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git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blob - lib/kobject.c
2 * kobject.c - library routines for handling generic kernel objects
4 * Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org>
6 * This file is released under the GPLv2.
9 * Please see the file Documentation/kobject.txt for critical information
10 * about using the kobject interface.
13 #include <linux/kobject.h>
14 #include <linux/string.h>
15 #include <linux/module.h>
16 #include <linux/stat.h>
17 #include <linux/slab.h>
20 * populate_dir - populate directory with attributes.
21 * @kobj: object we're working on.
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.
31 static int populate_dir(struct kobject
* kobj
)
33 struct kobj_type
* t
= get_ktype(kobj
);
34 struct attribute
* attr
;
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
)))
47 static int create_dir(struct kobject
* kobj
)
50 if (kobject_name(kobj
)) {
51 error
= sysfs_create_dir(kobj
);
53 if ((error
= populate_dir(kobj
)))
54 sysfs_remove_dir(kobj
);
60 static inline struct kobject
* to_kobj(struct list_head
* entry
)
62 return container_of(entry
,struct kobject
,entry
);
65 static int get_kobj_path_length(struct kobject
*kobj
)
68 struct kobject
* parent
= kobj
;
70 /* walk up the ancestors until we hit the one pointing to the
72 * Add 1 to strlen for leading '/' of each level.
75 if (kobject_name(parent
) == NULL
)
77 length
+= strlen(kobject_name(parent
)) + 1;
78 parent
= parent
->parent
;
83 static void fill_kobj_path(struct kobject
*kobj
, char *path
, int length
)
85 struct kobject
* parent
;
88 for (parent
= kobj
; parent
; parent
= parent
->parent
) {
89 int cur
= strlen(kobject_name(parent
));
90 /* back up enough to print this name with '/' */
92 strncpy (path
+ length
, kobject_name(parent
), cur
);
93 *(path
+ --length
) = '/';
96 pr_debug("%s: path = '%s'\n",__FUNCTION__
,path
);
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().
103 * @kobj: kobject in question, with which to build the path
104 * @gfp_mask: the allocation type used to allocate the path
106 char *kobject_get_path(struct kobject
*kobj
, gfp_t gfp_mask
)
111 len
= get_kobj_path_length(kobj
);
114 path
= kmalloc(len
, gfp_mask
);
117 memset(path
, 0x00, len
);
118 fill_kobj_path(kobj
, path
, len
);
124 * kobject_init - initialize object.
125 * @kobj: object in question.
127 void kobject_init(struct kobject
* kobj
)
129 kref_init(&kobj
->kref
);
130 INIT_LIST_HEAD(&kobj
->entry
);
131 kobj
->kset
= kset_get(kobj
->kset
);
136 * unlink - remove kobject from kset list.
139 * Remove the kobject from the kset list and decrement
140 * its parent's refcount.
141 * This is separated out, so we can use it in both
142 * kobject_del() and kobject_add() on error.
145 static void unlink(struct kobject
* kobj
)
148 spin_lock(&kobj
->kset
->list_lock
);
149 list_del_init(&kobj
->entry
);
150 spin_unlock(&kobj
->kset
->list_lock
);
156 * kobject_add - add an object to the hierarchy.
160 int kobject_add(struct kobject
* kobj
)
163 struct kobject
* parent
;
165 if (!(kobj
= kobject_get(kobj
)))
168 kobj
->k_name
= kobj
->name
;
170 pr_debug("kobject attempted to be registered with no name!\n");
174 parent
= kobject_get(kobj
->parent
);
176 pr_debug("kobject %s: registering. parent: %s, set: %s\n",
177 kobject_name(kobj
), parent
? kobject_name(parent
) : "<NULL>",
178 kobj
->kset
? kobj
->kset
->kobj
.name
: "<NULL>" );
181 spin_lock(&kobj
->kset
->list_lock
);
184 parent
= kobject_get(&kobj
->kset
->kobj
);
186 list_add_tail(&kobj
->entry
,&kobj
->kset
->list
);
187 spin_unlock(&kobj
->kset
->list_lock
);
189 kobj
->parent
= parent
;
191 error
= create_dir(kobj
);
193 /* unlink does the kobject_put() for us */
204 * kobject_register - initialize and add an object.
205 * @kobj: object in question.
208 int kobject_register(struct kobject
* kobj
)
213 error
= kobject_add(kobj
);
215 printk("kobject_register failed for %s (%d)\n",
216 kobject_name(kobj
),error
);
219 kobject_uevent(kobj
, KOBJ_ADD
);
227 * kobject_set_name - Set the name of an object
229 * @fmt: format string used to build the name
231 * If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated
232 * string that @kobj->k_name points to. Otherwise, use the static
235 int kobject_set_name(struct kobject
* kobj
, const char * fmt
, ...)
238 int limit
= KOBJ_NAME_LEN
;
244 * First, try the static array
247 need
= vsnprintf(kobj
->name
,limit
,fmt
,args
);
253 * Need more space? Allocate it and try again
256 name
= kmalloc(limit
,GFP_KERNEL
);
262 need
= vsnprintf(name
,limit
,fmt
,args
);
265 /* Still? Give up. */
273 /* Free the old name, if necessary. */
274 if (kobj
->k_name
&& kobj
->k_name
!= kobj
->name
)
277 /* Now, set the new name */
283 EXPORT_SYMBOL(kobject_set_name
);
287 * kobject_rename - change the name of an object
288 * @kobj: object in question.
289 * @new_name: object's new name
292 int kobject_rename(struct kobject
* kobj
, const char *new_name
)
296 kobj
= kobject_get(kobj
);
299 error
= sysfs_rename_dir(kobj
, new_name
);
306 * kobject_del - unlink kobject from hierarchy.
310 void kobject_del(struct kobject
* kobj
)
312 sysfs_remove_dir(kobj
);
317 * kobject_unregister - remove object from hierarchy and decrement refcount.
318 * @kobj: object going away.
321 void kobject_unregister(struct kobject
* kobj
)
323 pr_debug("kobject %s: unregistering\n",kobject_name(kobj
));
324 kobject_uevent(kobj
, KOBJ_REMOVE
);
330 * kobject_get - increment refcount for object.
334 struct kobject
* kobject_get(struct kobject
* kobj
)
337 kref_get(&kobj
->kref
);
342 * kobject_cleanup - free kobject resources.
346 void kobject_cleanup(struct kobject
* kobj
)
348 struct kobj_type
* t
= get_ktype(kobj
);
349 struct kset
* s
= kobj
->kset
;
350 struct kobject
* parent
= kobj
->parent
;
352 pr_debug("kobject %s: cleaning up\n",kobject_name(kobj
));
353 if (kobj
->k_name
!= kobj
->name
)
364 static void kobject_release(struct kref
*kref
)
366 kobject_cleanup(container_of(kref
, struct kobject
, kref
));
370 * kobject_put - decrement refcount for object.
373 * Decrement the refcount, and if 0, call kobject_cleanup().
375 void kobject_put(struct kobject
* kobj
)
378 kref_put(&kobj
->kref
, kobject_release
);
383 * kset_init - initialize a kset for use
387 void kset_init(struct kset
* k
)
389 kobject_init(&k
->kobj
);
390 INIT_LIST_HEAD(&k
->list
);
391 spin_lock_init(&k
->list_lock
);
396 * kset_add - add a kset object to the hierarchy.
399 * Simply, this adds the kset's embedded kobject to the
401 * We also try to make sure that the kset's embedded kobject
402 * has a parent before it is added. We only care if the embedded
403 * kobject is not part of a kset itself, since kobject_add()
404 * assigns a parent in that case.
405 * If that is the case, and the kset has a controlling subsystem,
406 * then we set the kset's parent to be said subsystem.
409 int kset_add(struct kset
* k
)
411 if (!k
->kobj
.parent
&& !k
->kobj
.kset
&& k
->subsys
)
412 k
->kobj
.parent
= &k
->subsys
->kset
.kobj
;
414 return kobject_add(&k
->kobj
);
419 * kset_register - initialize and add a kset.
423 int kset_register(struct kset
* k
)
431 * kset_unregister - remove a kset.
435 void kset_unregister(struct kset
* k
)
437 kobject_unregister(&k
->kobj
);
442 * kset_find_obj - search for object in kset.
443 * @kset: kset we're looking in.
444 * @name: object's name.
446 * Lock kset via @kset->subsys, and iterate over @kset->list,
447 * looking for a matching kobject. If matching object is found
448 * take a reference and return the object.
451 struct kobject
* kset_find_obj(struct kset
* kset
, const char * name
)
453 struct list_head
* entry
;
454 struct kobject
* ret
= NULL
;
456 spin_lock(&kset
->list_lock
);
457 list_for_each(entry
,&kset
->list
) {
458 struct kobject
* k
= to_kobj(entry
);
459 if (kobject_name(k
) && !strcmp(kobject_name(k
),name
)) {
460 ret
= kobject_get(k
);
464 spin_unlock(&kset
->list_lock
);
469 void subsystem_init(struct subsystem
* s
)
471 init_rwsem(&s
->rwsem
);
476 * subsystem_register - register a subsystem.
477 * @s: the subsystem we're registering.
479 * Once we register the subsystem, we want to make sure that
480 * the kset points back to this subsystem for correct usage of
484 int subsystem_register(struct subsystem
* s
)
489 pr_debug("subsystem %s: registering\n",s
->kset
.kobj
.name
);
491 if (!(error
= kset_add(&s
->kset
))) {
498 void subsystem_unregister(struct subsystem
* s
)
500 pr_debug("subsystem %s: unregistering\n",s
->kset
.kobj
.name
);
501 kset_unregister(&s
->kset
);
506 * subsystem_create_file - export sysfs attribute file.
508 * @a: subsystem attribute descriptor.
511 int subsys_create_file(struct subsystem
* s
, struct subsys_attribute
* a
)
515 error
= sysfs_create_file(&s
->kset
.kobj
,&a
->attr
);
523 * subsystem_remove_file - remove sysfs attribute file.
525 * @a: attribute desciptor.
528 void subsys_remove_file(struct subsystem
* s
, struct subsys_attribute
* a
)
531 sysfs_remove_file(&s
->kset
.kobj
,&a
->attr
);
536 EXPORT_SYMBOL(kobject_init
);
537 EXPORT_SYMBOL(kobject_register
);
538 EXPORT_SYMBOL(kobject_unregister
);
539 EXPORT_SYMBOL(kobject_get
);
540 EXPORT_SYMBOL(kobject_put
);
541 EXPORT_SYMBOL(kobject_add
);
542 EXPORT_SYMBOL(kobject_del
);
544 EXPORT_SYMBOL(kset_register
);
545 EXPORT_SYMBOL(kset_unregister
);
546 EXPORT_SYMBOL(kset_find_obj
);
548 EXPORT_SYMBOL(subsystem_init
);
549 EXPORT_SYMBOL(subsystem_register
);
550 EXPORT_SYMBOL(subsystem_unregister
);
551 EXPORT_SYMBOL(subsys_create_file
);
552 EXPORT_SYMBOL(subsys_remove_file
);