core.c 46.0 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 <linux/genhd.h>
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#include <linux/kallsyms.h>
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#include <linux/mutex.h>
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#include <linux/async.h>
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#include "base.h"
#include "power/power.h"

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#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

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int (*platform_notify)(struct device *dev) = NULL;
int (*platform_notify_remove)(struct device *dev) = NULL;
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static struct kobject *dev_kobj;
struct kobject *sysfs_dev_char_kobj;
struct kobject *sysfs_dev_block_kobj;
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#ifdef CONFIG_BLOCK
static inline int device_is_not_partition(struct device *dev)
{
	return !(dev->type == &part_type);
}
#else
static inline int device_is_not_partition(struct device *dev)
{
	return 1;
}
#endif
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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.
 */
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const char *dev_driver_string(const struct device *dev)
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{
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	struct device_driver *drv;

	/* dev->driver can change to NULL underneath us because of unbinding,
	 * so be careful about accessing it.  dev->bus and dev->class should
	 * never change once they are set, so they don't need special care.
	 */
	drv = ACCESS_ONCE(dev->driver);
	return drv ? drv->name :
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			(dev->bus ? dev->bus->name :
			(dev->class ? dev->class->name : ""));
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}
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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)

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static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
			     char *buf)
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{
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	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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	if (ret >= (ssize_t)PAGE_SIZE) {
		print_symbol("dev_attr_show: %s returned bad count\n",
				(unsigned long)dev_attr->show);
	}
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	return ret;
}

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static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
			      const char *buf, size_t count)
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{
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	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;
}

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static const struct sysfs_ops dev_sysfs_ops = {
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	.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.
 */
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static void device_release(struct kobject *kobj)
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{
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	struct device *dev = to_dev(kobj);
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	struct device_private *p = dev->p;
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	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
		WARN(1, KERN_ERR "Device '%s' does not have a release() "
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			"function, it is broken and must be fixed.\n",
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			dev_name(dev));
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	kfree(p);
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}

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static const void *device_namespace(struct kobject *kobj)
{
	struct device *dev = to_dev(kobj);
	const void *ns = NULL;

	if (dev->class && dev->class->ns_type)
		ns = dev->class->namespace(dev);

	return ns;
}

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static struct kobj_type device_ktype = {
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	.release	= device_release,
	.sysfs_ops	= &dev_sysfs_ops,
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	.namespace	= device_namespace,
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};


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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);

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	if (ktype == &device_ktype) {
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		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,
		      struct kobj_uevent_env *env)
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{
	struct device *dev = to_dev(kobj);
	int retval = 0;

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	/* add device node properties if present */
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	if (MAJOR(dev->devt)) {
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		const char *tmp;
		const char *name;
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		mode_t mode = 0;
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		add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
		add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
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		name = device_get_devnode(dev, &mode, &tmp);
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		if (name) {
			add_uevent_var(env, "DEVNAME=%s", name);
			kfree(tmp);
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			if (mode)
				add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
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		}
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	}

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	if (dev->type && dev->type->name)
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		add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
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	if (dev->driver)
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		add_uevent_var(env, "DRIVER=%s", dev->driver->name);
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	/* have the bus specific function add its stuff */
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	if (dev->bus && dev->bus->uevent) {
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		retval = dev->bus->uevent(dev, env);
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		if (retval)
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			pr_debug("device: '%s': %s: bus uevent() returned %d\n",
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				 dev_name(dev), __func__, retval);
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	}

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	/* have the class specific function add its stuff */
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	if (dev->class && dev->class->dev_uevent) {
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		retval = dev->class->dev_uevent(dev, env);
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		if (retval)
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			pr_debug("device: '%s': %s: class uevent() "
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				 "returned %d\n", dev_name(dev),
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				 __func__, retval);
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	}

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	/* have the device type specific function add its stuff */
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	if (dev->type && dev->type->uevent) {
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		retval = dev->type->uevent(dev, env);
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		if (retval)
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			pr_debug("device: '%s': %s: dev_type uevent() "
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				 "returned %d\n", dev_name(dev),
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				 __func__, retval);
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	}

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	return retval;
}

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

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static ssize_t show_uevent(struct device *dev, struct device_attribute *attr,
			   char *buf)
{
	struct kobject *top_kobj;
	struct kset *kset;
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	struct kobj_uevent_env *env = NULL;
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	int i;
	size_t count = 0;
	int retval;

	/* search the kset, the device belongs to */
	top_kobj = &dev->kobj;
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	while (!top_kobj->kset && top_kobj->parent)
		top_kobj = top_kobj->parent;
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	if (!top_kobj->kset)
		goto out;
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	kset = top_kobj->kset;
	if (!kset->uevent_ops || !kset->uevent_ops->uevent)
		goto out;

	/* respect filter */
	if (kset->uevent_ops && kset->uevent_ops->filter)
		if (!kset->uevent_ops->filter(kset, &dev->kobj))
			goto out;

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	env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
	if (!env)
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		return -ENOMEM;

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	/* let the kset specific function add its keys */
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	retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
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	if (retval)
		goto out;

	/* copy keys to file */
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	for (i = 0; i < env->envp_idx; i++)
		count += sprintf(&buf[count], "%s\n", env->envp[i]);
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out:
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	kfree(env);
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	return count;
}

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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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	enum kobject_action action;

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	if (kobject_action_type(buf, count, &action) == 0)
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		kobject_uevent(&dev->kobj, action);
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	else
		dev_err(dev, "uevent: unknown action-string\n");
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	return count;
}

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static struct device_attribute uevent_attr =
	__ATTR(uevent, S_IRUGO | S_IWUSR, show_uevent, store_uevent);

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static int device_add_attributes(struct device *dev,
				 struct device_attribute *attrs)
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{
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	int error = 0;
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	int i;
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	if (attrs) {
		for (i = 0; attr_name(attrs[i]); i++) {
			error = device_create_file(dev, &attrs[i]);
			if (error)
				break;
		}
		if (error)
			while (--i >= 0)
				device_remove_file(dev, &attrs[i]);
	}
	return error;
}

static void device_remove_attributes(struct device *dev,
				     struct device_attribute *attrs)
{
	int i;

	if (attrs)
		for (i = 0; attr_name(attrs[i]); i++)
			device_remove_file(dev, &attrs[i]);
}

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static int device_add_bin_attributes(struct device *dev,
				     struct bin_attribute *attrs)
{
	int error = 0;
	int i;

	if (attrs) {
		for (i = 0; attr_name(attrs[i]); i++) {
			error = device_create_bin_file(dev, &attrs[i]);
			if (error)
				break;
		}
		if (error)
			while (--i >= 0)
				device_remove_bin_file(dev, &attrs[i]);
	}
	return error;
}

static void device_remove_bin_attributes(struct device *dev,
					 struct bin_attribute *attrs)
{
	int i;

	if (attrs)
		for (i = 0; attr_name(attrs[i]); i++)
			device_remove_bin_file(dev, &attrs[i]);
}

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static int device_add_groups(struct device *dev,
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			     const struct attribute_group **groups)
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{
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	int error = 0;
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	int i;
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	if (groups) {
		for (i = 0; groups[i]; i++) {
			error = sysfs_create_group(&dev->kobj, groups[i]);
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			if (error) {
				while (--i >= 0)
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					sysfs_remove_group(&dev->kobj,
							   groups[i]);
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				break;
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			}
		}
	}
	return error;
}

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

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static int device_add_attrs(struct device *dev)
{
	struct class *class = dev->class;
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	const struct device_type *type = dev->type;
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	int error;
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	if (class) {
		error = device_add_attributes(dev, class->dev_attrs);
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		if (error)
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			return error;
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		error = device_add_bin_attributes(dev, class->dev_bin_attrs);
		if (error)
			goto err_remove_class_attrs;
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	}
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	if (type) {
		error = device_add_groups(dev, type->groups);
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		if (error)
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			goto err_remove_class_bin_attrs;
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	}

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	error = device_add_groups(dev, dev->groups);
	if (error)
		goto err_remove_type_groups;

	return 0;

 err_remove_type_groups:
	if (type)
		device_remove_groups(dev, type->groups);
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 err_remove_class_bin_attrs:
	if (class)
		device_remove_bin_attributes(dev, class->dev_bin_attrs);
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 err_remove_class_attrs:
	if (class)
		device_remove_attributes(dev, class->dev_attrs);

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	return error;
}

static void device_remove_attrs(struct device *dev)
{
	struct class *class = dev->class;
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	const struct device_type *type = dev->type;
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	device_remove_groups(dev, dev->groups);
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	if (type)
		device_remove_groups(dev, type->groups);

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	if (class) {
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		device_remove_attributes(dev, class->dev_attrs);
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		device_remove_bin_attributes(dev, class->dev_bin_attrs);
	}
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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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static struct device_attribute devt_attr =
	__ATTR(dev, S_IRUGO, show_dev, NULL);

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/* kset to create /sys/devices/  */
struct kset *devices_kset;
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/**
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 * device_create_file - create sysfs attribute file for device.
 * @dev: device.
 * @attr: device attribute descriptor.
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 */
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int device_create_file(struct device *dev,
		       const struct device_attribute *attr)
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{
	int error = 0;
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	if (dev)
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		error = sysfs_create_file(&dev->kobj, &attr->attr);
	return error;
}

/**
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 * device_remove_file - remove sysfs attribute file.
 * @dev: device.
 * @attr: device attribute descriptor.
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 */
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void device_remove_file(struct device *dev,
			const struct device_attribute *attr)
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{
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	if (dev)
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		sysfs_remove_file(&dev->kobj, &attr->attr);
}

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

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/**
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 * device_schedule_callback_owner - helper to schedule a callback for a device
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 * @dev: device.
 * @func: callback function to invoke later.
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 * @owner: module owning the callback routine
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 *
 * Attribute methods must not unregister themselves or their parent device
 * (which would amount to the same thing).  Attempts to do so will deadlock,
 * since unregistration is mutually exclusive with driver callbacks.
 *
 * Instead methods can call this routine, which will attempt to allocate
 * and schedule a workqueue request to call back @func with @dev as its
 * argument in the workqueue's process context.  @dev will be pinned until
 * @func returns.
 *
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 * This routine is usually called via the inline device_schedule_callback(),
 * which automatically sets @owner to THIS_MODULE.
 *
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 * Returns 0 if the request was submitted, -ENOMEM if storage could not
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 * be allocated, -ENODEV if a reference to @owner isn't available.
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 *
 * NOTE: This routine won't work if CONFIG_SYSFS isn't set!  It uses an
 * underlying sysfs routine (since it is intended for use by attribute
 * methods), and if sysfs isn't available you'll get nothing but -ENOSYS.
 */
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int device_schedule_callback_owner(struct device *dev,
		void (*func)(struct device *), struct module *owner)
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{
	return sysfs_schedule_callback(&dev->kobj,
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			(void (*)(void *)) func, dev, owner);
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}
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EXPORT_SYMBOL_GPL(device_schedule_callback_owner);
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static void klist_children_get(struct klist_node *n)
{
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	struct device_private *p = to_device_private_parent(n);
	struct device *dev = p->device;
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	get_device(dev);
}

static void klist_children_put(struct klist_node *n)
{
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	struct device_private *p = to_device_private_parent(n);
	struct device *dev = p->device;
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	put_device(dev);
}

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/**
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 * device_initialize - init device structure.
 * @dev: device.
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 *
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 * This prepares the device for use by other layers by initializing
 * its fields.
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 * It is the first half of device_register(), if called by
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 * that function, though it can also be called separately, so one
 * may use @dev's fields. In particular, get_device()/put_device()
 * may be used for reference counting of @dev after calling this
 * function.
 *
 * NOTE: Use put_device() to give up your reference instead of freeing
 * @dev directly once you have called this function.
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 */
void device_initialize(struct device *dev)
{
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	dev->kobj.kset = devices_kset;
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	kobject_init(&dev->kobj, &device_ktype);
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	INIT_LIST_HEAD(&dev->dma_pools);
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	mutex_init(&dev->mutex);
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	lockdep_set_novalidate_class(&dev->mutex);
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	spin_lock_init(&dev->devres_lock);
	INIT_LIST_HEAD(&dev->devres_head);
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	device_pm_init(dev);
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	set_dev_node(dev, -1);
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}

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static struct kobject *virtual_device_parent(struct device *dev)
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{
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	static struct kobject *virtual_dir = NULL;
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	if (!virtual_dir)
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		virtual_dir = kobject_create_and_add("virtual",
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						     &devices_kset->kobj);
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	return virtual_dir;
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}

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struct class_dir {
	struct kobject kobj;
	struct class *class;
};

#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)

static void class_dir_release(struct kobject *kobj)
{
	struct class_dir *dir = to_class_dir(kobj);
	kfree(dir);
}

static const
struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
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{
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	struct class_dir *dir = to_class_dir(kobj);
	return dir->class->ns_type;
}

static struct kobj_type class_dir_ktype = {
	.release	= class_dir_release,
	.sysfs_ops	= &kobj_sysfs_ops,
	.child_ns_type	= class_dir_child_ns_type
};

static struct kobject *
class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
{
	struct class_dir *dir;
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	int retval;

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	dir = kzalloc(sizeof(*dir), GFP_KERNEL);
	if (!dir)
		return NULL;

	dir->class = class;
	kobject_init(&dir->kobj, &class_dir_ktype);

650
	dir->kobj.kset = &class->p->glue_dirs;
651 652 653 654 655 656 657 658 659 660 661 662 663

	retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
	if (retval < 0) {
		kobject_put(&dir->kobj);
		return NULL;
	}
	return &dir->kobj;
}


static struct kobject *get_device_parent(struct device *dev,
					 struct device *parent)
{
664
	if (dev->class) {
665
		static DEFINE_MUTEX(gdp_mutex);
666 667 668 669
		struct kobject *kobj = NULL;
		struct kobject *parent_kobj;
		struct kobject *k;

670
#ifdef CONFIG_BLOCK
671
		/* block disks show up in /sys/block */
672
		if (sysfs_deprecated && dev->class == &block_class) {
673 674
			if (parent && parent->class == &block_class)
				return &parent->kobj;
675
			return &block_class.p->subsys.kobj;
676
		}
677
#endif
678

679 680
		/*
		 * If we have no parent, we live in "virtual".
681 682
		 * Class-devices with a non class-device as parent, live
		 * in a "glue" directory to prevent namespace collisions.
683 684 685
		 */
		if (parent == NULL)
			parent_kobj = virtual_device_parent(dev);
686
		else if (parent->class && !dev->class->ns_type)
687 688 689 690
			return &parent->kobj;
		else
			parent_kobj = &parent->kobj;

691 692
		mutex_lock(&gdp_mutex);

693
		/* find our class-directory at the parent and reference it */
694 695
		spin_lock(&dev->class->p->glue_dirs.list_lock);
		list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
696 697 698 699
			if (k->parent == parent_kobj) {
				kobj = kobject_get(k);
				break;
			}
700
		spin_unlock(&dev->class->p->glue_dirs.list_lock);
701 702
		if (kobj) {
			mutex_unlock(&gdp_mutex);
703
			return kobj;
704
		}
705 706

		/* or create a new class-directory at the parent device */
707
		k = class_dir_create_and_add(dev->class, parent_kobj);
708
		/* do not emit an uevent for this simple "glue" directory */
709
		mutex_unlock(&gdp_mutex);
710
		return k;
711 712 713
	}

	if (parent)
714 715 716
		return &parent->kobj;
	return NULL;
}
717

718
static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
719
{
720
	/* see if we live in a "glue" directory */
721
	if (!glue_dir || !dev->class ||
722
	    glue_dir->kset != &dev->class->p->glue_dirs)
723 724
		return;

725
	kobject_put(glue_dir);
726
}
727 728 729 730 731

static void cleanup_device_parent(struct device *dev)
{
	cleanup_glue_dir(dev, dev->kobj.parent);
}
732

733
static void setup_parent(struct device *dev, struct device *parent)
734 735 736 737 738
{
	struct kobject *kobj;
	kobj = get_device_parent(dev, parent);
	if (kobj)
		dev->kobj.parent = kobj;
739 740
}

741 742 743 744 745 746
static int device_add_class_symlinks(struct device *dev)
{
	int error;

	if (!dev->class)
		return 0;
747

748
	error = sysfs_create_link(&dev->kobj,
749
				  &dev->class->p->subsys.kobj,
750 751 752
				  "subsystem");
	if (error)
		goto out;
753

754
	if (dev->parent && device_is_not_partition(dev)) {
755
		error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
756 757
					  "device");
		if (error)
758
			goto out_subsys;
759 760
	}

761
#ifdef CONFIG_BLOCK
762
	/* /sys/block has directories and does not need symlinks */
763
	if (sysfs_deprecated && dev->class == &block_class)
764
		return 0;
765
#endif
766

767
	/* link in the class directory pointing to the device */
768
	error = sysfs_create_link(&dev->class->p->subsys.kobj,
769
				  &dev->kobj, dev_name(dev));
770
	if (error)
771
		goto out_device;
772 773 774

	return 0;

775 776
out_device:
	sysfs_remove_link(&dev->kobj, "device");
777

778 779 780 781 782 783 784 785 786 787
out_subsys:
	sysfs_remove_link(&dev->kobj, "subsystem");
out:
	return error;
}

static void device_remove_class_symlinks(struct device *dev)
{
	if (!dev->class)
		return;
788

789
	if (dev->parent && device_is_not_partition(dev))
790
		sysfs_remove_link(&dev->kobj, "device");
791
	sysfs_remove_link(&dev->kobj, "subsystem");
792
#ifdef CONFIG_BLOCK
793
	if (sysfs_deprecated && dev->class == &block_class)
794
		return;
795
#endif
796
	sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
797 798
}

799 800 801
/**
 * dev_set_name - set a device name
 * @dev: device
802
 * @fmt: format string for the device's name
803 804 805 806
 */
int dev_set_name(struct device *dev, const char *fmt, ...)
{
	va_list vargs;
807
	int err;
808 809

	va_start(vargs, fmt);
810
	err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
811
	va_end(vargs);
812
	return err;
813 814 815
}
EXPORT_SYMBOL_GPL(dev_set_name);

816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863
/**
 * device_to_dev_kobj - select a /sys/dev/ directory for the device
 * @dev: device
 *
 * By default we select char/ for new entries.  Setting class->dev_obj
 * to NULL prevents an entry from being created.  class->dev_kobj must
 * be set (or cleared) before any devices are registered to the class
 * otherwise device_create_sys_dev_entry() and
 * device_remove_sys_dev_entry() will disagree about the the presence
 * of the link.
 */
static struct kobject *device_to_dev_kobj(struct device *dev)
{
	struct kobject *kobj;

	if (dev->class)
		kobj = dev->class->dev_kobj;
	else
		kobj = sysfs_dev_char_kobj;

	return kobj;
}

static int device_create_sys_dev_entry(struct device *dev)
{
	struct kobject *kobj = device_to_dev_kobj(dev);
	int error = 0;
	char devt_str[15];

	if (kobj) {
		format_dev_t(devt_str, dev->devt);
		error = sysfs_create_link(kobj, &dev->kobj, devt_str);
	}

	return error;
}

static void device_remove_sys_dev_entry(struct device *dev)
{
	struct kobject *kobj = device_to_dev_kobj(dev);
	char devt_str[15];

	if (kobj) {
		format_dev_t(devt_str, dev->devt);
		sysfs_remove_link(kobj, devt_str);
	}
}

864 865 866 867 868 869 870 871 872 873 874
int device_private_init(struct device *dev)
{
	dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
	if (!dev->p)
		return -ENOMEM;
	dev->p->device = dev;
	klist_init(&dev->p->klist_children, klist_children_get,
		   klist_children_put);
	return 0;
}

L
Linus Torvalds 已提交
875
/**
876 877
 * device_add - add device to device hierarchy.
 * @dev: device.
L
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878
 *
879 880
 * This is part 2 of device_register(), though may be called
 * separately _iff_ device_initialize() has been called separately.
L
Linus Torvalds 已提交
881
 *
882
 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
883 884
 * to the global and sibling lists for the device, then
 * adds it to the other relevant subsystems of the driver model.
885 886 887 888
 *
 * NOTE: _Never_ directly free @dev after calling this function, even
 * if it returned an error! Always use put_device() to give up your
 * reference instead.
L
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889 890 891 892
 */
int device_add(struct device *dev)
{
	struct device *parent = NULL;
893
	struct class_interface *class_intf;
894
	int error = -EINVAL;
895

L
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896
	dev = get_device(dev);
897 898 899
	if (!dev)
		goto done;

900
	if (!dev->p) {
901 902 903
		error = device_private_init(dev);
		if (error)
			goto done;
904 905
	}

906 907 908 909 910 911
	/*
	 * for statically allocated devices, which should all be converted
	 * some day, we need to initialize the name. We prevent reading back
	 * the name, and force the use of dev_name()
	 */
	if (dev->init_name) {
912
		dev_set_name(dev, "%s", dev->init_name);
913 914
		dev->init_name = NULL;
	}
915

916 917
	if (!dev_name(dev)) {
		error = -EINVAL;
918
		goto name_error;
919
	}
L
Linus Torvalds 已提交
920

921
	pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
922

L
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923
	parent = get_device(dev->parent);
924
	setup_parent(dev, parent);
L
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925

926 927 928 929
	/* use parent numa_node */
	if (parent)
		set_dev_node(dev, dev_to_node(parent));

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930
	/* first, register with generic layer. */
931 932
	/* we require the name to be set before, and pass NULL */
	error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
933
	if (error)
L
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934
		goto Error;
935

936 937 938 939
	/* notify platform of device entry */
	if (platform_notify)
		platform_notify(dev);

940
	error = device_create_file(dev, &uevent_attr);
941 942
	if (error)
		goto attrError;
943

944
	if (MAJOR(dev->devt)) {
945 946
		error = device_create_file(dev, &devt_attr);
		if (error)
947
			goto ueventattrError;
948 949 950 951

		error = device_create_sys_dev_entry(dev);
		if (error)
			goto devtattrError;
952 953

		devtmpfs_create_node(dev);
954 955
	}

956 957 958
	error = device_add_class_symlinks(dev);
	if (error)
		goto SymlinkError;
959 960
	error = device_add_attrs(dev);
	if (error)
961
		goto AttrsError;
962 963
	error = bus_add_device(dev);
	if (error)
L
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964
		goto BusError;
965
	error = dpm_sysfs_add(dev);
966
	if (error)
967 968
		goto DPMError;
	device_pm_add(dev);
969 970 971 972 973 974 975 976

	/* Notify clients of device addition.  This call must come
	 * after dpm_sysf_add() and before kobject_uevent().
	 */
	if (dev->bus)
		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
					     BUS_NOTIFY_ADD_DEVICE, dev);

977
	kobject_uevent(&dev->kobj, KOBJ_ADD);
978
	bus_probe_device(dev);
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979
	if (parent)
980 981
		klist_add_tail(&dev->p->knode_parent,
			       &parent->p->klist_children);
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982

983
	if (dev->class) {
984
		mutex_lock(&dev->class->p->class_mutex);
985
		/* tie the class to the device */
986
		klist_add_tail(&dev->knode_class,
987
			       &dev->class->p->klist_devices);
988 989

		/* notify any interfaces that the device is here */
990 991
		list_for_each_entry(class_intf,
				    &dev->class->p->class_interfaces, node)
992 993
			if (class_intf->add_dev)
				class_intf->add_dev(dev, class_intf);
994
		mutex_unlock(&dev->class->p->class_mutex);
995
	}
996
done:
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997 998
	put_device(dev);
	return error;
999
 DPMError:
1000 1001
	bus_remove_device(dev);
 BusError:
1002
	device_remove_attrs(dev);
1003
 AttrsError:
1004 1005
	device_remove_class_symlinks(dev);
 SymlinkError:
1006 1007
	if (MAJOR(dev->devt))
		devtmpfs_delete_node(dev);
1008 1009 1010
	if (MAJOR(dev->devt))
		device_remove_sys_dev_entry(dev);
 devtattrError:
1011 1012
	if (MAJOR(dev->devt))
		device_remove_file(dev, &devt_attr);
1013
 ueventattrError:
1014
	device_remove_file(dev, &uevent_attr);
1015
 attrError:
1016
	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
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1017 1018
	kobject_del(&dev->kobj);
 Error:
1019
	cleanup_device_parent(dev);
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1020 1021
	if (parent)
		put_device(parent);
1022 1023 1024
name_error:
	kfree(dev->p);
	dev->p = NULL;
1025
	goto done;
L
Linus Torvalds 已提交
1026 1027 1028
}

/**
1029 1030
 * device_register - register a device with the system.
 * @dev: pointer to the device structure
L
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1031
 *
1032 1033 1034 1035 1036 1037
 * 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.
1038 1039 1040 1041
 *
 * NOTE: _Never_ directly free @dev after calling this function, even
 * if it returned an error! Always use put_device() to give up the
 * reference initialized in this function instead.
L
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1042 1043 1044 1045 1046 1047 1048 1049
 */
int device_register(struct device *dev)
{
	device_initialize(dev);
	return device_add(dev);
}

/**
1050 1051
 * get_device - increment reference count for device.
 * @dev: device.
L
Linus Torvalds 已提交
1052
 *
1053 1054 1055
 * 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.
L
Linus Torvalds 已提交
1056
 */
1057
struct device *get_device(struct device *dev)
L
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1058 1059 1060 1061 1062
{
	return dev ? to_dev(kobject_get(&dev->kobj)) : NULL;
}

/**
1063 1064
 * put_device - decrement reference count.
 * @dev: device in question.
L
Linus Torvalds 已提交
1065
 */
1066
void put_device(struct device *dev)
L
Linus Torvalds 已提交
1067
{
1068
	/* might_sleep(); */
L
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1069 1070 1071 1072 1073
	if (dev)
		kobject_put(&dev->kobj);
}

/**
1074 1075
 * device_del - delete device from system.
 * @dev: device.
L
Linus Torvalds 已提交
1076
 *
1077 1078 1079 1080 1081
 * 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.
L
Linus Torvalds 已提交
1082
 *
1083 1084
 * NOTE: this should be called manually _iff_ device_add() was
 * also called manually.
L
Linus Torvalds 已提交
1085
 */
1086
void device_del(struct device *dev)
L
Linus Torvalds 已提交
1087
{
1088
	struct device *parent = dev->parent;
1089
	struct class_interface *class_intf;
L
Linus Torvalds 已提交
1090

1091 1092 1093 1094 1095 1096
	/* Notify clients of device removal.  This call must come
	 * before dpm_sysfs_remove().
	 */
	if (dev->bus)
		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
					     BUS_NOTIFY_DEL_DEVICE, dev);
1097
	device_pm_remove(dev);
1098
	dpm_sysfs_remove(dev);
L
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1099
	if (parent)
1100
		klist_del(&dev->p->knode_parent);
1101
	if (MAJOR(dev->devt)) {
1102
		devtmpfs_delete_node(dev);
1103
		device_remove_sys_dev_entry(dev);
1104
		device_remove_file(dev, &devt_attr);
1105
	}
1106
	if (dev->class) {
1107
		device_remove_class_symlinks(dev);
1108

1109
		mutex_lock(&dev->class->p->class_mutex);
1110
		/* notify any interfaces that the device is now gone */
1111 1112
		list_for_each_entry(class_intf,
				    &dev->class->p->class_interfaces, node)
1113 1114 1115
			if (class_intf->remove_dev)
				class_intf->remove_dev(dev, class_intf);
		/* remove the device from the class list */
1116
		klist_del(&dev->knode_class);
1117
		mutex_unlock(&dev->class->p->class_mutex);
1118
	}
1119
	device_remove_file(dev, &uevent_attr);
1120
	device_remove_attrs(dev);
1121
	bus_remove_device(dev);
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1122

1123 1124 1125 1126 1127 1128 1129
	/*
	 * Some platform devices are driven without driver attached
	 * and managed resources may have been acquired.  Make sure
	 * all resources are released.
	 */
	devres_release_all(dev);

L
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1130 1131 1132 1133 1134
	/* Notify the platform of the removal, in case they
	 * need to do anything...
	 */
	if (platform_notify_remove)
		platform_notify_remove(dev);
1135
	kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1136
	cleanup_device_parent(dev);
L
Linus Torvalds 已提交
1137
	kobject_del(&dev->kobj);
1138
	put_device(parent);
L
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1139 1140 1141
}

/**
1142 1143
 * device_unregister - unregister device from system.
 * @dev: device going away.
L
Linus Torvalds 已提交
1144
 *
1145 1146 1147 1148 1149 1150
 * 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.
L
Linus Torvalds 已提交
1151
 */
1152
void device_unregister(struct device *dev)
L
Linus Torvalds 已提交
1153
{
1154
	pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
L
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1155 1156 1157 1158
	device_del(dev);
	put_device(dev);
}

1159
static struct device *next_device(struct klist_iter *i)
1160
{
1161
	struct klist_node *n = klist_next(i);
1162 1163 1164 1165 1166 1167 1168 1169
	struct device *dev = NULL;
	struct device_private *p;

	if (n) {
		p = to_device_private_parent(n);
		dev = p->device;
	}
	return dev;
1170 1171
}

1172
/**
1173
 * device_get_devnode - path of device node file
1174
 * @dev: device
1175
 * @mode: returned file access mode
1176 1177 1178 1179 1180 1181 1182
 * @tmp: possibly allocated string
 *
 * Return the relative path of a possible device node.
 * Non-default names may need to allocate a memory to compose
 * a name. This memory is returned in tmp and needs to be
 * freed by the caller.
 */
1183 1184
const char *device_get_devnode(struct device *dev,
			       mode_t *mode, const char **tmp)
1185 1186 1187 1188 1189 1190
{
	char *s;

	*tmp = NULL;

	/* the device type may provide a specific name */
1191 1192
	if (dev->type && dev->type->devnode)
		*tmp = dev->type->devnode(dev, mode);
1193 1194 1195 1196
	if (*tmp)
		return *tmp;

	/* the class may provide a specific name */
1197 1198
	if (dev->class && dev->class->devnode)
		*tmp = dev->class->devnode(dev, mode);
1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214
	if (*tmp)
		return *tmp;

	/* return name without allocation, tmp == NULL */
	if (strchr(dev_name(dev), '!') == NULL)
		return dev_name(dev);

	/* replace '!' in the name with '/' */
	*tmp = kstrdup(dev_name(dev), GFP_KERNEL);
	if (!*tmp)
		return NULL;
	while ((s = strchr(*tmp, '!')))
		s[0] = '/';
	return *tmp;
}

L
Linus Torvalds 已提交
1215
/**
1216 1217 1218 1219
 * device_for_each_child - device child iterator.
 * @parent: parent struct device.
 * @data: data for the callback.
 * @fn: function to be called for each device.
L
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1220
 *
1221 1222
 * Iterate over @parent's child devices, and call @fn for each,
 * passing it @data.
L
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1223
 *
1224 1225
 * We check the return of @fn each time. If it returns anything
 * other than 0, we break out and return that value.
L
Linus Torvalds 已提交
1226
 */
1227 1228
int device_for_each_child(struct device *parent, void *data,
			  int (*fn)(struct device *dev, void *data))
L
Linus Torvalds 已提交
1229
{
1230
	struct klist_iter i;
1231
	struct device *child;
L
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1232 1233
	int error = 0;

1234 1235 1236
	if (!parent->p)
		return 0;

1237
	klist_iter_init(&parent->p->klist_children, &i);
1238 1239 1240
	while ((child = next_device(&i)) && !error)
		error = fn(child, data);
	klist_iter_exit(&i);
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1241 1242 1243
	return error;
}

1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258
/**
 * 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.
 */
1259 1260
struct device *device_find_child(struct device *parent, void *data,
				 int (*match)(struct device *dev, void *data))
1261 1262 1263 1264 1265 1266 1267
{
	struct klist_iter i;
	struct device *child;

	if (!parent)
		return NULL;

1268
	klist_iter_init(&parent->p->klist_children, &i);
1269 1270 1271 1272 1273 1274 1275
	while ((child = next_device(&i)))
		if (match(child, data) && get_device(child))
			break;
	klist_iter_exit(&i);
	return child;
}

L
Linus Torvalds 已提交
1276 1277
int __init devices_init(void)
{
1278 1279 1280
	devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
	if (!devices_kset)
		return -ENOMEM;
1281 1282 1283 1284 1285 1286 1287 1288 1289 1290
	dev_kobj = kobject_create_and_add("dev", NULL);
	if (!dev_kobj)
		goto dev_kobj_err;
	sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
	if (!sysfs_dev_block_kobj)
		goto block_kobj_err;
	sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
	if (!sysfs_dev_char_kobj)
		goto char_kobj_err;

1291
	return 0;
1292 1293 1294 1295 1296 1297 1298 1299

 char_kobj_err:
	kobject_put(sysfs_dev_block_kobj);
 block_kobj_err:
	kobject_put(dev_kobj);
 dev_kobj_err:
	kset_unregister(devices_kset);
	return -ENOMEM;
L
Linus Torvalds 已提交
1300 1301 1302
}

EXPORT_SYMBOL_GPL(device_for_each_child);
1303
EXPORT_SYMBOL_GPL(device_find_child);
L
Linus Torvalds 已提交
1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315

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);
1316

1317
struct root_device {
1318 1319 1320 1321
	struct device dev;
	struct module *owner;
};

1322 1323 1324 1325
inline struct root_device *to_root_device(struct device *d)
{
	return container_of(d, struct root_device, dev);
}
1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349

static void root_device_release(struct device *dev)
{
	kfree(to_root_device(dev));
}

/**
 * __root_device_register - allocate and register a root device
 * @name: root device name
 * @owner: owner module of the root device, usually THIS_MODULE
 *
 * This function allocates a root device and registers it
 * using device_register(). In order to free the returned
 * device, use root_device_unregister().
 *
 * Root devices are dummy devices which allow other devices
 * to be grouped under /sys/devices. Use this function to
 * allocate a root device and then use it as the parent of
 * any device which should appear under /sys/devices/{name}
 *
 * The /sys/devices/{name} directory will also contain a
 * 'module' symlink which points to the @owner directory
 * in sysfs.
 *
1350 1351
 * Returns &struct device pointer on success, or ERR_PTR() on error.
 *
1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362
 * Note: You probably want to use root_device_register().
 */
struct device *__root_device_register(const char *name, struct module *owner)
{
	struct root_device *root;
	int err = -ENOMEM;

	root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
	if (!root)
		return ERR_PTR(err);

1363
	err = dev_set_name(&root->dev, "%s", name);
1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376
	if (err) {
		kfree(root);
		return ERR_PTR(err);
	}

	root->dev.release = root_device_release;

	err = device_register(&root->dev);
	if (err) {
		put_device(&root->dev);
		return ERR_PTR(err);
	}

1377
#ifdef CONFIG_MODULES	/* gotta find a "cleaner" way to do this */
1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395
	if (owner) {
		struct module_kobject *mk = &owner->mkobj;

		err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
		if (err) {
			device_unregister(&root->dev);
			return ERR_PTR(err);
		}
		root->owner = owner;
	}
#endif

	return &root->dev;
}
EXPORT_SYMBOL_GPL(__root_device_register);

/**
 * root_device_unregister - unregister and free a root device
1396
 * @dev: device going away
1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411
 *
 * This function unregisters and cleans up a device that was created by
 * root_device_register().
 */
void root_device_unregister(struct device *dev)
{
	struct root_device *root = to_root_device(dev);

	if (root->owner)
		sysfs_remove_link(&root->dev.kobj, "module");

	device_unregister(dev);
}
EXPORT_SYMBOL_GPL(root_device_unregister);

1412 1413 1414

static void device_create_release(struct device *dev)
{
1415
	pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1416 1417 1418 1419
	kfree(dev);
}

/**
1420
 * device_create_vargs - creates a device and registers it with sysfs
1421 1422 1423
 * @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
1424
 * @drvdata: the data to be added to the device for callbacks
1425
 * @fmt: string for the device's name
1426
 * @args: va_list for the device's name
1427 1428 1429
 *
 * This function can be used by char device classes.  A struct device
 * will be created in sysfs, registered to the specified class.
1430 1431 1432
 *
 * A "dev" file will be created, showing the dev_t for the device, if
 * the dev_t is not 0,0.
1433 1434 1435 1436
 * 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
1437 1438
 * pointer.
 *
1439 1440
 * Returns &struct device pointer on success, or ERR_PTR() on error.
 *
1441 1442 1443
 * Note: the struct class passed to this function must have previously
 * been created with a call to class_create().
 */
1444 1445 1446
struct device *device_create_vargs(struct class *class, struct device *parent,
				   dev_t devt, void *drvdata, const char *fmt,
				   va_list args)
1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463
{
	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;
1464
	dev_set_drvdata(dev, drvdata);
1465

1466 1467 1468 1469
	retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
	if (retval)
		goto error;

1470 1471 1472 1473 1474 1475 1476
	retval = device_register(dev);
	if (retval)
		goto error;

	return dev;

error:
1477
	put_device(dev);
1478 1479
	return ERR_PTR(retval);
}
1480 1481 1482
EXPORT_SYMBOL_GPL(device_create_vargs);

/**
1483
 * device_create - creates a device and registers it with sysfs
1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500
 * @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
 * @drvdata: the data to be added to the device for callbacks
 * @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.
 *
 * A "dev" file will be created, showing the dev_t for the device, if
 * the dev_t is not 0,0.
 * 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
 * pointer.
 *
1501 1502
 * Returns &struct device pointer on success, or ERR_PTR() on error.
 *
1503 1504 1505
 * Note: the struct class passed to this function must have previously
 * been created with a call to class_create().
 */
1506 1507
struct device *device_create(struct class *class, struct device *parent,
			     dev_t devt, void *drvdata, const char *fmt, ...)
1508 1509 1510 1511 1512 1513 1514 1515 1516
{
	va_list vargs;
	struct device *dev;

	va_start(vargs, fmt);
	dev = device_create_vargs(class, parent, devt, drvdata, fmt, vargs);
	va_end(vargs);
	return dev;
}
1517
EXPORT_SYMBOL_GPL(device_create);
1518

1519
static int __match_devt(struct device *dev, void *data)
1520
{
1521
	dev_t *devt = data;
1522

1523
	return dev->devt == *devt;
1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536
}

/**
 * device_destroy - removes a device that was created with device_create()
 * @class: pointer to the struct class that this device was registered with
 * @devt: the dev_t of the device that was previously registered
 *
 * This call unregisters and cleans up a device that was created with a
 * call to device_create().
 */
void device_destroy(struct class *class, dev_t devt)
{
	struct device *dev;
1537

1538
	dev = class_find_device(class, NULL, &devt, __match_devt);
1539 1540
	if (dev) {
		put_device(dev);
1541
		device_unregister(dev);
1542
	}
1543 1544
}
EXPORT_SYMBOL_GPL(device_destroy);
1545 1546 1547 1548 1549

/**
 * device_rename - renames a device
 * @dev: the pointer to the struct device to be renamed
 * @new_name: the new name of the device
1550 1551 1552 1553 1554
 *
 * It is the responsibility of the caller to provide mutual
 * exclusion between two different calls of device_rename
 * on the same device to ensure that new_name is valid and
 * won't conflict with other devices.
1555
 *
1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583
 * Note: Don't call this function.  Currently, the networking layer calls this
 * function, but that will change.  The following text from Kay Sievers offers
 * some insight:
 *
 * Renaming devices is racy at many levels, symlinks and other stuff are not
 * replaced atomically, and you get a "move" uevent, but it's not easy to
 * connect the event to the old and new device. Device nodes are not renamed at
 * all, there isn't even support for that in the kernel now.
 *
 * In the meantime, during renaming, your target name might be taken by another
 * driver, creating conflicts. Or the old name is taken directly after you
 * renamed it -- then you get events for the same DEVPATH, before you even see
 * the "move" event. It's just a mess, and nothing new should ever rely on
 * kernel device renaming. Besides that, it's not even implemented now for
 * other things than (driver-core wise very simple) network devices.
 *
 * We are currently about to change network renaming in udev to completely
 * disallow renaming of devices in the same namespace as the kernel uses,
 * because we can't solve the problems properly, that arise with swapping names
 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only
 * be allowed to some other name than eth[0-9]*, for the aforementioned
 * reasons.
 *
 * Make up a "real" name in the driver before you register anything, or add
 * some other attributes for userspace to find the device, or use udev to add
 * symlinks -- but never rename kernel devices later, it's a complete mess. We
 * don't even want to get into that and try to implement the missing pieces in
 * the core. We really have other pieces to fix in the driver core mess. :)
1584
 */
1585
int device_rename(struct device *dev, const char *new_name)
1586 1587 1588
{
	char *old_class_name = NULL;
	char *new_class_name = NULL;
1589
	char *old_device_name = NULL;
1590 1591 1592 1593 1594 1595
	int error;

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

1596
	pr_debug("device: '%s': %s: renaming to '%s'\n", dev_name(dev),
1597
		 __func__, new_name);
1598

1599
	old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
1600 1601 1602
	if (!old_device_name) {
		error = -ENOMEM;
		goto out;
1603 1604
	}

1605
	if (dev->class) {
1606
		error = sysfs_rename_link(&dev->class->p->subsys.kobj,
1607 1608 1609 1610
			&dev->kobj, old_device_name, new_name);
		if (error)
			goto out;
	}
1611

1612
	error = kobject_rename(&dev->kobj, new_name);
1613
	if (error)
1614
		goto out;
1615

1616
out:
1617 1618 1619
	put_device(dev);

	kfree(new_class_name);
1620
	kfree(old_class_name);
1621
	kfree(old_device_name);
1622 1623 1624

	return error;
}
1625
EXPORT_SYMBOL_GPL(device_rename);
1626 1627 1628 1629 1630

static int device_move_class_links(struct device *dev,
				   struct device *old_parent,
				   struct device *new_parent)
{
1631
	int error = 0;
1632

1633 1634 1635 1636 1637 1638
	if (old_parent)
		sysfs_remove_link(&dev->kobj, "device");
	if (new_parent)
		error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
					  "device");
	return error;
1639 1640 1641 1642 1643
}

/**
 * device_move - moves a device to a new parent
 * @dev: the pointer to the struct device to be moved
1644
 * @new_parent: the new parent of the device (can by NULL)
1645
 * @dpm_order: how to reorder the dpm_list
1646
 */
1647 1648
int device_move(struct device *dev, struct device *new_parent,
		enum dpm_order dpm_order)
1649 1650 1651
{
	int error;
	struct device *old_parent;
1652
	struct kobject *new_parent_kobj;
1653 1654 1655 1656 1657

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

1658
	device_pm_lock();
1659
	new_parent = get_device(new_parent);
1660
	new_parent_kobj = get_device_parent(dev, new_parent);
1661

1662 1663
	pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
		 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
1664
	error = kobject_move(&dev->kobj, new_parent_kobj);
1665
	if (error) {
1666
		cleanup_glue_dir(dev, new_parent_kobj);
1667 1668 1669 1670 1671 1672
		put_device(new_parent);
		goto out;
	}
	old_parent = dev->parent;
	dev->parent = new_parent;
	if (old_parent)
1673
		klist_remove(&dev->p->knode_parent);
1674
	if (new_parent) {
1675 1676
		klist_add_tail(&dev->p->knode_parent,
			       &new_parent->p->klist_children);
1677 1678 1679
		set_dev_node(dev, dev_to_node(new_parent));
	}

1680 1681 1682 1683 1684 1685 1686
	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)) {
1687
			if (new_parent)
1688
				klist_remove(&dev->p->knode_parent);
1689 1690
			dev->parent = old_parent;
			if (old_parent) {
1691 1692
				klist_add_tail(&dev->p->knode_parent,
					       &old_parent->p->klist_children);
1693 1694
				set_dev_node(dev, dev_to_node(old_parent));
			}
1695
		}
1696
		cleanup_glue_dir(dev, new_parent_kobj);
1697 1698 1699
		put_device(new_parent);
		goto out;
	}
1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712
	switch (dpm_order) {
	case DPM_ORDER_NONE:
		break;
	case DPM_ORDER_DEV_AFTER_PARENT:
		device_pm_move_after(dev, new_parent);
		break;
	case DPM_ORDER_PARENT_BEFORE_DEV:
		device_pm_move_before(new_parent, dev);
		break;
	case DPM_ORDER_DEV_LAST:
		device_pm_move_last(dev);
		break;
	}
1713 1714 1715
out_put:
	put_device(old_parent);
out:
1716
	device_pm_unlock();
1717 1718 1719 1720
	put_device(dev);
	return error;
}
EXPORT_SYMBOL_GPL(device_move);
1721 1722 1723 1724 1725 1726

/**
 * device_shutdown - call ->shutdown() on each device to shutdown.
 */
void device_shutdown(void)
{
1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744
	struct device *dev;

	spin_lock(&devices_kset->list_lock);
	/*
	 * Walk the devices list backward, shutting down each in turn.
	 * Beware that device unplug events may also start pulling
	 * devices offline, even as the system is shutting down.
	 */
	while (!list_empty(&devices_kset->list)) {
		dev = list_entry(devices_kset->list.prev, struct device,
				kobj.entry);
		get_device(dev);
		/*
		 * Make sure the device is off the kset list, in the
		 * event that dev->*->shutdown() doesn't remove it.
		 */
		list_del_init(&dev->kobj.entry);
		spin_unlock(&devices_kset->list_lock);
1745 1746 1747 1748 1749 1750 1751 1752

		if (dev->bus && dev->bus->shutdown) {
			dev_dbg(dev, "shutdown\n");
			dev->bus->shutdown(dev);
		} else if (dev->driver && dev->driver->shutdown) {
			dev_dbg(dev, "shutdown\n");
			dev->driver->shutdown(dev);
		}
1753 1754 1755
		put_device(dev);

		spin_lock(&devices_kset->list_lock);
1756
	}
1757
	spin_unlock(&devices_kset->list_lock);
1758
	async_synchronize_full();
1759
}
1760 1761 1762 1763 1764 1765 1766

/*
 * Device logging functions
 */

#ifdef CONFIG_PRINTK

1767 1768
int __dev_printk(const char *level, const struct device *dev,
		 struct va_format *vaf)
1769 1770 1771 1772 1773 1774 1775
{
	if (!dev)
		return printk("%s(NULL device *): %pV", level, vaf);

	return printk("%s%s %s: %pV",
		      level, dev_driver_string(dev), dev_name(dev), vaf);
}
1776
EXPORT_SYMBOL(__dev_printk);
1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824

int dev_printk(const char *level, const struct device *dev,
	       const char *fmt, ...)
{
	struct va_format vaf;
	va_list args;
	int r;

	va_start(args, fmt);

	vaf.fmt = fmt;
	vaf.va = &args;

	r = __dev_printk(level, dev, &vaf);
	va_end(args);

	return r;
}
EXPORT_SYMBOL(dev_printk);

#define define_dev_printk_level(func, kern_level)		\
int func(const struct device *dev, const char *fmt, ...)	\
{								\
	struct va_format vaf;					\
	va_list args;						\
	int r;							\
								\
	va_start(args, fmt);					\
								\
	vaf.fmt = fmt;						\
	vaf.va = &args;						\
								\
	r = __dev_printk(kern_level, dev, &vaf);		\
	va_end(args);						\
								\
	return r;						\
}								\
EXPORT_SYMBOL(func);

define_dev_printk_level(dev_emerg, KERN_EMERG);
define_dev_printk_level(dev_alert, KERN_ALERT);
define_dev_printk_level(dev_crit, KERN_CRIT);
define_dev_printk_level(dev_err, KERN_ERR);
define_dev_printk_level(dev_warn, KERN_WARNING);
define_dev_printk_level(dev_notice, KERN_NOTICE);
define_dev_printk_level(_dev_info, KERN_INFO);

#endif