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git.proxmox.com Git - mirror_ubuntu-zesty-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
, struct dentry
*shadow_parent
)
50 if (kobject_name(kobj
)) {
51 error
= sysfs_create_dir(kobj
, shadow_parent
);
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 and kset pair.
102 * @kobj: kobject in question, with which to build the path
103 * @gfp_mask: the allocation type used to allocate the path
105 * The result must be freed by the caller with kfree().
107 char *kobject_get_path(struct kobject
*kobj
, gfp_t gfp_mask
)
112 len
= get_kobj_path_length(kobj
);
115 path
= kzalloc(len
, gfp_mask
);
118 fill_kobj_path(kobj
, path
, len
);
122 EXPORT_SYMBOL_GPL(kobject_get_path
);
125 * kobject_init - initialize object.
126 * @kobj: object in question.
128 void kobject_init(struct kobject
* kobj
)
132 kref_init(&kobj
->kref
);
133 INIT_LIST_HEAD(&kobj
->entry
);
134 init_waitqueue_head(&kobj
->poll
);
135 kobj
->kset
= kset_get(kobj
->kset
);
140 * unlink - remove kobject from kset list.
143 * Remove the kobject from the kset list and decrement
144 * its parent's refcount.
145 * This is separated out, so we can use it in both
146 * kobject_del() and kobject_add() on error.
149 static void unlink(struct kobject
* kobj
)
152 spin_lock(&kobj
->kset
->list_lock
);
153 list_del_init(&kobj
->entry
);
154 spin_unlock(&kobj
->kset
->list_lock
);
160 * kobject_add - add an object to the hierarchy.
162 * @shadow_parent: sysfs directory to add to.
165 int kobject_shadow_add(struct kobject
* kobj
, struct dentry
*shadow_parent
)
168 struct kobject
* parent
;
170 if (!(kobj
= kobject_get(kobj
)))
173 kobj
->k_name
= kobj
->name
;
174 if (!*kobj
->k_name
) {
175 pr_debug("kobject attempted to be registered with no name!\n");
179 parent
= kobject_get(kobj
->parent
);
181 pr_debug("kobject %s: registering. parent: %s, set: %s\n",
182 kobject_name(kobj
), parent
? kobject_name(parent
) : "<NULL>",
183 kobj
->kset
? kobj
->kset
->kobj
.name
: "<NULL>" );
186 spin_lock(&kobj
->kset
->list_lock
);
189 parent
= kobject_get(&kobj
->kset
->kobj
);
191 list_add_tail(&kobj
->entry
,&kobj
->kset
->list
);
192 spin_unlock(&kobj
->kset
->list_lock
);
194 kobj
->parent
= parent
;
196 error
= create_dir(kobj
, shadow_parent
);
198 /* unlink does the kobject_put() for us */
202 /* be noisy on error issues */
203 if (error
== -EEXIST
)
204 printk("kobject_add failed for %s with -EEXIST, "
205 "don't try to register things with the "
206 "same name in the same directory.\n",
209 printk("kobject_add failed for %s (%d)\n",
210 kobject_name(kobj
), error
);
218 * kobject_add - add an object to the hierarchy.
221 int kobject_add(struct kobject
* kobj
)
223 return kobject_shadow_add(kobj
, NULL
);
228 * kobject_register - initialize and add an object.
229 * @kobj: object in question.
232 int kobject_register(struct kobject
* kobj
)
237 error
= kobject_add(kobj
);
239 kobject_uevent(kobj
, KOBJ_ADD
);
246 * kobject_set_name - Set the name of an object
248 * @fmt: format string used to build the name
250 * If strlen(name) >= KOBJ_NAME_LEN, then use a dynamically allocated
251 * string that @kobj->k_name points to. Otherwise, use the static
254 int kobject_set_name(struct kobject
* kobj
, const char * fmt
, ...)
257 int limit
= KOBJ_NAME_LEN
;
263 * First, try the static array
266 need
= vsnprintf(kobj
->name
,limit
,fmt
,args
);
272 * Need more space? Allocate it and try again
275 name
= kmalloc(limit
,GFP_KERNEL
);
281 need
= vsnprintf(name
,limit
,fmt
,args
);
284 /* Still? Give up. */
292 /* Free the old name, if necessary. */
293 if (kobj
->k_name
&& kobj
->k_name
!= kobj
->name
)
296 /* Now, set the new name */
302 EXPORT_SYMBOL(kobject_set_name
);
306 * kobject_rename - change the name of an object
307 * @kobj: object in question.
308 * @new_name: object's new name
311 int kobject_rename(struct kobject
* kobj
, const char *new_name
)
315 kobj
= kobject_get(kobj
);
320 error
= sysfs_rename_dir(kobj
, kobj
->parent
->dentry
, new_name
);
327 * kobject_rename - change the name of an object
328 * @kobj: object in question.
329 * @new_parent: object's new parent
330 * @new_name: object's new name
333 int kobject_shadow_rename(struct kobject
* kobj
, struct dentry
*new_parent
,
334 const char *new_name
)
338 kobj
= kobject_get(kobj
);
341 error
= sysfs_rename_dir(kobj
, new_parent
, new_name
);
348 * kobject_move - move object to another parent
349 * @kobj: object in question.
350 * @new_parent: object's new parent (can be NULL)
353 int kobject_move(struct kobject
*kobj
, struct kobject
*new_parent
)
356 struct kobject
*old_parent
;
357 const char *devpath
= NULL
;
358 char *devpath_string
= NULL
;
361 kobj
= kobject_get(kobj
);
364 new_parent
= kobject_get(new_parent
);
367 new_parent
= kobject_get(&kobj
->kset
->kobj
);
369 /* old object path */
370 devpath
= kobject_get_path(kobj
, GFP_KERNEL
);
375 devpath_string
= kmalloc(strlen(devpath
) + 15, GFP_KERNEL
);
376 if (!devpath_string
) {
380 sprintf(devpath_string
, "DEVPATH_OLD=%s", devpath
);
381 envp
[0] = devpath_string
;
383 error
= sysfs_move_dir(kobj
, new_parent
);
386 old_parent
= kobj
->parent
;
387 kobj
->parent
= new_parent
;
389 kobject_put(old_parent
);
390 kobject_uevent_env(kobj
, KOBJ_MOVE
, envp
);
392 kobject_put(new_parent
);
394 kfree(devpath_string
);
400 * kobject_del - unlink kobject from hierarchy.
404 void kobject_del(struct kobject
* kobj
)
408 sysfs_remove_dir(kobj
);
413 * kobject_unregister - remove object from hierarchy and decrement refcount.
414 * @kobj: object going away.
417 void kobject_unregister(struct kobject
* kobj
)
421 pr_debug("kobject %s: unregistering\n",kobject_name(kobj
));
422 kobject_uevent(kobj
, KOBJ_REMOVE
);
428 * kobject_get - increment refcount for object.
432 struct kobject
* kobject_get(struct kobject
* kobj
)
435 kref_get(&kobj
->kref
);
440 * kobject_cleanup - free kobject resources.
444 void kobject_cleanup(struct kobject
* kobj
)
446 struct kobj_type
* t
= get_ktype(kobj
);
447 struct kset
* s
= kobj
->kset
;
448 struct kobject
* parent
= kobj
->parent
;
450 pr_debug("kobject %s: cleaning up\n",kobject_name(kobj
));
451 if (kobj
->k_name
!= kobj
->name
)
461 static void kobject_release(struct kref
*kref
)
463 kobject_cleanup(container_of(kref
, struct kobject
, kref
));
467 * kobject_put - decrement refcount for object.
470 * Decrement the refcount, and if 0, call kobject_cleanup().
472 void kobject_put(struct kobject
* kobj
)
475 kref_put(&kobj
->kref
, kobject_release
);
479 static void dir_release(struct kobject
*kobj
)
484 static struct kobj_type dir_ktype
= {
485 .release
= dir_release
,
487 .default_attrs
= NULL
,
491 * kobject__kset_add_dir - add sub directory of object.
492 * @kset: kset the directory is belongs to.
493 * @parent: object in which a directory is created.
494 * @name: directory name.
496 * Add a plain directory object as child of given object.
498 struct kobject
*kobject_kset_add_dir(struct kset
*kset
,
499 struct kobject
*parent
, const char *name
)
507 k
= kzalloc(sizeof(*k
), GFP_KERNEL
);
513 k
->ktype
= &dir_ktype
;
514 kobject_set_name(k
, name
);
515 ret
= kobject_register(k
);
517 printk(KERN_WARNING
"kobject_add_dir: "
518 "kobject_register error: %d\n", ret
);
526 struct kobject
*kobject_add_dir(struct kobject
*parent
, const char *name
)
528 return kobject_kset_add_dir(NULL
, parent
, name
);
532 * kset_init - initialize a kset for use
536 void kset_init(struct kset
* k
)
538 kobject_init(&k
->kobj
);
539 INIT_LIST_HEAD(&k
->list
);
540 spin_lock_init(&k
->list_lock
);
545 * kset_add - add a kset object to the hierarchy.
548 * Simply, this adds the kset's embedded kobject to the
550 * We also try to make sure that the kset's embedded kobject
551 * has a parent before it is added. We only care if the embedded
552 * kobject is not part of a kset itself, since kobject_add()
553 * assigns a parent in that case.
554 * If that is the case, and the kset has a controlling subsystem,
555 * then we set the kset's parent to be said subsystem.
558 int kset_add(struct kset
* k
)
560 if (!k
->kobj
.parent
&& !k
->kobj
.kset
&& k
->subsys
)
561 k
->kobj
.parent
= &k
->subsys
->kset
.kobj
;
563 return kobject_add(&k
->kobj
);
568 * kset_register - initialize and add a kset.
572 int kset_register(struct kset
* k
)
582 * kset_unregister - remove a kset.
586 void kset_unregister(struct kset
* k
)
590 kobject_unregister(&k
->kobj
);
595 * kset_find_obj - search for object in kset.
596 * @kset: kset we're looking in.
597 * @name: object's name.
599 * Lock kset via @kset->subsys, and iterate over @kset->list,
600 * looking for a matching kobject. If matching object is found
601 * take a reference and return the object.
604 struct kobject
* kset_find_obj(struct kset
* kset
, const char * name
)
606 struct list_head
* entry
;
607 struct kobject
* ret
= NULL
;
609 spin_lock(&kset
->list_lock
);
610 list_for_each(entry
,&kset
->list
) {
611 struct kobject
* k
= to_kobj(entry
);
612 if (kobject_name(k
) && !strcmp(kobject_name(k
),name
)) {
613 ret
= kobject_get(k
);
617 spin_unlock(&kset
->list_lock
);
622 void subsystem_init(struct subsystem
* s
)
624 init_rwsem(&s
->rwsem
);
629 * subsystem_register - register a subsystem.
630 * @s: the subsystem we're registering.
632 * Once we register the subsystem, we want to make sure that
633 * the kset points back to this subsystem for correct usage of
637 int subsystem_register(struct subsystem
* s
)
645 pr_debug("subsystem %s: registering\n",s
->kset
.kobj
.name
);
647 if (!(error
= kset_add(&s
->kset
))) {
654 void subsystem_unregister(struct subsystem
* s
)
658 pr_debug("subsystem %s: unregistering\n",s
->kset
.kobj
.name
);
659 kset_unregister(&s
->kset
);
664 * subsystem_create_file - export sysfs attribute file.
666 * @a: subsystem attribute descriptor.
669 int subsys_create_file(struct subsystem
* s
, struct subsys_attribute
* a
)
677 error
= sysfs_create_file(&s
->kset
.kobj
,&a
->attr
);
685 * subsystem_remove_file - remove sysfs attribute file.
687 * @a: attribute desciptor.
690 void subsys_remove_file(struct subsystem
* s
, struct subsys_attribute
* a
)
693 sysfs_remove_file(&s
->kset
.kobj
,&a
->attr
);
699 EXPORT_SYMBOL(kobject_init
);
700 EXPORT_SYMBOL(kobject_register
);
701 EXPORT_SYMBOL(kobject_unregister
);
702 EXPORT_SYMBOL(kobject_get
);
703 EXPORT_SYMBOL(kobject_put
);
704 EXPORT_SYMBOL(kobject_add
);
705 EXPORT_SYMBOL(kobject_del
);
707 EXPORT_SYMBOL(kset_register
);
708 EXPORT_SYMBOL(kset_unregister
);
710 EXPORT_SYMBOL(subsystem_register
);
711 EXPORT_SYMBOL(subsystem_unregister
);
712 EXPORT_SYMBOL(subsys_create_file
);