bus
 * it is attached to.  If it is not attached to a bus either, an empty
 * string will be returned.
 */
const char *dev_driver_string(struct device *dev)
{
	return dev->driver ? dev->driver->name :
			(dev->bus ? dev->bus->name : "");
}
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EXPORT_SYMBOL(dev_driver_string);
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#define to_dev(obj) container_of(obj, struct device, kobj)
#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)

static ssize_t
dev_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
{
	struct device_attribute * dev_attr = to_dev_attr(attr);
	struct device * dev = to_dev(kobj);
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	ssize_t ret = -EIO;
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	if (dev_attr->show)
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		ret = dev_attr->show(dev, dev_attr, buf);
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	return ret;
}

static ssize_t
dev_attr_store(struct kobject * kobj, struct attribute * attr,
	       const char * buf, size_t count)
{
	struct device_attribute * dev_attr = to_dev_attr(attr);
	struct device * dev = to_dev(kobj);
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	ssize_t ret = -EIO;
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	if (dev_attr->store)
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		ret = dev_attr->store(dev, dev_attr, buf, count);
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	return ret;
}

static struct sysfs_ops dev_sysfs_ops = {
	.show	= dev_attr_show,
	.store	= dev_attr_store,
};


/**
 *	device_release - free device structure.
 *	@kobj:	device's kobject.
 *
 *	This is called once the reference count for the object
 *	reaches 0. We forward the call to the device's release
 *	method, which should handle actually freeing the structure.
 */
static void device_release(struct kobject * kobj)
{
	struct device * dev = to_dev(kobj);

	if (dev->release)
		dev->release(dev);
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	else if (dev->type && dev->type->release)
		dev->type->release(dev);
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	else if (dev->class && dev->class->dev_release)
		dev->class->dev_release(dev);
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	else {
		printk(KERN_ERR "Device '%s' does not have a release() function, "
			"it is broken and must be fixed.\n",
			dev->bus_id);
		WARN_ON(1);
	}
}

static struct kobj_type ktype_device = {
	.release	= device_release,
	.sysfs_ops	= &dev_sysfs_ops,
};


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static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
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{
	struct kobj_type *ktype = get_ktype(kobj);

	if (ktype == &ktype_device) {
		struct device *dev = to_dev(kobj);
		if (dev->bus)
			return 1;
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		if (dev->class)
			return 1;
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	}
	return 0;
}

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static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
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{
	struct device *dev = to_dev(kobj);

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	if (dev->bus)
		return dev->bus->name;
	if (dev->class)
		return dev->class->name;
	return NULL;
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}

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static int dev_uevent(struct kset *kset, struct kobject *kobj, char **envp,
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			int num_envp, char *buffer, int buffer_size)
{
	struct device *dev = to_dev(kobj);
	int i = 0;
	int length = 0;
	int retval = 0;

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	/* add the major/minor if present */
	if (MAJOR(dev->devt)) {
		add_uevent_var(envp, num_envp, &i,
			       buffer, buffer_size, &length,
			       "MAJOR=%u", MAJOR(dev->devt));
		add_uevent_var(envp, num_envp, &i,
			       buffer, buffer_size, &length,
			       "MINOR=%u", MINOR(dev->devt));
	}

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	if (dev->driver)
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		add_uevent_var(envp, num_envp, &i,
			       buffer, buffer_size, &length,
			       "DRIVER=%s", dev->driver->name);
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#ifdef CONFIG_SYSFS_DEPRECATED
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	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);
			add_uevent_var(envp, num_envp, &i,
				       buffer, buffer_size, &length,
				       "PHYSDEVPATH=%s", path);
			kfree(path);

			add_uevent_var(envp, num_envp, &i,
				       buffer, buffer_size, &length,
				       "PHYSDEVBUS=%s", parent->bus->name);

			if (parent->driver)
				add_uevent_var(envp, num_envp, &i,
					       buffer, buffer_size, &length,
					       "PHYSDEVDRIVER=%s", parent->driver->name);
		}
	} else if (dev->bus) {
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		add_uevent_var(envp, num_envp, &i,
			       buffer, buffer_size, &length,
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			       "PHYSDEVBUS=%s", dev->bus->name);

		if (dev->driver)
			add_uevent_var(envp, num_envp, &i,
				       buffer, buffer_size, &length,
				       "PHYSDEVDRIVER=%s", dev->driver->name);
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	}
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#endif
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	/* terminate, set to next free slot, shrink available space */
	envp[i] = NULL;
	envp = &envp[i];
	num_envp -= i;
	buffer = &buffer[length];
	buffer_size -= length;

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	if (dev->bus && dev->bus->uevent) {
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		/* have the bus specific function add its stuff */
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		retval = dev->bus->uevent(dev, envp, num_envp, buffer, buffer_size);
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		if (retval)
			pr_debug ("%s: bus uevent() returned %d\n",
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				  __FUNCTION__, retval);
	}

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	if (dev->class && dev->class->dev_uevent) {
		/* have the class specific function add its stuff */
		retval = dev->class->dev_uevent(dev, envp, num_envp, buffer, buffer_size);
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		if (retval)
			pr_debug("%s: class uevent() returned %d\n",
				 __FUNCTION__, retval);
	}

	if (dev->type && dev->type->uevent) {
		/* have the device type specific fuction add its stuff */
		retval = dev->type->uevent(dev, envp, num_envp, buffer, buffer_size);
		if (retval)
			pr_debug("%s: dev_type uevent() returned %d\n",
				 __FUNCTION__, retval);
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	}

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	return retval;
}

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static struct kset_uevent_ops device_uevent_ops = {
	.filter =	dev_uevent_filter,
	.name =		dev_uevent_name,
	.uevent =	dev_uevent,
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};

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static ssize_t store_uevent(struct device *dev, struct device_attribute *attr,
			    const char *buf, size_t count)
{
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	kobject_uevent(&dev->kobj, KOBJ_ADD);
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	return count;
}

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static int device_add_groups(struct device *dev)
{
	int i;
	int error = 0;

	if (dev->groups) {
		for (i = 0; dev->groups[i]; i++) {
			error = sysfs_create_group(&dev->kobj, dev->groups[i]);
			if (error) {
				while (--i >= 0)
					sysfs_remove_group(&dev->kobj, dev->groups[i]);
				goto out;
			}
		}
	}
out:
	return error;
}

static void device_remove_groups(struct device *dev)
{
	int i;
	if (dev->groups) {
		for (i = 0; dev->groups[i]; i++) {
			sysfs_remove_group(&dev->kobj, dev->groups[i]);
		}
	}
}

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static int device_add_attrs(struct device *dev)
{
	struct class *class = dev->class;
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	struct device_type *type = dev->type;
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	int error = 0;
	int i;

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	if (class && class->dev_attrs) {
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		for (i = 0; attr_name(class->dev_attrs[i]); i++) {
			error = device_create_file(dev, &class->dev_attrs[i]);
			if (error)
				break;
		}
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		if (error)
			while (--i >= 0)
				device_remove_file(dev, &class->dev_attrs[i]);
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	}
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	if (type && type->attrs) {
		for (i = 0; attr_name(type->attrs[i]); i++) {
			error = device_create_file(dev, &type->attrs[i]);
			if (error)
				break;
		}
		if (error)
			while (--i >= 0)
				device_remove_file(dev, &type->attrs[i]);
	}

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	return error;
}

static void device_remove_attrs(struct device *dev)
{
	struct class *class = dev->class;
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	struct device_type *type = dev->type;
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	int i;

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	if (class && class->dev_attrs) {
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		for (i = 0; attr_name(class->dev_attrs[i]); i++)
			device_remove_file(dev, &class->dev_attrs[i]);
	}
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	if (type && type->attrs) {
		for (i = 0; attr_name(type->attrs[i]); i++)
			device_remove_file(dev, &type->attrs[i]);
	}
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}


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static ssize_t show_dev(struct device *dev, struct device_attribute *attr,
			char *buf)
{
	return print_dev_t(buf, dev->devt);
}

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/*
 *	devices_subsys - structure to be registered with kobject core.
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 */

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decl_subsys(devices, &ktype_device, &device_uevent_ops);
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/**
 *	device_create_file - create sysfs attribute file for device.
 *	@dev:	device.
 *	@attr:	device attribute descriptor.
 */

int device_create_file(struct device * dev, struct device_attribute * attr)
{
	int error = 0;
	if (get_device(dev)) {
		error = sysfs_create_file(&dev->kobj, &attr->attr);
		put_device(dev);
	}
	return error;
}

/**
 *	device_remove_file - remove sysfs attribute file.
 *	@dev:	device.
 *	@attr:	device attribute descriptor.
 */

void device_remove_file(struct device * dev, struct device_attribute * attr)
{
	if (get_device(dev)) {
		sysfs_remove_file(&dev->kobj, &attr->attr);
		put_device(dev);
	}
}

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/**
 * device_create_bin_file - create sysfs binary attribute file for device.
 * @dev: device.
 * @attr: device binary attribute descriptor.
 */
int device_create_bin_file(struct device *dev, struct bin_attribute *attr)
{
	int error = -EINVAL;
	if (dev)
		error = sysfs_create_bin_file(&dev->kobj, attr);
	return error;
}
EXPORT_SYMBOL_GPL(device_create_bin_file);

/**
 * device_remove_bin_file - remove sysfs binary attribute file
 * @dev: device.
 * @attr: device binary attribute descriptor.
 */
void device_remove_bin_file(struct device *dev, struct bin_attribute *attr)
{
	if (dev)
		sysfs_remove_bin_file(&dev->kobj, attr);
}
EXPORT_SYMBOL_GPL(device_remove_bin_file);

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static void klist_children_get(struct klist_node *n)
{
	struct device *dev = container_of(n, struct device, knode_parent);

	get_device(dev);
}

static void klist_children_put(struct klist_node *n)
{
	struct device *dev = container_of(n, struct device, knode_parent);

	put_device(dev);
}

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/**
 *	device_initialize - init device structure.
 *	@dev:	device.
 *
 *	This prepares the device for use by other layers,
 *	including adding it to the device hierarchy.
 *	It is the first half of device_register(), if called by
 *	that, though it can also be called separately, so one
 *	may use @dev's fields (e.g. the refcount).
 */

void device_initialize(struct device *dev)
{
	kobj_set_kset_s(dev, devices_subsys);
	kobject_init(&dev->kobj);
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	klist_init(&dev->klist_children, klist_children_get,
		   klist_children_put);
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	INIT_LIST_HEAD(&dev->dma_pools);
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	INIT_LIST_HEAD(&dev->node);
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	init_MUTEX(&dev->sem);
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	spin_lock_init(&dev->devres_lock);
	INIT_LIST_HEAD(&dev->devres_head);
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	device_init_wakeup(dev, 0);
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	set_dev_node(dev, -1);
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}

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#ifdef CONFIG_SYSFS_DEPRECATED
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static struct kobject * get_device_parent(struct device *dev,
					  struct device *parent)
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{
	/* Set the parent to the class, not the parent device */
	/* this keeps sysfs from having a symlink to make old udevs happy */
	if (dev->class)
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		return &dev->class->subsys.kset.kobj;
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	else if (parent)
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		return &parent->kobj;
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	return NULL;
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}
#else
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static struct kobject * virtual_device_parent(struct device *dev)
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{
	if (!dev->class)
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		return ERR_PTR(-ENODEV);
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	if (!dev->class->virtual_dir) {
		static struct kobject *virtual_dir = NULL;

		if (!virtual_dir)
			virtual_dir = kobject_add_dir(&devices_subsys.kset.kobj, "virtual");
		dev->class->virtual_dir = kobject_add_dir(virtual_dir, dev->class->name);
	}

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	return dev->class->virtual_dir;
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}

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static struct kobject * get_device_parent(struct device *dev,
					  struct device *parent)
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{
	/* if this is a class device, and has no parent, create one */
	if ((dev->class) && (parent == NULL)) {
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		return virtual_device_parent(dev);
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	} else if (parent)
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		return &parent->kobj;
	return NULL;
}
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#endif
static int setup_parent(struct device *dev, struct device *parent)
{
	struct kobject *kobj;
	kobj = get_device_parent(dev, parent);
	if (IS_ERR(kobj))
		return PTR_ERR(kobj);
	if (kobj)
		dev->kobj.parent = kobj;
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	return 0;
}

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/**
 *	device_add - add device to device hierarchy.
 *	@dev:	device.
 *
 *	This is part 2 of device_register(), though may be called
 *	separately _iff_ device_initialize() has been called separately.
 *
 *	This adds it to the kobject hierarchy via kobject_add(), adds it
 *	to the global and sibling lists for the device, then
 *	adds it to the other relevant subsystems of the driver model.
 */
int device_add(struct device *dev)
{
	struct device *parent = NULL;
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	char *class_name = NULL;
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	struct class_interface *class_intf;
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	int error = -EINVAL;

	dev = get_device(dev);
	if (!dev || !strlen(dev->bus_id))
		goto Error;

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	pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id);
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	parent = get_device(dev->parent);

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	error = setup_parent(dev, parent);
	if (error)
		goto Error;
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	/* first, register with generic layer. */
	kobject_set_name(&dev->kobj, "%s", dev->bus_id);
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	error = kobject_add(&dev->kobj);
	if (error)
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		goto Error;
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	/* notify platform of device entry */
	if (platform_notify)
		platform_notify(dev);

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	/* notify clients of device entry (new way) */
	if (dev->bus)
		blocking_notifier_call_chain(&dev->bus->bus_notifier,
					     BUS_NOTIFY_ADD_DEVICE, dev);

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	dev->uevent_attr.attr.name = "uevent";
	dev->uevent_attr.attr.mode = S_IWUSR;
	if (dev->driver)
		dev->uevent_attr.attr.owner = dev->driver->owner;
	dev->uevent_attr.store = store_uevent;
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	error = device_create_file(dev, &dev->uevent_attr);
	if (error)
		goto attrError;
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	if (MAJOR(dev->devt)) {
		struct device_attribute *attr;
		attr = kzalloc(sizeof(*attr), GFP_KERNEL);
		if (!attr) {
			error = -ENOMEM;
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			goto ueventattrError;
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		}
		attr->attr.name = "dev";
		attr->attr.mode = S_IRUGO;
		if (dev->driver)
			attr->attr.owner = dev->driver->owner;
		attr->show = show_dev;
		error = device_create_file(dev, attr);
		if (error) {
			kfree(attr);
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			goto ueventattrError;
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		}

		dev->devt_attr = attr;
	}

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	if (dev->class) {
		sysfs_create_link(&dev->kobj, &dev->class->subsys.kset.kobj,
				  "subsystem");
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		/* If this is not a "fake" compatible device, then create the
		 * symlink from the class to the device. */
		if (dev->kobj.parent != &dev->class->subsys.kset.kobj)
			sysfs_create_link(&dev->class->subsys.kset.kobj,
					  &dev->kobj, dev->bus_id);
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#ifdef CONFIG_SYSFS_DEPRECATED
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		if (parent) {
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			sysfs_create_link(&dev->kobj, &dev->parent->kobj,
							"device");
			class_name = make_class_name(dev->class->name,
							&dev->kobj);
			if (class_name)
				sysfs_create_link(&dev->parent->kobj,
						  &dev->kobj, class_name);
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		}
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#endif
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	}
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	if ((error = device_add_attrs(dev)))
		goto AttrsError;
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	if ((error = device_add_groups(dev)))
		goto GroupError;
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	if ((error = device_pm_add(dev)))
		goto PMError;
	if ((error = bus_add_device(dev)))
		goto BusError;
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	if (!dev->uevent_suppress)
		kobject_uevent(&dev->kobj, KOBJ_ADD);
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	if ((error = bus_attach_device(dev)))
		goto AttachError;
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	if (parent)
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		klist_add_tail(&dev->knode_parent, &parent->klist_children);
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	if (dev->class) {
		down(&dev->class->sem);
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		/* tie the class to the device */
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		list_add_tail(&dev->node, &dev->class->devices);
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		/* notify any interfaces that the device is here */
		list_for_each_entry(class_intf, &dev->class->interfaces, node)
			if (class_intf->add_dev)
				class_intf->add_dev(dev, class_intf);
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		up(&dev->class->sem);
	}
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 Done:
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 	kfree(class_name);
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	put_device(dev);
	return error;
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 AttachError:
	bus_remove_device(dev);
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 BusError:
	device_pm_remove(dev);
 PMError:
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	if (dev->bus)
		blocking_notifier_call_chain(&dev->bus->bus_notifier,
					     BUS_NOTIFY_DEL_DEVICE, dev);
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	device_remove_groups(dev);
 GroupError:
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	device_remove_attrs(dev);
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 AttrsError:
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	if (dev->devt_attr) {
		device_remove_file(dev, dev->devt_attr);
		kfree(dev->devt_attr);
	}
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	if (dev->class) {
		sysfs_remove_link(&dev->kobj, "subsystem");
		/* If this is not a "fake" compatible device, remove the
		 * symlink from the class to the device. */
		if (dev->kobj.parent != &dev->class->subsys.kset.kobj)
			sysfs_remove_link(&dev->class->subsys.kset.kobj,
					  dev->bus_id);
#ifdef CONFIG_SYSFS_DEPRECATED
		if (parent) {
			char *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");
		}
#endif

		down(&dev->class->sem);
		/* notify any interfaces that the device is now gone */
		list_for_each_entry(class_intf, &dev->class->interfaces, node)
			if (class_intf->remove_dev)
				class_intf->remove_dev(dev, class_intf);
		/* remove the device from the class list */
		list_del_init(&dev->node);
		up(&dev->class->sem);
	}
675 676
 ueventattrError:
	device_remove_file(dev, &dev->uevent_attr);
677
 attrError:
678
	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
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	kobject_del(&dev->kobj);
 Error:
	if (parent)
		put_device(parent);
	goto Done;
}


/**
 *	device_register - register a device with the system.
 *	@dev:	pointer to the device structure
 *
 *	This happens in two clean steps - initialize the device
 *	and add it to the system. The two steps can be called
 *	separately, but this is the easiest and most common.
 *	I.e. you should only call the two helpers separately if
 *	have a clearly defined need to use and refcount the device
 *	before it is added to the hierarchy.
 */

int device_register(struct device *dev)
{
	device_initialize(dev);
	return device_add(dev);
}


/**
 *	get_device - increment reference count for device.
 *	@dev:	device.
 *
 *	This simply forwards the call to kobject_get(), though
 *	we do take care to provide for the case that we get a NULL
 *	pointer passed in.
 */

struct device * get_device(struct device * dev)
{
	return dev ? to_dev(kobject_get(&dev->kobj)) : NULL;
}


/**
 *	put_device - decrement reference count.
 *	@dev:	device in question.
 */
void put_device(struct device * dev)
{
	if (dev)
		kobject_put(&dev->kobj);
}


/**
 *	device_del - delete device from system.
 *	@dev:	device.
 *
 *	This is the first part of the device unregistration
 *	sequence. This removes the device from the lists we control
 *	from here, has it removed from the other driver model
 *	subsystems it was added to in device_add(), and removes it
 *	from the kobject hierarchy.
 *
 *	NOTE: this should be called manually _iff_ device_add() was
 *	also called manually.
 */

void device_del(struct device * dev)
{
	struct device * parent = dev->parent;
749
	struct class_interface *class_intf;
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	if (parent)
752
		klist_del(&dev->knode_parent);
753
	if (dev->devt_attr) {
754
		device_remove_file(dev, dev->devt_attr);
755 756
		kfree(dev->devt_attr);
	}
757 758
	if (dev->class) {
		sysfs_remove_link(&dev->kobj, "subsystem");
759 760 761 762 763
		/* If this is not a "fake" compatible device, remove the
		 * symlink from the class to the device. */
		if (dev->kobj.parent != &dev->class->subsys.kset.kobj)
			sysfs_remove_link(&dev->class->subsys.kset.kobj,
					  dev->bus_id);
764
#ifdef CONFIG_SYSFS_DEPRECATED
765
		if (parent) {
766 767
			char *class_name = make_class_name(dev->class->name,
							   &dev->kobj);
768 769 770
			if (class_name)
				sysfs_remove_link(&dev->parent->kobj,
						  class_name);
771 772
			kfree(class_name);
			sysfs_remove_link(&dev->kobj, "device");
773
		}
774 775
#endif

776
		down(&dev->class->sem);
777 778 779 780 781
		/* notify any interfaces that the device is now gone */
		list_for_each_entry(class_intf, &dev->class->interfaces, node)
			if (class_intf->remove_dev)
				class_intf->remove_dev(dev, class_intf);
		/* remove the device from the class list */
782 783
		list_del_init(&dev->node);
		up(&dev->class->sem);
784
	}
785
	device_remove_file(dev, &dev->uevent_attr);
786
	device_remove_groups(dev);
787
	device_remove_attrs(dev);
788
	bus_remove_device(dev);
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	/* Notify the platform of the removal, in case they
	 * need to do anything...
	 */
	if (platform_notify_remove)
		platform_notify_remove(dev);
795 796 797
	if (dev->bus)
		blocking_notifier_call_chain(&dev->bus->bus_notifier,
					     BUS_NOTIFY_DEL_DEVICE, dev);
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	device_pm_remove(dev);
799
	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
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	kobject_del(&dev->kobj);
	if (parent)
		put_device(parent);
}

/**
 *	device_unregister - unregister device from system.
 *	@dev:	device going away.
 *
 *	We do this in two parts, like we do device_register(). First,
 *	we remove it from all the subsystems with device_del(), then
 *	we decrement the reference count via put_device(). If that
 *	is the final reference count, the device will be cleaned up
 *	via device_release() above. Otherwise, the structure will
 *	stick around until the final reference to the device is dropped.
 */
void device_unregister(struct device * dev)
{
	pr_debug("DEV: Unregistering device. ID = '%s'\n", dev->bus_id);
	device_del(dev);
	put_device(dev);
}


824 825 826 827 828 829
static struct device * next_device(struct klist_iter * i)
{
	struct klist_node * n = klist_next(i);
	return n ? container_of(n, struct device, knode_parent) : NULL;
}

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/**
 *	device_for_each_child - device child iterator.
832
 *	@parent: parent struct device.
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 *	@data:	data for the callback.
 *	@fn:	function to be called for each device.
 *
836
 *	Iterate over @parent's child devices, and call @fn for each,
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 *	passing it @data.
 *
 *	We check the return of @fn each time. If it returns anything
 *	other than 0, we break out and return that value.
 */
842
int device_for_each_child(struct device * parent, void * data,
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		     int (*fn)(struct device *, void *))
{
845
	struct klist_iter i;
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	struct device * child;
	int error = 0;

849 850 851 852
	klist_iter_init(&parent->klist_children, &i);
	while ((child = next_device(&i)) && !error)
		error = fn(child, data);
	klist_iter_exit(&i);
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	return error;
}

856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887
/**
 * device_find_child - device iterator for locating a particular device.
 * @parent: parent struct device
 * @data: Data to pass to match function
 * @match: Callback function to check device
 *
 * This is similar to the device_for_each_child() function above, but it
 * returns a reference to a device that is 'found' for later use, as
 * determined by the @match callback.
 *
 * The callback should return 0 if the device doesn't match and non-zero
 * if it does.  If the callback returns non-zero and a reference to the
 * current device can be obtained, this function will return to the caller
 * and not iterate over any more devices.
 */
struct device * device_find_child(struct device *parent, void *data,
				  int (*match)(struct device *, void *))
{
	struct klist_iter i;
	struct device *child;

	if (!parent)
		return NULL;

	klist_iter_init(&parent->klist_children, &i);
	while ((child = next_device(&i)))
		if (match(child, data) && get_device(child))
			break;
	klist_iter_exit(&i);
	return child;
}

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int __init devices_init(void)
{
	return subsystem_register(&devices_subsys);
}

EXPORT_SYMBOL_GPL(device_for_each_child);
894
EXPORT_SYMBOL_GPL(device_find_child);
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EXPORT_SYMBOL_GPL(device_initialize);
EXPORT_SYMBOL_GPL(device_add);
EXPORT_SYMBOL_GPL(device_register);

EXPORT_SYMBOL_GPL(device_del);
EXPORT_SYMBOL_GPL(device_unregister);
EXPORT_SYMBOL_GPL(get_device);
EXPORT_SYMBOL_GPL(put_device);

EXPORT_SYMBOL_GPL(device_create_file);
EXPORT_SYMBOL_GPL(device_remove_file);
907 908 909 910 911 912 913 914 915 916


static void device_create_release(struct device *dev)
{
	pr_debug("%s called for %s\n", __FUNCTION__, dev->bus_id);
	kfree(dev);
}

/**
 * device_create - creates a device and registers it with sysfs
917 918 919 920 921 922 923
 * @class: pointer to the struct class that this device should be registered to
 * @parent: pointer to the parent struct device of this new device, if any
 * @devt: the dev_t for the char device to be added
 * @fmt: string for the device's name
 *
 * This function can be used by char device classes.  A struct device
 * will be created in sysfs, registered to the specified class.
924 925 926
 *
 * A "dev" file will be created, showing the dev_t for the device, if
 * the dev_t is not 0,0.
927 928 929 930
 * If a pointer to a parent struct device is passed in, the newly created
 * struct device will be a child of that device in sysfs.
 * The pointer to the struct device will be returned from the call.
 * Any further sysfs files that might be required can be created using this
931 932 933 934 935 936
 * pointer.
 *
 * Note: the struct class passed to this function must have previously
 * been created with a call to class_create().
 */
struct device *device_create(struct class *class, struct device *parent,
937
			     dev_t devt, const char *fmt, ...)
938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973
{
	va_list args;
	struct device *dev = NULL;
	int retval = -ENODEV;

	if (class == NULL || IS_ERR(class))
		goto error;

	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	if (!dev) {
		retval = -ENOMEM;
		goto error;
	}

	dev->devt = devt;
	dev->class = class;
	dev->parent = parent;
	dev->release = device_create_release;

	va_start(args, fmt);
	vsnprintf(dev->bus_id, BUS_ID_SIZE, fmt, args);
	va_end(args);
	retval = device_register(dev);
	if (retval)
		goto error;

	return dev;

error:
	kfree(dev);
	return ERR_PTR(retval);
}
EXPORT_SYMBOL_GPL(device_create);

/**
 * device_destroy - removes a device that was created with device_create()
974 975
 * @class: pointer to the struct class that this device was registered with
 * @devt: the dev_t of the device that was previously registered
976
 *
977 978
 * This call unregisters and cleans up a device that was created with a
 * call to device_create().
979 980 981 982 983 984 985 986 987 988 989 990 991 992 993
 */
void device_destroy(struct class *class, dev_t devt)
{
	struct device *dev = NULL;
	struct device *dev_tmp;

	down(&class->sem);
	list_for_each_entry(dev_tmp, &class->devices, node) {
		if (dev_tmp->devt == devt) {
			dev = dev_tmp;
			break;
		}
	}
	up(&class->sem);

994
	if (dev)
995 996 997
		device_unregister(dev);
}
EXPORT_SYMBOL_GPL(device_destroy);
998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016

/**
 * device_rename - renames a device
 * @dev: the pointer to the struct device to be renamed
 * @new_name: the new name of the device
 */
int device_rename(struct device *dev, char *new_name)
{
	char *old_class_name = NULL;
	char *new_class_name = NULL;
	char *old_symlink_name = NULL;
	int error;

	dev = get_device(dev);
	if (!dev)
		return -EINVAL;

	pr_debug("DEVICE: renaming '%s' to '%s'\n", dev->bus_id, new_name);

1017
#ifdef CONFIG_SYSFS_DEPRECATED
1018 1019
	if ((dev->class) && (dev->parent))
		old_class_name = make_class_name(dev->class->name, &dev->kobj);
1020
#endif
1021 1022 1023

	if (dev->class) {
		old_symlink_name = kmalloc(BUS_ID_SIZE, GFP_KERNEL);
1024 1025 1026 1027
		if (!old_symlink_name) {
			error = -ENOMEM;
			goto out_free_old_class;
		}
1028 1029 1030 1031 1032 1033 1034
		strlcpy(old_symlink_name, dev->bus_id, BUS_ID_SIZE);
	}

	strlcpy(dev->bus_id, new_name, BUS_ID_SIZE);

	error = kobject_rename(&dev->kobj, new_name);

1035
#ifdef CONFIG_SYSFS_DEPRECATED
1036 1037 1038 1039 1040 1041 1042 1043
	if (old_class_name) {
		new_class_name = make_class_name(dev->class->name, &dev->kobj);
		if (new_class_name) {
			sysfs_create_link(&dev->parent->kobj, &dev->kobj,
					  new_class_name);
			sysfs_remove_link(&dev->parent->kobj, old_class_name);
		}
	}
1044 1045
#endif

1046 1047 1048 1049 1050 1051 1052 1053 1054 1055
	if (dev->class) {
		sysfs_remove_link(&dev->class->subsys.kset.kobj,
				  old_symlink_name);
		sysfs_create_link(&dev->class->subsys.kset.kobj, &dev->kobj,
				  dev->bus_id);
	}
	put_device(dev);

	kfree(new_class_name);
	kfree(old_symlink_name);
1056 1057
 out_free_old_class:
	kfree(old_class_name);
1058 1059 1060

	return error;
}
1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072


static int device_move_class_links(struct device *dev,
				   struct device *old_parent,
				   struct device *new_parent)
{
#ifdef CONFIG_SYSFS_DEPRECATED
	int error;
	char *class_name;

	class_name = make_class_name(dev->class->name, &dev->kobj);
	if (!class_name) {
1073
		error = -ENOMEM;
1074 1075 1076 1077 1078 1079
		goto out;
	}
	if (old_parent) {
		sysfs_remove_link(&dev->kobj, "device");
		sysfs_remove_link(&old_parent->kobj, class_name);
	}
1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091
	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;
1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102
out:
	kfree(class_name);
	return error;
#else
	return 0;
#endif
}

/**
 * device_move - moves a device to a new parent
 * @dev: the pointer to the struct device to be moved
1103
 * @new_parent: the new parent of the device (can by NULL)
1104 1105 1106 1107 1108
 */
int device_move(struct device *dev, struct device *new_parent)
{
	int error;
	struct device *old_parent;
1109
	struct kobject *new_parent_kobj;
1110 1111 1112 1113 1114 1115

	dev = get_device(dev);
	if (!dev)
		return -EINVAL;

	new_parent = get_device(new_parent);
1116 1117 1118 1119
	new_parent_kobj = get_device_parent (dev, new_parent);
	if (IS_ERR(new_parent_kobj)) {
		error = PTR_ERR(new_parent_kobj);
		put_device(new_parent);
1120 1121 1122
		goto out;
	}
	pr_debug("DEVICE: moving '%s' to '%s'\n", dev->bus_id,
1123 1124
		 new_parent ? new_parent->bus_id : "<NULL>");
	error = kobject_move(&dev->kobj, new_parent_kobj);
1125 1126 1127 1128 1129 1130 1131
	if (error) {
		put_device(new_parent);
		goto out;
	}
	old_parent = dev->parent;
	dev->parent = new_parent;
	if (old_parent)
1132
		klist_remove(&dev->knode_parent);
1133 1134
	if (new_parent)
		klist_add_tail(&dev->knode_parent, &new_parent->klist_children);
1135 1136 1137 1138 1139 1140 1141
	if (!dev->class)
		goto out_put;
	error = device_move_class_links(dev, old_parent, new_parent);
	if (error) {
		/* We ignore errors on cleanup since we're hosed anyway... */
		device_move_class_links(dev, new_parent, old_parent);
		if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
1142 1143
			if (new_parent)
				klist_remove(&dev->knode_parent);
1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158
			if (old_parent)
				klist_add_tail(&dev->knode_parent,
					       &old_parent->klist_children);
		}
		put_device(new_parent);
		goto out;
	}
out_put:
	put_device(old_parent);
out:
	put_device(dev);
	return error;
}

EXPORT_SYMBOL_GPL(device_move);