[linux.git] / lib / kobject.c

/*
 * kobject.c - library routines for handling generic kernel objects
 *
 * Copyright (c) 2002-2003 Patrick Mochel <[email protected]>
 *
 * 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 {
		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);
	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);
	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;
	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);
	}

	return error;
}


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

int kobject_register(struct kobject * kobj)
{
	int error = 0;
	if (kobj) {
		kobject_init(kobj);
		error = kobject_add(kobj);
		if (error) {
			printk("kobject_register failed for %s (%d)\n",
			       kobject_name(kobj),error);
			dump_stack();
		} else
			kobject_hotplug(kobj, KOBJ_ADD);
	} else
		error = -EINVAL;
	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_hotplug(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);
}


/**
 *	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.
 */

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);
	}
}

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(kset_find_obj);

EXPORT_SYMBOL(subsystem_init);
EXPORT_SYMBOL(subsystem_register);
EXPORT_SYMBOL(subsystem_unregister);
EXPORT_SYMBOL(subsys_create_file);
EXPORT_SYMBOL(subsys_remove_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 <[email protected]>
	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 {
	75	length += strlen(kobject_name(parent)) + 1;
	76	parent = parent->parent;
	77	} while (parent);
	78	return length;
	79	}
	80
	81	static void fill_kobj_path(struct kobject kobj, char path, int length)
82	{
83	struct kobject * parent;
84
85	--length;
86	for (parent = kobj; parent; parent = parent->parent) {
87	int cur = strlen(kobject_name(parent));
88	/* back up enough to print this name with '/' */
89	length -= cur;
90	strncpy (path + length, kobject_name(parent), cur);
91	*(path + --length) = '/';
92	}
93
94	pr_debug("%s: path = '%s'\n",__FUNCTION__,path);
95	}
96
97	/**
98	* kobject_get_path - generate and return the path associated with a given kobj
99	* and kset pair. The result must be freed by the caller with kfree().
100	*
101	* @kobj: kobject in question, with which to build the path
102	* @gfp_mask: the allocation type used to allocate the path
103	*/
fd4f2df2	104	char kobject_get_path(struct kobject kobj, gfp_t gfp_mask)
1da177e4 LT	105	{
	106	char *path;
	107	int len;
	108
	109	len = get_kobj_path_length(kobj);
	110	path = kmalloc(len, gfp_mask);
	111	if (!path)
	112	return NULL;
	113	memset(path, 0x00, len);
	114	fill_kobj_path(kobj, path, len);
	115
	116	return path;
	117	}
	118
	119	/**
	120	* kobject_init - initialize object.
	121	* @kobj: object in question.
	122	*/
	123	void kobject_init(struct kobject * kobj)
	124	{
	125	kref_init(&kobj->kref);
	126	INIT_LIST_HEAD(&kobj->entry);
	127	kobj->kset = kset_get(kobj->kset);
	128	}
	129
	130
	131	/**
	132	* unlink - remove kobject from kset list.
	133	* @kobj: kobject.
	134	*
	135	* Remove the kobject from the kset list and decrement
	136	* its parent's refcount.
	137	* This is separated out, so we can use it in both
	138	* kobject_del() and kobject_add() on error.
	139	*/
	140
	141	static void unlink(struct kobject * kobj)
	142	{
	143	if (kobj->kset) {
	144	spin_lock(&kobj->kset->list_lock);
	145	list_del_init(&kobj->entry);
	146	spin_unlock(&kobj->kset->list_lock);
	147	}
	148	kobject_put(kobj);
	149	}
	150
	151	/**
	152	* kobject_add - add an object to the hierarchy.
	153	* @kobj: object.
	154	*/
	155
	156	int kobject_add(struct kobject * kobj)
	157	{
	158	int error = 0;
	159	struct kobject * parent;
	160
	161	if (!(kobj = kobject_get(kobj)))
	162	return -ENOENT;
	163	if (!kobj->k_name)
	164	kobj->k_name = kobj->name;
	165	parent = kobject_get(kobj->parent);
	166
	167	pr_debug("kobject %s: registering. parent: %s, set: %s\n",
	168	kobject_name(kobj), parent ? kobject_name(parent) : "<NULL>",
169	kobj->kset ? kobj->kset->kobj.name : "<NULL>" );
170
171	if (kobj->kset) {
172	spin_lock(&kobj->kset->list_lock);
173
174	if (!parent)
175	parent = kobject_get(&kobj->kset->kobj);
176
177	list_add_tail(&kobj->entry,&kobj->kset->list);
178	spin_unlock(&kobj->kset->list_lock);
179	}
180	kobj->parent = parent;
181
182	error = create_dir(kobj);
183	if (error) {
184	/* unlink does the kobject_put() for us */
185	unlink(kobj);
186	if (parent)
187	kobject_put(parent);
1da177e4 LT	188	}
	189
	190	return error;
	191	}
	192
	193
	194	/**
	195	* kobject_register - initialize and add an object.
	196	* @kobj: object in question.
	197	*/
	198
	199	int kobject_register(struct kobject * kobj)
	200	{
	201	int error = 0;
	202	if (kobj) {
	203	kobject_init(kobj);
	204	error = kobject_add(kobj);
	205	if (error) {
	206	printk("kobject_register failed for %s (%d)\n",
	207	kobject_name(kobj),error);
	208	dump_stack();
18c3d527 KS	209	} else
18c3d527 KS	210	kobject_hotplug(kobj, KOBJ_ADD);
1da177e4 LT	211	} else
	212	error = -EINVAL;
	213	return error;
	214	}
	215
	216
	217	/**
	218	* kobject_set_name - Set the name of an object
	219	* @kobj: object.
67be2dd1	220	* @fmt: format string used to build the name
1da177e4 LT	221	*
	222	* If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated
	223	* string that @kobj->k_name points to. Otherwise, use the static
	224	* @kobj->name array.
	225	*/
1da177e4 LT	226	int kobject_set_name(struct kobject * kobj, const char * fmt, ...)
	227	{
	228	int error = 0;
	229	int limit = KOBJ_NAME_LEN;
	230	int need;
	231	va_list args;
	232	char * name;
	233
	234	/*
	235	* First, try the static array
	236	*/
	237	va_start(args,fmt);
	238	need = vsnprintf(kobj->name,limit,fmt,args);
	239	va_end(args);
	240	if (need < limit)
	241	name = kobj->name;
	242	else {
	243	/*
	244	* Need more space? Allocate it and try again
	245	*/
	246	limit = need + 1;
	247	name = kmalloc(limit,GFP_KERNEL);
	248	if (!name) {
	249	error = -ENOMEM;
	250	goto Done;
	251	}
	252	va_start(args,fmt);
	253	need = vsnprintf(name,limit,fmt,args);
	254	va_end(args);
	255
	256	/* Still? Give up. */
	257	if (need >= limit) {
	258	kfree(name);
	259	error = -EFAULT;
	260	goto Done;
	261	}
	262	}
	263
	264	/* Free the old name, if necessary. */
	265	if (kobj->k_name && kobj->k_name != kobj->name)
	266	kfree(kobj->k_name);
	267
	268	/* Now, set the new name */
	269	kobj->k_name = name;
	270	Done:
	271	return error;
	272	}
	273
	274	EXPORT_SYMBOL(kobject_set_name);
	275
	276
	277	/**
	278	* kobject_rename - change the name of an object
	279	* @kobj: object in question.
	280	* @new_name: object's new name
	281	*/
	282
f3b4f3c6	283	int kobject_rename(struct kobject * kobj, const char *new_name)
1da177e4 LT	284	{
	285	int error = 0;
	286
	287	kobj = kobject_get(kobj);
	288	if (!kobj)
	289	return -EINVAL;
	290	error = sysfs_rename_dir(kobj, new_name);
	291	kobject_put(kobj);
	292
	293	return error;
	294	}
	295
	296	/**
	297	* kobject_del - unlink kobject from hierarchy.
	298	* @kobj: object.
	299	*/
	300
	301	void kobject_del(struct kobject * kobj)
	302	{
1da177e4 LT	303	sysfs_remove_dir(kobj);
	304	unlink(kobj);
	305	}
	306
	307	/**
	308	* kobject_unregister - remove object from hierarchy and decrement refcount.
	309	* @kobj: object going away.
	310	*/
	311
	312	void kobject_unregister(struct kobject * kobj)
	313	{
	314	pr_debug("kobject %s: unregistering\n",kobject_name(kobj));
18c3d527	315	kobject_hotplug(kobj, KOBJ_REMOVE);
1da177e4 LT	316	kobject_del(kobj);
	317	kobject_put(kobj);
	318	}
	319
	320	/**
	321	* kobject_get - increment refcount for object.
	322	* @kobj: object.
	323	*/
	324
	325	struct kobject * kobject_get(struct kobject * kobj)
	326	{
	327	if (kobj)
	328	kref_get(&kobj->kref);
	329	return kobj;
	330	}
	331
	332	/**
	333	* kobject_cleanup - free kobject resources.
	334	* @kobj: object.
	335	*/
	336
	337	void kobject_cleanup(struct kobject * kobj)
	338	{
	339	struct kobj_type * t = get_ktype(kobj);
	340	struct kset * s = kobj->kset;
	341	struct kobject * parent = kobj->parent;
	342
	343	pr_debug("kobject %s: cleaning up\n",kobject_name(kobj));
	344	if (kobj->k_name != kobj->name)
	345	kfree(kobj->k_name);
	346	kobj->k_name = NULL;
	347	if (t && t->release)
	348	t->release(kobj);
	349	if (s)
	350	kset_put(s);
	351	if (parent)
	352	kobject_put(parent);
	353	}
	354
	355	static void kobject_release(struct kref *kref)
	356	{
	357	kobject_cleanup(container_of(kref, struct kobject, kref));
	358	}
	359
	360	/**
	361	* kobject_put - decrement refcount for object.
	362	* @kobj: object.
	363	*
	364	* Decrement the refcount, and if 0, call kobject_cleanup().
	365	*/
	366	void kobject_put(struct kobject * kobj)
	367	{
	368	if (kobj)
	369	kref_put(&kobj->kref, kobject_release);
	370	}
	371
	372
	373	/**
	374	* kset_init - initialize a kset for use
	375	* @k: kset
	376	*/
	377
	378	void kset_init(struct kset * k)
	379	{
380	kobject_init(&k->kobj);
381	INIT_LIST_HEAD(&k->list);
382	spin_lock_init(&k->list_lock);
383	}
384
385
386	/**
387	* kset_add - add a kset object to the hierarchy.
388	* @k: kset.
389	*
390	* Simply, this adds the kset's embedded kobject to the
391	* hierarchy.
392	* We also try to make sure that the kset's embedded kobject
393	* has a parent before it is added. We only care if the embedded
394	* kobject is not part of a kset itself, since kobject_add()
395	* assigns a parent in that case.
396	* If that is the case, and the kset has a controlling subsystem,
397	* then we set the kset's parent to be said subsystem.
398	*/
399
400	int kset_add(struct kset * k)
401	{
402	if (!k->kobj.parent && !k->kobj.kset && k->subsys)
403	k->kobj.parent = &k->subsys->kset.kobj;
404
405	return kobject_add(&k->kobj);
406	}
407
408
409	/**
410	* kset_register - initialize and add a kset.
411	* @k: kset.
412	*/
413
414	int kset_register(struct kset * k)
415	{
416	kset_init(k);
417	return kset_add(k);
418	}
419
420
421	/**
422	* kset_unregister - remove a kset.
423	* @k: kset.
424	*/
425
426	void kset_unregister(struct kset * k)
427	{
428	kobject_unregister(&k->kobj);
429	}
430
431
432	/**
433	* kset_find_obj - search for object in kset.
434	* @kset: kset we're looking in.
435	* @name: object's name.
436	*
437	* Lock kset via @kset->subsys, and iterate over @kset->list,
438	* looking for a matching kobject. If matching object is found
439	* take a reference and return the object.
440	*/
441
442	struct kobject * kset_find_obj(struct kset * kset, const char * name)
443	{
444	struct list_head * entry;
445	struct kobject * ret = NULL;
446
447	spin_lock(&kset->list_lock);
448	list_for_each(entry,&kset->list) {
449	struct kobject * k = to_kobj(entry);
450	if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
451	ret = kobject_get(k);
452	break;
453	}
454	}
455	spin_unlock(&kset->list_lock);
456	return ret;
457	}
458
459
460	void subsystem_init(struct subsystem * s)
461	{
462	init_rwsem(&s->rwsem);
463	kset_init(&s->kset);
464	}
465
466	/**
467	* subsystem_register - register a subsystem.
468	* @s: the subsystem we're registering.
469	*
470	* Once we register the subsystem, we want to make sure that
471	* the kset points back to this subsystem for correct usage of
472	* the rwsem.
473	*/
474
475	int subsystem_register(struct subsystem * s)
476	{
477	int error;
478
479	subsystem_init(s);
480	pr_debug("subsystem %s: registering\n",s->kset.kobj.name);
481
482	if (!(error = kset_add(&s->kset))) {
483	if (!s->kset.subsys)
484	s->kset.subsys = s;
485	}
486	return error;
487	}
488
489	void subsystem_unregister(struct subsystem * s)
490	{
491	pr_debug("subsystem %s: unregistering\n",s->kset.kobj.name);
492	kset_unregister(&s->kset);
493	}
494
495
496	/**
497	* subsystem_create_file - export sysfs attribute file.
498	* @s: subsystem.
499	* @a: subsystem attribute descriptor.
500	*/
501
502	int subsys_create_file(struct subsystem * s, struct subsys_attribute * a)
503	{
504	int error = 0;
505	if (subsys_get(s)) {
506	error = sysfs_create_file(&s->kset.kobj,&a->attr);
507	subsys_put(s);
508	}
509	return error;
510	}
511
512
513	/**
514	* subsystem_remove_file - remove sysfs attribute file.
515	* @s: subsystem.
516	* @a: attribute desciptor.
517	*/
518
519	void subsys_remove_file(struct subsystem * s, struct subsys_attribute * a)
520	{
521	if (subsys_get(s)) {
522	sysfs_remove_file(&s->kset.kobj,&a->attr);
523	subsys_put(s);
524	}
525	}
526
527	EXPORT_SYMBOL(kobject_init);
528	EXPORT_SYMBOL(kobject_register);
529	EXPORT_SYMBOL(kobject_unregister);
530	EXPORT_SYMBOL(kobject_get);
531	EXPORT_SYMBOL(kobject_put);
532	EXPORT_SYMBOL(kobject_add);
533	EXPORT_SYMBOL(kobject_del);
534
535	EXPORT_SYMBOL(kset_register);
536	EXPORT_SYMBOL(kset_unregister);
537	EXPORT_SYMBOL(kset_find_obj);
538
539	EXPORT_SYMBOL(subsystem_init);
540	EXPORT_SYMBOL(subsystem_register);
541	EXPORT_SYMBOL(subsystem_unregister);
542	EXPORT_SYMBOL(subsys_create_file);
543	EXPORT_SYMBOL(subsys_remove_file);