[mirror_ubuntu-artful-kernel.git] / lib / kobject.c

/*
 * kobject.c - library routines for handling generic kernel objects
 *
 * Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org>
 *
 * This file is released under the GPLv2.
 *
 *
 * Please see the file Documentation/kobject.txt for critical information
 * about using the kobject interface.
 */

#include <linux/kobject.h>
#include <linux/string.h>
#include <linux/module.h>
#include <linux/stat.h>
#include <linux/slab.h>

/**
 *	populate_dir - populate directory with attributes.
 *	@kobj:	object we're working on.
 *
 *	Most subsystems have a set of default attributes that 
 *	are associated with an object that registers with them.
 *	This is a helper called during object registration that 
 *	loops through the default attributes of the subsystem 
 *	and creates attributes files for them in sysfs.
 *
 */

static int populate_dir(struct kobject * kobj)
{
	struct kobj_type * t = get_ktype(kobj);
	struct attribute * attr;
	int error = 0;
	int i;
	
	if (t && t->default_attrs) {
		for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) {
			if ((error = sysfs_create_file(kobj,attr)))
				break;
		}
	}
	return error;
}

static int create_dir(struct kobject * kobj)
{
	int error = 0;
	if (kobject_name(kobj)) {
		error = sysfs_create_dir(kobj);
		if (!error) {
			if ((error = populate_dir(kobj)))
				sysfs_remove_dir(kobj);
		}
	}
	return error;
}

static inline struct kobject * to_kobj(struct list_head * entry)
{
	return container_of(entry,struct kobject,entry);
}

static int get_kobj_path_length(struct kobject *kobj)
{
	int length = 1;
	struct kobject * parent = kobj;

	/* walk up the ancestors until we hit the one pointing to the 
	 * root.
	 * Add 1 to strlen for leading '/' of each level.
	 */
	do {
		if (kobject_name(parent) == NULL)
			return 0;
		length += strlen(kobject_name(parent)) + 1;
		parent = parent->parent;
	} while (parent);
	return length;
}

static void fill_kobj_path(struct kobject *kobj, char *path, int length)
{
	struct kobject * parent;

	--length;
	for (parent = kobj; parent; parent = parent->parent) {
		int cur = strlen(kobject_name(parent));
		/* back up enough to print this name with '/' */
		length -= cur;
		strncpy (path + length, kobject_name(parent), cur);
		*(path + --length) = '/';
	}

	pr_debug("%s: path = '%s'\n",__FUNCTION__,path);
}

/**
 * kobject_get_path - generate and return the path associated with a given kobj
 * and kset pair.  The result must be freed by the caller with kfree().
 *
 * @kobj:	kobject in question, with which to build the path
 * @gfp_mask:	the allocation type used to allocate the path
 */
char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
{
	char *path;
	int len;

	len = get_kobj_path_length(kobj);
	if (len == 0)
		return NULL;
	path = kmalloc(len, gfp_mask);
	if (!path)
		return NULL;
	memset(path, 0x00, len);
	fill_kobj_path(kobj, path, len);

	return path;
}

/**
 *	kobject_init - initialize object.
 *	@kobj:	object in question.
 */
void kobject_init(struct kobject * kobj)
{
	kref_init(&kobj->kref);
	INIT_LIST_HEAD(&kobj->entry);
	init_waitqueue_head(&kobj->poll);
	kobj->kset = kset_get(kobj->kset);
}


/**
 *	unlink - remove kobject from kset list.
 *	@kobj:	kobject.
 *
 *	Remove the kobject from the kset list and decrement
 *	its parent's refcount.
 *	This is separated out, so we can use it in both 
 *	kobject_del() and kobject_add() on error.
 */

static void unlink(struct kobject * kobj)
{
	if (kobj->kset) {
		spin_lock(&kobj->kset->list_lock);
		list_del_init(&kobj->entry);
		spin_unlock(&kobj->kset->list_lock);
	}
	kobject_put(kobj);
}

/**
 *	kobject_add - add an object to the hierarchy.
 *	@kobj:	object.
 */

int kobject_add(struct kobject * kobj)
{
	int error = 0;
	struct kobject * parent;

	if (!(kobj = kobject_get(kobj)))
		return -ENOENT;
	if (!kobj->k_name)
		kobj->k_name = kobj->name;
	if (!kobj->k_name) {
		pr_debug("kobject attempted to be registered with no name!\n");
		WARN_ON(1);
		return -EINVAL;
	}
	parent = kobject_get(kobj->parent);

	pr_debug("kobject %s: registering. parent: %s, set: %s\n",
		 kobject_name(kobj), parent ? kobject_name(parent) : "<NULL>", 
		 kobj->kset ? kobj->kset->kobj.name : "<NULL>" );

	if (kobj->kset) {
		spin_lock(&kobj->kset->list_lock);

		if (!parent)
			parent = kobject_get(&kobj->kset->kobj);

		list_add_tail(&kobj->entry,&kobj->kset->list);
		spin_unlock(&kobj->kset->list_lock);
	}
	kobj->parent = parent;

	error = create_dir(kobj);
	if (error) {
		/* unlink does the kobject_put() for us */
		unlink(kobj);
		if (parent)
			kobject_put(parent);

		/* be noisy on error issues */
		if (error == -EEXIST)
			printk("kobject_add failed for %s with -EEXIST, "
			       "don't try to register things with the "
			       "same name in the same directory.\n",
			       kobject_name(kobj));
		else
			printk("kobject_add failed for %s (%d)\n",
			       kobject_name(kobj), error);
		 dump_stack();
	}

	return error;
}


/**
 *	kobject_register - initialize and add an object.
 *	@kobj:	object in question.
 */

int kobject_register(struct kobject * kobj)
{
	int error = -EINVAL;
	if (kobj) {
		kobject_init(kobj);
		error = kobject_add(kobj);
		if (!error)
			kobject_uevent(kobj, KOBJ_ADD);
	}
	return error;
}


/**
 *	kobject_set_name - Set the name of an object
 *	@kobj:	object.
 *	@fmt:	format string used to build the name
 *
 *	If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated
 *	string that @kobj->k_name points to. Otherwise, use the static 
 *	@kobj->name array.
 */
int kobject_set_name(struct kobject * kobj, const char * fmt, ...)
{
	int error = 0;
	int limit = KOBJ_NAME_LEN;
	int need;
	va_list args;
	char * name;

	/* 
	 * First, try the static array 
	 */
	va_start(args,fmt);
	need = vsnprintf(kobj->name,limit,fmt,args);
	va_end(args);
	if (need < limit) 
		name = kobj->name;
	else {
		/* 
		 * Need more space? Allocate it and try again 
		 */
		limit = need + 1;
		name = kmalloc(limit,GFP_KERNEL);
		if (!name) {
			error = -ENOMEM;
			goto Done;
		}
		va_start(args,fmt);
		need = vsnprintf(name,limit,fmt,args);
		va_end(args);

		/* Still? Give up. */
		if (need >= limit) {
			kfree(name);
			error = -EFAULT;
			goto Done;
		}
	}

	/* Free the old name, if necessary. */
	if (kobj->k_name && kobj->k_name != kobj->name)
		kfree(kobj->k_name);

	/* Now, set the new name */
	kobj->k_name = name;
 Done:
	return error;
}

EXPORT_SYMBOL(kobject_set_name);


/**
 *	kobject_rename - change the name of an object
 *	@kobj:	object in question.
 *	@new_name: object's new name
 */

int kobject_rename(struct kobject * kobj, const char *new_name)
{
	int error = 0;

	kobj = kobject_get(kobj);
	if (!kobj)
		return -EINVAL;
	error = sysfs_rename_dir(kobj, new_name);
	kobject_put(kobj);

	return error;
}

/**
 *	kobject_del - unlink kobject from hierarchy.
 * 	@kobj:	object.
 */

void kobject_del(struct kobject * kobj)
{
	sysfs_remove_dir(kobj);
	unlink(kobj);
}

/**
 *	kobject_unregister - remove object from hierarchy and decrement refcount.
 *	@kobj:	object going away.
 */

void kobject_unregister(struct kobject * kobj)
{
	pr_debug("kobject %s: unregistering\n",kobject_name(kobj));
	kobject_uevent(kobj, KOBJ_REMOVE);
	kobject_del(kobj);
	kobject_put(kobj);
}

/**
 *	kobject_get - increment refcount for object.
 *	@kobj:	object.
 */

struct kobject * kobject_get(struct kobject * kobj)
{
	if (kobj)
		kref_get(&kobj->kref);
	return kobj;
}

/**
 *	kobject_cleanup - free kobject resources. 
 *	@kobj:	object.
 */

void kobject_cleanup(struct kobject * kobj)
{
	struct kobj_type * t = get_ktype(kobj);
	struct kset * s = kobj->kset;
	struct kobject * parent = kobj->parent;

	pr_debug("kobject %s: cleaning up\n",kobject_name(kobj));
	if (kobj->k_name != kobj->name)
		kfree(kobj->k_name);
	kobj->k_name = NULL;
	if (t && t->release)
		t->release(kobj);
	if (s)
		kset_put(s);
	if (parent) 
		kobject_put(parent);
}

static void kobject_release(struct kref *kref)
{
	kobject_cleanup(container_of(kref, struct kobject, kref));
}

/**
 *	kobject_put - decrement refcount for object.
 *	@kobj:	object.
 *
 *	Decrement the refcount, and if 0, call kobject_cleanup().
 */
void kobject_put(struct kobject * kobj)
{
	if (kobj)
		kref_put(&kobj->kref, kobject_release);
}


static void dir_release(struct kobject *kobj)
{
	kfree(kobj);
}

static struct kobj_type dir_ktype = {
	.release	= dir_release,
	.sysfs_ops	= NULL,
	.default_attrs	= NULL,
};

/**
 *	kobject_add_dir - add sub directory of object.
 *	@parent:	object in which a directory is created.
 *	@name:	directory name.
 *
 *	Add a plain directory object as child of given object.
 */
struct kobject *kobject_add_dir(struct kobject *parent, const char *name)
{
	struct kobject *k;
	int ret;

	if (!parent)
		return NULL;

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

	k->parent = parent;
	k->ktype = &dir_ktype;
	kobject_set_name(k, name);
	ret = kobject_register(k);
	if (ret < 0) {
		printk(KERN_WARNING "kobject_add_dir: "
			"kobject_register error: %d\n", ret);
		kobject_del(k);
		return NULL;
	}

	return k;
}

/**
 *	kset_init - initialize a kset for use
 *	@k:	kset 
 */

void kset_init(struct kset * k)
{
	kobject_init(&k->kobj);
	INIT_LIST_HEAD(&k->list);
	spin_lock_init(&k->list_lock);
}


/**
 *	kset_add - add a kset object to the hierarchy.
 *	@k:	kset.
 *
 *	Simply, this adds the kset's embedded kobject to the 
 *	hierarchy. 
 *	We also try to make sure that the kset's embedded kobject
 *	has a parent before it is added. We only care if the embedded
 *	kobject is not part of a kset itself, since kobject_add()
 *	assigns a parent in that case. 
 *	If that is the case, and the kset has a controlling subsystem,
 *	then we set the kset's parent to be said subsystem. 
 */

int kset_add(struct kset * k)
{
	if (!k->kobj.parent && !k->kobj.kset && k->subsys)
		k->kobj.parent = &k->subsys->kset.kobj;

	return kobject_add(&k->kobj);
}


/**
 *	kset_register - initialize and add a kset.
 *	@k:	kset.
 */

int kset_register(struct kset * k)
{
	kset_init(k);
	return kset_add(k);
}


/**
 *	kset_unregister - remove a kset.
 *	@k:	kset.
 */

void kset_unregister(struct kset * k)
{
	kobject_unregister(&k->kobj);
}


/**
 *	kset_find_obj - search for object in kset.
 *	@kset:	kset we're looking in.
 *	@name:	object's name.
 *
 *	Lock kset via @kset->subsys, and iterate over @kset->list,
 *	looking for a matching kobject. If matching object is found
 *	take a reference and return the object.
 */

struct kobject * kset_find_obj(struct kset * kset, const char * name)
{
	struct list_head * entry;
	struct kobject * ret = NULL;

	spin_lock(&kset->list_lock);
	list_for_each(entry,&kset->list) {
		struct kobject * k = to_kobj(entry);
		if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
			ret = kobject_get(k);
			break;
		}
	}
	spin_unlock(&kset->list_lock);
	return ret;
}


void subsystem_init(struct subsystem * s)
{
	init_rwsem(&s->rwsem);
	kset_init(&s->kset);
}

/**
 *	subsystem_register - register a subsystem.
 *	@s:	the subsystem we're registering.
 *
 *	Once we register the subsystem, we want to make sure that 
 *	the kset points back to this subsystem for correct usage of 
 *	the rwsem. 
 */

int subsystem_register(struct subsystem * s)
{
	int error;

	subsystem_init(s);
	pr_debug("subsystem %s: registering\n",s->kset.kobj.name);

	if (!(error = kset_add(&s->kset))) {
		if (!s->kset.subsys)
			s->kset.subsys = s;
	}
	return error;
}

void subsystem_unregister(struct subsystem * s)
{
	pr_debug("subsystem %s: unregistering\n",s->kset.kobj.name);
	kset_unregister(&s->kset);
}


/**
 *	subsystem_create_file - export sysfs attribute file.
 *	@s:	subsystem.
 *	@a:	subsystem attribute descriptor.
 */

int subsys_create_file(struct subsystem * s, struct subsys_attribute * a)
{
	int error = 0;
	if (subsys_get(s)) {
		error = sysfs_create_file(&s->kset.kobj,&a->attr);
		subsys_put(s);
	}
	return error;
}


/**
 *	subsystem_remove_file - remove sysfs attribute file.
 *	@s:	subsystem.
 *	@a:	attribute desciptor.
 */
#if 0
void subsys_remove_file(struct subsystem * s, struct subsys_attribute * a)
{
	if (subsys_get(s)) {
		sysfs_remove_file(&s->kset.kobj,&a->attr);
		subsys_put(s);
	}
}
#endif  /*  0  */

EXPORT_SYMBOL(kobject_init);
EXPORT_SYMBOL(kobject_register);
EXPORT_SYMBOL(kobject_unregister);
EXPORT_SYMBOL(kobject_get);
EXPORT_SYMBOL(kobject_put);
EXPORT_SYMBOL(kobject_add);
EXPORT_SYMBOL(kobject_del);

EXPORT_SYMBOL(kset_register);
EXPORT_SYMBOL(kset_unregister);

EXPORT_SYMBOL(subsystem_register);
EXPORT_SYMBOL(subsystem_unregister);
EXPORT_SYMBOL(subsys_create_file);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* kobject.c - library routines for handling generic kernel objects
	3	*
	4	* Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org>
	5	*
	6	* This file is released under the GPLv2.
	7	*
	8	*
	9	* Please see the file Documentation/kobject.txt for critical information
	10	* about using the kobject interface.
	11	*/
	12
	13	#include <linux/kobject.h>
	14	#include <linux/string.h>
	15	#include <linux/module.h>
	16	#include <linux/stat.h>
4e57b681	17	#include <linux/slab.h>
1da177e4 LT	18
	19	/**
	20	* populate_dir - populate directory with attributes.
	21	* @kobj: object we're working on.
	22	*
	23	* Most subsystems have a set of default attributes that
	24	* are associated with an object that registers with them.
	25	* This is a helper called during object registration that
	26	* loops through the default attributes of the subsystem
	27	* and creates attributes files for them in sysfs.
	28	*
	29	*/
	30
	31	static int populate_dir(struct kobject * kobj)
	32	{
	33	struct kobj_type * t = get_ktype(kobj);
	34	struct attribute * attr;
	35	int error = 0;
	36	int i;
	37
	38	if (t && t->default_attrs) {
	39	for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) {
	40	if ((error = sysfs_create_file(kobj,attr)))
	41	break;
	42	}
	43	}
	44	return error;
	45	}
	46
	47	static int create_dir(struct kobject * kobj)
	48	{
	49	int error = 0;
	50	if (kobject_name(kobj)) {
	51	error = sysfs_create_dir(kobj);
	52	if (!error) {
	53	if ((error = populate_dir(kobj)))
	54	sysfs_remove_dir(kobj);
	55	}
	56	}
	57	return error;
	58	}
	59
	60	static inline struct kobject * to_kobj(struct list_head * entry)
	61	{
	62	return container_of(entry,struct kobject,entry);
	63	}
	64
	65	static int get_kobj_path_length(struct kobject *kobj)
	66	{
	67	int length = 1;
	68	struct kobject * parent = kobj;
	69
	70	/* walk up the ancestors until we hit the one pointing to the
	71	* root.
	72	* Add 1 to strlen for leading '/' of each level.
	73	*/
	74	do {
b365b3da CE	75	if (kobject_name(parent) == NULL)
b365b3da CE	76	return 0;
1da177e4 LT	77	length += strlen(kobject_name(parent)) + 1;
	78	parent = parent->parent;
	79	} while (parent);
	80	return length;
	81	}
	82
	83	static void fill_kobj_path(struct kobject kobj, char path, int length)
	84	{
	85	struct kobject * parent;
	86
	87	--length;
	88	for (parent = kobj; parent; parent = parent->parent) {
	89	int cur = strlen(kobject_name(parent));
	90	/* back up enough to print this name with '/' */
	91	length -= cur;
	92	strncpy (path + length, kobject_name(parent), cur);
	93	*(path + --length) = '/';
	94	}
	95
	96	pr_debug("%s: path = '%s'\n",__FUNCTION__,path);
	97	}
	98
	99	/**
	100	* kobject_get_path - generate and return the path associated with a given kobj
	101	* and kset pair. The result must be freed by the caller with kfree().
	102	*
	103	* @kobj: kobject in question, with which to build the path
	104	* @gfp_mask: the allocation type used to allocate the path
	105	*/
fd4f2df2	106	char kobject_get_path(struct kobject kobj, gfp_t gfp_mask)
1da177e4 LT	107	{
	108	char *path;
	109	int len;
	110
	111	len = get_kobj_path_length(kobj);
b365b3da CE	112	if (len == 0)
b365b3da CE	113	return NULL;
1da177e4 LT	114	path = kmalloc(len, gfp_mask);
	115	if (!path)
	116	return NULL;
	117	memset(path, 0x00, len);
	118	fill_kobj_path(kobj, path, len);
	119
	120	return path;
	121	}
	122
	123	/**
	124	* kobject_init - initialize object.
	125	* @kobj: object in question.
	126	*/
	127	void kobject_init(struct kobject * kobj)
	128	{
	129	kref_init(&kobj->kref);
	130	INIT_LIST_HEAD(&kobj->entry);
4508a7a7	131	init_waitqueue_head(&kobj->poll);
1da177e4 LT	132	kobj->kset = kset_get(kobj->kset);
	133	}
	134
	135
	136	/**
	137	* unlink - remove kobject from kset list.
	138	* @kobj: kobject.
	139	*
	140	* Remove the kobject from the kset list and decrement
	141	* its parent's refcount.
	142	* This is separated out, so we can use it in both
	143	* kobject_del() and kobject_add() on error.
	144	*/
	145
	146	static void unlink(struct kobject * kobj)
	147	{
	148	if (kobj->kset) {
	149	spin_lock(&kobj->kset->list_lock);
	150	list_del_init(&kobj->entry);
	151	spin_unlock(&kobj->kset->list_lock);
	152	}
	153	kobject_put(kobj);
	154	}
	155
	156	/**
	157	* kobject_add - add an object to the hierarchy.
	158	* @kobj: object.
	159	*/
	160
	161	int kobject_add(struct kobject * kobj)
	162	{
	163	int error = 0;
	164	struct kobject * parent;
	165
	166	if (!(kobj = kobject_get(kobj)))
	167	return -ENOENT;
	168	if (!kobj->k_name)
	169	kobj->k_name = kobj->name;
c171fef5 GKH	170	if (!kobj->k_name) {
	171	pr_debug("kobject attempted to be registered with no name!\n");
	172	WARN_ON(1);
	173	return -EINVAL;
	174	}
1da177e4 LT	175	parent = kobject_get(kobj->parent);
	176
	177	pr_debug("kobject %s: registering. parent: %s, set: %s\n",
	178	kobject_name(kobj), parent ? kobject_name(parent) : "<NULL>",
	179	kobj->kset ? kobj->kset->kobj.name : "<NULL>" );
	180
	181	if (kobj->kset) {
	182	spin_lock(&kobj->kset->list_lock);
	183
	184	if (!parent)
	185	parent = kobject_get(&kobj->kset->kobj);
	186
	187	list_add_tail(&kobj->entry,&kobj->kset->list);
	188	spin_unlock(&kobj->kset->list_lock);
	189	}
	190	kobj->parent = parent;
	191
	192	error = create_dir(kobj);
	193	if (error) {
	194	/* unlink does the kobject_put() for us */
	195	unlink(kobj);
	196	if (parent)
	197	kobject_put(parent);
dcd0da00 GKH	198
	199	/* be noisy on error issues */
	200	if (error == -EEXIST)
183bd5b3	201	printk("kobject_add failed for %s with -EEXIST, "
dcd0da00 GKH	202	"don't try to register things with the "
	203	"same name in the same directory.\n",
	204	kobject_name(kobj));
	205	else
183bd5b3	206	printk("kobject_add failed for %s (%d)\n",
dcd0da00	207	kobject_name(kobj), error);
183bd5b3	208	dump_stack();
1da177e4 LT	209	}
	210
	211	return error;
	212	}
	213
	214
	215	/**
	216	* kobject_register - initialize and add an object.
	217	* @kobj: object in question.
	218	*/
	219
	220	int kobject_register(struct kobject * kobj)
	221	{
dcd0da00	222	int error = -EINVAL;
1da177e4 LT	223	if (kobj) {
	224	kobject_init(kobj);
	225	error = kobject_add(kobj);
dcd0da00	226	if (!error)
312c004d	227	kobject_uevent(kobj, KOBJ_ADD);
dcd0da00	228	}
1da177e4 LT	229	return error;
	230	}
	231
	232
	233	/**
	234	* kobject_set_name - Set the name of an object
	235	* @kobj: object.
67be2dd1	236	* @fmt: format string used to build the name
1da177e4 LT	237	*
	238	* If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated
	239	* string that @kobj->k_name points to. Otherwise, use the static
	240	* @kobj->name array.
	241	*/
1da177e4 LT	242	int kobject_set_name(struct kobject * kobj, const char * fmt, ...)
	243	{
	244	int error = 0;
	245	int limit = KOBJ_NAME_LEN;
	246	int need;
	247	va_list args;
	248	char * name;
	249
	250	/*
	251	* First, try the static array
	252	*/
	253	va_start(args,fmt);
	254	need = vsnprintf(kobj->name,limit,fmt,args);
	255	va_end(args);
	256	if (need < limit)
	257	name = kobj->name;
	258	else {
	259	/*
	260	* Need more space? Allocate it and try again
	261	*/
	262	limit = need + 1;
	263	name = kmalloc(limit,GFP_KERNEL);
	264	if (!name) {
	265	error = -ENOMEM;
	266	goto Done;
	267	}
	268	va_start(args,fmt);
	269	need = vsnprintf(name,limit,fmt,args);
	270	va_end(args);
	271
	272	/* Still? Give up. */
	273	if (need >= limit) {
	274	kfree(name);
	275	error = -EFAULT;
	276	goto Done;
	277	}
	278	}
	279
	280	/* Free the old name, if necessary. */
	281	if (kobj->k_name && kobj->k_name != kobj->name)
	282	kfree(kobj->k_name);
	283
	284	/* Now, set the new name */
	285	kobj->k_name = name;
	286	Done:
	287	return error;
	288	}
	289
	290	EXPORT_SYMBOL(kobject_set_name);
	291
	292
	293	/**
	294	* kobject_rename - change the name of an object
	295	* @kobj: object in question.
	296	* @new_name: object's new name
	297	*/
	298
f3b4f3c6	299	int kobject_rename(struct kobject * kobj, const char *new_name)
1da177e4 LT	300	{
	301	int error = 0;
	302
	303	kobj = kobject_get(kobj);
	304	if (!kobj)
	305	return -EINVAL;
	306	error = sysfs_rename_dir(kobj, new_name);
	307	kobject_put(kobj);
	308
	309	return error;
	310	}
	311
	312	/**
	313	* kobject_del - unlink kobject from hierarchy.
	314	* @kobj: object.
	315	*/
	316
	317	void kobject_del(struct kobject * kobj)
	318	{
1da177e4 LT	319	sysfs_remove_dir(kobj);
	320	unlink(kobj);
	321	}
	322
	323	/**
	324	* kobject_unregister - remove object from hierarchy and decrement refcount.
	325	* @kobj: object going away.
	326	*/
	327
	328	void kobject_unregister(struct kobject * kobj)
	329	{
	330	pr_debug("kobject %s: unregistering\n",kobject_name(kobj));
312c004d	331	kobject_uevent(kobj, KOBJ_REMOVE);
1da177e4 LT	332	kobject_del(kobj);
	333	kobject_put(kobj);
	334	}
	335
	336	/**
	337	* kobject_get - increment refcount for object.
	338	* @kobj: object.
	339	*/
	340
	341	struct kobject * kobject_get(struct kobject * kobj)
	342	{
	343	if (kobj)
	344	kref_get(&kobj->kref);
	345	return kobj;
	346	}
	347
	348	/**
	349	* kobject_cleanup - free kobject resources.
	350	* @kobj: object.
	351	*/
	352
	353	void kobject_cleanup(struct kobject * kobj)
	354	{
	355	struct kobj_type * t = get_ktype(kobj);
	356	struct kset * s = kobj->kset;
	357	struct kobject * parent = kobj->parent;
	358
	359	pr_debug("kobject %s: cleaning up\n",kobject_name(kobj));
	360	if (kobj->k_name != kobj->name)
	361	kfree(kobj->k_name);
	362	kobj->k_name = NULL;
	363	if (t && t->release)
	364	t->release(kobj);
	365	if (s)
	366	kset_put(s);
	367	if (parent)
	368	kobject_put(parent);
	369	}
	370
	371	static void kobject_release(struct kref *kref)
	372	{
	373	kobject_cleanup(container_of(kref, struct kobject, kref));
	374	}
	375
	376	/**
	377	* kobject_put - decrement refcount for object.
	378	* @kobj: object.
	379	*
	380	* Decrement the refcount, and if 0, call kobject_cleanup().
	381	*/
	382	void kobject_put(struct kobject * kobj)
	383	{
	384	if (kobj)
	385	kref_put(&kobj->kref, kobject_release);
	386	}
	387
	388
7423172a JN	389	static void dir_release(struct kobject *kobj)
	390	{
	391	kfree(kobj);
	392	}
	393
	394	static struct kobj_type dir_ktype = {
	395	.release = dir_release,
	396	.sysfs_ops = NULL,
	397	.default_attrs = NULL,
	398	};
	399
	400	/**
	401	* kobject_add_dir - add sub directory of object.
	402	* @parent: object in which a directory is created.
	403	* @name: directory name.
	404	*
	405	* Add a plain directory object as child of given object.
	406	*/
	407	struct kobject kobject_add_dir(struct kobject parent, const char *name)
	408	{
	409	struct kobject *k;
10188012	410	int ret;
7423172a JN	411
	412	if (!parent)
	413	return NULL;
	414
	415	k = kzalloc(sizeof(*k), GFP_KERNEL);
	416	if (!k)
	417	return NULL;
	418
	419	k->parent = parent;
	420	k->ktype = &dir_ktype;
	421	kobject_set_name(k, name);
10188012 RD	422	ret = kobject_register(k);
	423	if (ret < 0) {
	424	printk(KERN_WARNING "kobject_add_dir: "
	425	"kobject_register error: %d\n", ret);
	426	kobject_del(k);
	427	return NULL;
	428	}
7423172a JN	429
	430	return k;
	431	}
7423172a	432
1da177e4 LT	433	/**
	434	* kset_init - initialize a kset for use
	435	* @k: kset
	436	*/
	437
	438	void kset_init(struct kset * k)
	439	{
	440	kobject_init(&k->kobj);
	441	INIT_LIST_HEAD(&k->list);
	442	spin_lock_init(&k->list_lock);
	443	}
	444
	445
	446	/**
	447	* kset_add - add a kset object to the hierarchy.
	448	* @k: kset.
	449	*
	450	* Simply, this adds the kset's embedded kobject to the
	451	* hierarchy.
	452	* We also try to make sure that the kset's embedded kobject
	453	* has a parent before it is added. We only care if the embedded
	454	* kobject is not part of a kset itself, since kobject_add()
	455	* assigns a parent in that case.
	456	* If that is the case, and the kset has a controlling subsystem,
	457	* then we set the kset's parent to be said subsystem.
	458	*/
	459
	460	int kset_add(struct kset * k)
	461	{
	462	if (!k->kobj.parent && !k->kobj.kset && k->subsys)
	463	k->kobj.parent = &k->subsys->kset.kobj;
	464
	465	return kobject_add(&k->kobj);
	466	}
	467
	468
	469	/**
	470	* kset_register - initialize and add a kset.
	471	* @k: kset.
	472	*/
	473
	474	int kset_register(struct kset * k)
	475	{
	476	kset_init(k);
	477	return kset_add(k);
	478	}
	479
	480
	481	/**
	482	* kset_unregister - remove a kset.
	483	* @k: kset.
	484	*/
	485
	486	void kset_unregister(struct kset * k)
	487	{
	488	kobject_unregister(&k->kobj);
	489	}
	490
	491
	492	/**
	493	* kset_find_obj - search for object in kset.
	494	* @kset: kset we're looking in.
	495	* @name: object's name.
	496	*
497	* Lock kset via @kset->subsys, and iterate over @kset->list,
498	* looking for a matching kobject. If matching object is found
499	* take a reference and return the object.
500	*/
501
502	struct kobject * kset_find_obj(struct kset * kset, const char * name)
503	{
504	struct list_head * entry;
505	struct kobject * ret = NULL;
506
507	spin_lock(&kset->list_lock);
508	list_for_each(entry,&kset->list) {
509	struct kobject * k = to_kobj(entry);
510	if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
511	ret = kobject_get(k);
512	break;
513	}
514	}
515	spin_unlock(&kset->list_lock);
516	return ret;
517	}
518
519
520	void subsystem_init(struct subsystem * s)
521	{
522	init_rwsem(&s->rwsem);
523	kset_init(&s->kset);
524	}
525
526	/**
527	* subsystem_register - register a subsystem.
528	* @s: the subsystem we're registering.
529	*
530	* Once we register the subsystem, we want to make sure that
531	* the kset points back to this subsystem for correct usage of
532	* the rwsem.
533	*/
534
535	int subsystem_register(struct subsystem * s)
536	{
537	int error;
538
539	subsystem_init(s);
540	pr_debug("subsystem %s: registering\n",s->kset.kobj.name);
541
542	if (!(error = kset_add(&s->kset))) {
543	if (!s->kset.subsys)
544	s->kset.subsys = s;
545	}
546	return error;
547	}
548
549	void subsystem_unregister(struct subsystem * s)
550	{
551	pr_debug("subsystem %s: unregistering\n",s->kset.kobj.name);
552	kset_unregister(&s->kset);
553	}
554
555
556	/**
557	* subsystem_create_file - export sysfs attribute file.
558	* @s: subsystem.
559	* @a: subsystem attribute descriptor.
560	*/
561
562	int subsys_create_file(struct subsystem * s, struct subsys_attribute * a)
563	{
564	int error = 0;
565	if (subsys_get(s)) {
566	error = sysfs_create_file(&s->kset.kobj,&a->attr);
567	subsys_put(s);
568	}
569	return error;
570	}
571
572
573	/**
574	* subsystem_remove_file - remove sysfs attribute file.
575	* @s: subsystem.
576	* @a: attribute desciptor.
577	*/
5b3ef14e	578	#if 0
1da177e4 LT	579	void subsys_remove_file(struct subsystem * s, struct subsys_attribute * a)
	580	{
	581	if (subsys_get(s)) {
	582	sysfs_remove_file(&s->kset.kobj,&a->attr);
	583	subsys_put(s);
	584	}
	585	}
5b3ef14e	586	#endif /* 0 */
1da177e4 LT	587
	588	EXPORT_SYMBOL(kobject_init);
	589	EXPORT_SYMBOL(kobject_register);
	590	EXPORT_SYMBOL(kobject_unregister);
	591	EXPORT_SYMBOL(kobject_get);
	592	EXPORT_SYMBOL(kobject_put);
	593	EXPORT_SYMBOL(kobject_add);
	594	EXPORT_SYMBOL(kobject_del);
	595
	596	EXPORT_SYMBOL(kset_register);
	597	EXPORT_SYMBOL(kset_unregister);
1da177e4	598
1da177e4 LT	599	EXPORT_SYMBOL(subsystem_register);
	600	EXPORT_SYMBOL(subsystem_unregister);
	601	EXPORT_SYMBOL(subsys_create_file);