kernel26-2.6.12-alx-r9/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>

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