Root/lib/kobject.c

1/*
2 * kobject.c - library routines for handling generic kernel objects
3 *
4 * Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org>
5 * Copyright (c) 2006-2007 Greg Kroah-Hartman <greg@kroah.com>
6 * Copyright (c) 2006-2007 Novell Inc.
7 *
8 * This file is released under the GPLv2.
9 *
10 *
11 * Please see the file Documentation/kobject.txt for critical information
12 * about using the kobject interface.
13 */
14
15#include <linux/kobject.h>
16#include <linux/string.h>
17#include <linux/module.h>
18#include <linux/stat.h>
19#include <linux/slab.h>
20
21/*
22 * populate_dir - populate directory with attributes.
23 * @kobj: object we're working on.
24 *
25 * Most subsystems have a set of default attributes that are associated
26 * with an object that registers with them. This is a helper called during
27 * object registration that loops through the default attributes of the
28 * subsystem and creates attributes files for them in sysfs.
29 */
30static 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            error = sysfs_create_file(kobj, attr);
40            if (error)
41                break;
42        }
43    }
44    return error;
45}
46
47static 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            error = populate_dir(kobj);
54            if (error)
55                sysfs_remove_dir(kobj);
56        }
57    }
58    return error;
59}
60
61static int get_kobj_path_length(struct kobject *kobj)
62{
63    int length = 1;
64    struct kobject *parent = kobj;
65
66    /* walk up the ancestors until we hit the one pointing to the
67     * root.
68     * Add 1 to strlen for leading '/' of each level.
69     */
70    do {
71        if (kobject_name(parent) == NULL)
72            return 0;
73        length += strlen(kobject_name(parent)) + 1;
74        parent = parent->parent;
75    } while (parent);
76    return length;
77}
78
79static void fill_kobj_path(struct kobject *kobj, char *path, int length)
80{
81    struct kobject *parent;
82
83    --length;
84    for (parent = kobj; parent; parent = parent->parent) {
85        int cur = strlen(kobject_name(parent));
86        /* back up enough to print this name with '/' */
87        length -= cur;
88        strncpy(path + length, kobject_name(parent), cur);
89        *(path + --length) = '/';
90    }
91
92    pr_debug("kobject: '%s' (%p): %s: path = '%s'\n", kobject_name(kobj),
93         kobj, __func__, path);
94}
95
96/**
97 * kobject_get_path - generate and return the path associated with a given kobj and kset pair.
98 *
99 * @kobj: kobject in question, with which to build the path
100 * @gfp_mask: the allocation type used to allocate the path
101 *
102 * The result must be freed by the caller with kfree().
103 */
104char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
105{
106    char *path;
107    int len;
108
109    len = get_kobj_path_length(kobj);
110    if (len == 0)
111        return NULL;
112    path = kzalloc(len, gfp_mask);
113    if (!path)
114        return NULL;
115    fill_kobj_path(kobj, path, len);
116
117    return path;
118}
119EXPORT_SYMBOL_GPL(kobject_get_path);
120
121/* add the kobject to its kset's list */
122static void kobj_kset_join(struct kobject *kobj)
123{
124    if (!kobj->kset)
125        return;
126
127    kset_get(kobj->kset);
128    spin_lock(&kobj->kset->list_lock);
129    list_add_tail(&kobj->entry, &kobj->kset->list);
130    spin_unlock(&kobj->kset->list_lock);
131}
132
133/* remove the kobject from its kset's list */
134static void kobj_kset_leave(struct kobject *kobj)
135{
136    if (!kobj->kset)
137        return;
138
139    spin_lock(&kobj->kset->list_lock);
140    list_del_init(&kobj->entry);
141    spin_unlock(&kobj->kset->list_lock);
142    kset_put(kobj->kset);
143}
144
145static void kobject_init_internal(struct kobject *kobj)
146{
147    if (!kobj)
148        return;
149    kref_init(&kobj->kref);
150    INIT_LIST_HEAD(&kobj->entry);
151    kobj->state_in_sysfs = 0;
152    kobj->state_add_uevent_sent = 0;
153    kobj->state_remove_uevent_sent = 0;
154    kobj->state_initialized = 1;
155}
156
157
158static int kobject_add_internal(struct kobject *kobj)
159{
160    int error = 0;
161    struct kobject *parent;
162
163    if (!kobj)
164        return -ENOENT;
165
166    if (!kobj->name || !kobj->name[0]) {
167        WARN(1, "kobject: (%p): attempted to be registered with empty "
168             "name!\n", kobj);
169        return -EINVAL;
170    }
171
172    parent = kobject_get(kobj->parent);
173
174    /* join kset if set, use it as parent if we do not already have one */
175    if (kobj->kset) {
176        if (!parent)
177            parent = kobject_get(&kobj->kset->kobj);
178        kobj_kset_join(kobj);
179        kobj->parent = parent;
180    }
181
182    pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n",
183         kobject_name(kobj), kobj, __func__,
184         parent ? kobject_name(parent) : "<NULL>",
185         kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>");
186
187    error = create_dir(kobj);
188    if (error) {
189        kobj_kset_leave(kobj);
190        kobject_put(parent);
191        kobj->parent = NULL;
192
193        /* be noisy on error issues */
194        if (error == -EEXIST)
195            printk(KERN_ERR "%s failed for %s with "
196                   "-EEXIST, don't try to register things with "
197                   "the same name in the same directory.\n",
198                   __func__, kobject_name(kobj));
199        else
200            printk(KERN_ERR "%s failed for %s (%d)\n",
201                   __func__, kobject_name(kobj), error);
202        dump_stack();
203    } else
204        kobj->state_in_sysfs = 1;
205
206    return error;
207}
208
209/**
210 * kobject_set_name_vargs - Set the name of an kobject
211 * @kobj: struct kobject to set the name of
212 * @fmt: format string used to build the name
213 * @vargs: vargs to format the string.
214 */
215int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
216                  va_list vargs)
217{
218    const char *old_name = kobj->name;
219    char *s;
220
221    if (kobj->name && !fmt)
222        return 0;
223
224    kobj->name = kvasprintf(GFP_KERNEL, fmt, vargs);
225    if (!kobj->name)
226        return -ENOMEM;
227
228    /* ewww... some of these buggers have '/' in the name ... */
229    while ((s = strchr(kobj->name, '/')))
230        s[0] = '!';
231
232    kfree(old_name);
233    return 0;
234}
235
236/**
237 * kobject_set_name - Set the name of a kobject
238 * @kobj: struct kobject to set the name of
239 * @fmt: format string used to build the name
240 *
241 * This sets the name of the kobject. If you have already added the
242 * kobject to the system, you must call kobject_rename() in order to
243 * change the name of the kobject.
244 */
245int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
246{
247    va_list vargs;
248    int retval;
249
250    va_start(vargs, fmt);
251    retval = kobject_set_name_vargs(kobj, fmt, vargs);
252    va_end(vargs);
253
254    return retval;
255}
256EXPORT_SYMBOL(kobject_set_name);
257
258/**
259 * kobject_init - initialize a kobject structure
260 * @kobj: pointer to the kobject to initialize
261 * @ktype: pointer to the ktype for this kobject.
262 *
263 * This function will properly initialize a kobject such that it can then
264 * be passed to the kobject_add() call.
265 *
266 * After this function is called, the kobject MUST be cleaned up by a call
267 * to kobject_put(), not by a call to kfree directly to ensure that all of
268 * the memory is cleaned up properly.
269 */
270void kobject_init(struct kobject *kobj, struct kobj_type *ktype)
271{
272    char *err_str;
273
274    if (!kobj) {
275        err_str = "invalid kobject pointer!";
276        goto error;
277    }
278    if (!ktype) {
279        err_str = "must have a ktype to be initialized properly!\n";
280        goto error;
281    }
282    if (kobj->state_initialized) {
283        /* do not error out as sometimes we can recover */
284        printk(KERN_ERR "kobject (%p): tried to init an initialized "
285               "object, something is seriously wrong.\n", kobj);
286        dump_stack();
287    }
288
289    kobject_init_internal(kobj);
290    kobj->ktype = ktype;
291    return;
292
293error:
294    printk(KERN_ERR "kobject (%p): %s\n", kobj, err_str);
295    dump_stack();
296}
297EXPORT_SYMBOL(kobject_init);
298
299static int kobject_add_varg(struct kobject *kobj, struct kobject *parent,
300                const char *fmt, va_list vargs)
301{
302    int retval;
303
304    retval = kobject_set_name_vargs(kobj, fmt, vargs);
305    if (retval) {
306        printk(KERN_ERR "kobject: can not set name properly!\n");
307        return retval;
308    }
309    kobj->parent = parent;
310    return kobject_add_internal(kobj);
311}
312
313/**
314 * kobject_add - the main kobject add function
315 * @kobj: the kobject to add
316 * @parent: pointer to the parent of the kobject.
317 * @fmt: format to name the kobject with.
318 *
319 * The kobject name is set and added to the kobject hierarchy in this
320 * function.
321 *
322 * If @parent is set, then the parent of the @kobj will be set to it.
323 * If @parent is NULL, then the parent of the @kobj will be set to the
324 * kobject associted with the kset assigned to this kobject. If no kset
325 * is assigned to the kobject, then the kobject will be located in the
326 * root of the sysfs tree.
327 *
328 * If this function returns an error, kobject_put() must be called to
329 * properly clean up the memory associated with the object.
330 * Under no instance should the kobject that is passed to this function
331 * be directly freed with a call to kfree(), that can leak memory.
332 *
333 * Note, no "add" uevent will be created with this call, the caller should set
334 * up all of the necessary sysfs files for the object and then call
335 * kobject_uevent() with the UEVENT_ADD parameter to ensure that
336 * userspace is properly notified of this kobject's creation.
337 */
338int kobject_add(struct kobject *kobj, struct kobject *parent,
339        const char *fmt, ...)
340{
341    va_list args;
342    int retval;
343
344    if (!kobj)
345        return -EINVAL;
346
347    if (!kobj->state_initialized) {
348        printk(KERN_ERR "kobject '%s' (%p): tried to add an "
349               "uninitialized object, something is seriously wrong.\n",
350               kobject_name(kobj), kobj);
351        dump_stack();
352        return -EINVAL;
353    }
354    va_start(args, fmt);
355    retval = kobject_add_varg(kobj, parent, fmt, args);
356    va_end(args);
357
358    return retval;
359}
360EXPORT_SYMBOL(kobject_add);
361
362/**
363 * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
364 * @kobj: pointer to the kobject to initialize
365 * @ktype: pointer to the ktype for this kobject.
366 * @parent: pointer to the parent of this kobject.
367 * @fmt: the name of the kobject.
368 *
369 * This function combines the call to kobject_init() and
370 * kobject_add(). The same type of error handling after a call to
371 * kobject_add() and kobject lifetime rules are the same here.
372 */
373int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
374             struct kobject *parent, const char *fmt, ...)
375{
376    va_list args;
377    int retval;
378
379    kobject_init(kobj, ktype);
380
381    va_start(args, fmt);
382    retval = kobject_add_varg(kobj, parent, fmt, args);
383    va_end(args);
384
385    return retval;
386}
387EXPORT_SYMBOL_GPL(kobject_init_and_add);
388
389/**
390 * kobject_rename - change the name of an object
391 * @kobj: object in question.
392 * @new_name: object's new name
393 *
394 * It is the responsibility of the caller to provide mutual
395 * exclusion between two different calls of kobject_rename
396 * on the same kobject and to ensure that new_name is valid and
397 * won't conflict with other kobjects.
398 */
399int kobject_rename(struct kobject *kobj, const char *new_name)
400{
401    int error = 0;
402    const char *devpath = NULL;
403    const char *dup_name = NULL, *name;
404    char *devpath_string = NULL;
405    char *envp[2];
406
407    kobj = kobject_get(kobj);
408    if (!kobj)
409        return -EINVAL;
410    if (!kobj->parent)
411        return -EINVAL;
412
413    devpath = kobject_get_path(kobj, GFP_KERNEL);
414    if (!devpath) {
415        error = -ENOMEM;
416        goto out;
417    }
418    devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
419    if (!devpath_string) {
420        error = -ENOMEM;
421        goto out;
422    }
423    sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
424    envp[0] = devpath_string;
425    envp[1] = NULL;
426
427    name = dup_name = kstrdup(new_name, GFP_KERNEL);
428    if (!name) {
429        error = -ENOMEM;
430        goto out;
431    }
432
433    error = sysfs_rename_dir(kobj, new_name);
434    if (error)
435        goto out;
436
437    /* Install the new kobject name */
438    dup_name = kobj->name;
439    kobj->name = name;
440
441    /* This function is mostly/only used for network interface.
442     * Some hotplug package track interfaces by their name and
443     * therefore want to know when the name is changed by the user. */
444    kobject_uevent_env(kobj, KOBJ_MOVE, envp);
445
446out:
447    kfree(dup_name);
448    kfree(devpath_string);
449    kfree(devpath);
450    kobject_put(kobj);
451
452    return error;
453}
454EXPORT_SYMBOL_GPL(kobject_rename);
455
456/**
457 * kobject_move - move object to another parent
458 * @kobj: object in question.
459 * @new_parent: object's new parent (can be NULL)
460 */
461int kobject_move(struct kobject *kobj, struct kobject *new_parent)
462{
463    int error;
464    struct kobject *old_parent;
465    const char *devpath = NULL;
466    char *devpath_string = NULL;
467    char *envp[2];
468
469    kobj = kobject_get(kobj);
470    if (!kobj)
471        return -EINVAL;
472    new_parent = kobject_get(new_parent);
473    if (!new_parent) {
474        if (kobj->kset)
475            new_parent = kobject_get(&kobj->kset->kobj);
476    }
477    /* old object path */
478    devpath = kobject_get_path(kobj, GFP_KERNEL);
479    if (!devpath) {
480        error = -ENOMEM;
481        goto out;
482    }
483    devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
484    if (!devpath_string) {
485        error = -ENOMEM;
486        goto out;
487    }
488    sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
489    envp[0] = devpath_string;
490    envp[1] = NULL;
491    error = sysfs_move_dir(kobj, new_parent);
492    if (error)
493        goto out;
494    old_parent = kobj->parent;
495    kobj->parent = new_parent;
496    new_parent = NULL;
497    kobject_put(old_parent);
498    kobject_uevent_env(kobj, KOBJ_MOVE, envp);
499out:
500    kobject_put(new_parent);
501    kobject_put(kobj);
502    kfree(devpath_string);
503    kfree(devpath);
504    return error;
505}
506
507/**
508 * kobject_del - unlink kobject from hierarchy.
509 * @kobj: object.
510 */
511void kobject_del(struct kobject *kobj)
512{
513    if (!kobj)
514        return;
515
516    sysfs_remove_dir(kobj);
517    kobj->state_in_sysfs = 0;
518    kobj_kset_leave(kobj);
519    kobject_put(kobj->parent);
520    kobj->parent = NULL;
521}
522
523/**
524 * kobject_get - increment refcount for object.
525 * @kobj: object.
526 */
527struct kobject *kobject_get(struct kobject *kobj)
528{
529    if (kobj)
530        kref_get(&kobj->kref);
531    return kobj;
532}
533
534/*
535 * kobject_cleanup - free kobject resources.
536 * @kobj: object to cleanup
537 */
538static void kobject_cleanup(struct kobject *kobj)
539{
540    struct kobj_type *t = get_ktype(kobj);
541    const char *name = kobj->name;
542
543    pr_debug("kobject: '%s' (%p): %s\n",
544         kobject_name(kobj), kobj, __func__);
545
546    if (t && !t->release)
547        pr_debug("kobject: '%s' (%p): does not have a release() "
548             "function, it is broken and must be fixed.\n",
549             kobject_name(kobj), kobj);
550
551    /* send "remove" if the caller did not do it but sent "add" */
552    if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
553        pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n",
554             kobject_name(kobj), kobj);
555        kobject_uevent(kobj, KOBJ_REMOVE);
556    }
557
558    /* remove from sysfs if the caller did not do it */
559    if (kobj->state_in_sysfs) {
560        pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
561             kobject_name(kobj), kobj);
562        kobject_del(kobj);
563    }
564
565    if (t && t->release) {
566        pr_debug("kobject: '%s' (%p): calling ktype release\n",
567             kobject_name(kobj), kobj);
568        t->release(kobj);
569    }
570
571    /* free name if we allocated it */
572    if (name) {
573        pr_debug("kobject: '%s': free name\n", name);
574        kfree(name);
575    }
576}
577
578static void kobject_release(struct kref *kref)
579{
580    kobject_cleanup(container_of(kref, struct kobject, kref));
581}
582
583/**
584 * kobject_put - decrement refcount for object.
585 * @kobj: object.
586 *
587 * Decrement the refcount, and if 0, call kobject_cleanup().
588 */
589void kobject_put(struct kobject *kobj)
590{
591    if (kobj) {
592        if (!kobj->state_initialized)
593            WARN(1, KERN_WARNING "kobject: '%s' (%p): is not "
594                   "initialized, yet kobject_put() is being "
595                   "called.\n", kobject_name(kobj), kobj);
596        kref_put(&kobj->kref, kobject_release);
597    }
598}
599
600static void dynamic_kobj_release(struct kobject *kobj)
601{
602    pr_debug("kobject: (%p): %s\n", kobj, __func__);
603    kfree(kobj);
604}
605
606static struct kobj_type dynamic_kobj_ktype = {
607    .release = dynamic_kobj_release,
608    .sysfs_ops = &kobj_sysfs_ops,
609};
610
611/**
612 * kobject_create - create a struct kobject dynamically
613 *
614 * This function creates a kobject structure dynamically and sets it up
615 * to be a "dynamic" kobject with a default release function set up.
616 *
617 * If the kobject was not able to be created, NULL will be returned.
618 * The kobject structure returned from here must be cleaned up with a
619 * call to kobject_put() and not kfree(), as kobject_init() has
620 * already been called on this structure.
621 */
622struct kobject *kobject_create(void)
623{
624    struct kobject *kobj;
625
626    kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
627    if (!kobj)
628        return NULL;
629
630    kobject_init(kobj, &dynamic_kobj_ktype);
631    return kobj;
632}
633
634/**
635 * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
636 *
637 * @name: the name for the kset
638 * @parent: the parent kobject of this kobject, if any.
639 *
640 * This function creates a kobject structure dynamically and registers it
641 * with sysfs. When you are finished with this structure, call
642 * kobject_put() and the structure will be dynamically freed when
643 * it is no longer being used.
644 *
645 * If the kobject was not able to be created, NULL will be returned.
646 */
647struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
648{
649    struct kobject *kobj;
650    int retval;
651
652    kobj = kobject_create();
653    if (!kobj)
654        return NULL;
655
656    retval = kobject_add(kobj, parent, "%s", name);
657    if (retval) {
658        printk(KERN_WARNING "%s: kobject_add error: %d\n",
659               __func__, retval);
660        kobject_put(kobj);
661        kobj = NULL;
662    }
663    return kobj;
664}
665EXPORT_SYMBOL_GPL(kobject_create_and_add);
666
667/**
668 * kset_init - initialize a kset for use
669 * @k: kset
670 */
671void kset_init(struct kset *k)
672{
673    kobject_init_internal(&k->kobj);
674    INIT_LIST_HEAD(&k->list);
675    spin_lock_init(&k->list_lock);
676}
677
678/* default kobject attribute operations */
679static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
680                  char *buf)
681{
682    struct kobj_attribute *kattr;
683    ssize_t ret = -EIO;
684
685    kattr = container_of(attr, struct kobj_attribute, attr);
686    if (kattr->show)
687        ret = kattr->show(kobj, kattr, buf);
688    return ret;
689}
690
691static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
692                   const char *buf, size_t count)
693{
694    struct kobj_attribute *kattr;
695    ssize_t ret = -EIO;
696
697    kattr = container_of(attr, struct kobj_attribute, attr);
698    if (kattr->store)
699        ret = kattr->store(kobj, kattr, buf, count);
700    return ret;
701}
702
703const struct sysfs_ops kobj_sysfs_ops = {
704    .show = kobj_attr_show,
705    .store = kobj_attr_store,
706};
707
708/**
709 * kset_register - initialize and add a kset.
710 * @k: kset.
711 */
712int kset_register(struct kset *k)
713{
714    int err;
715
716    if (!k)
717        return -EINVAL;
718
719    kset_init(k);
720    err = kobject_add_internal(&k->kobj);
721    if (err)
722        return err;
723    kobject_uevent(&k->kobj, KOBJ_ADD);
724    return 0;
725}
726
727/**
728 * kset_unregister - remove a kset.
729 * @k: kset.
730 */
731void kset_unregister(struct kset *k)
732{
733    if (!k)
734        return;
735    kobject_put(&k->kobj);
736}
737
738/**
739 * kset_find_obj - search for object in kset.
740 * @kset: kset we're looking in.
741 * @name: object's name.
742 *
743 * Lock kset via @kset->subsys, and iterate over @kset->list,
744 * looking for a matching kobject. If matching object is found
745 * take a reference and return the object.
746 */
747struct kobject *kset_find_obj(struct kset *kset, const char *name)
748{
749    struct kobject *k;
750    struct kobject *ret = NULL;
751
752    spin_lock(&kset->list_lock);
753    list_for_each_entry(k, &kset->list, entry) {
754        if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
755            ret = kobject_get(k);
756            break;
757        }
758    }
759    spin_unlock(&kset->list_lock);
760    return ret;
761}
762
763static void kset_release(struct kobject *kobj)
764{
765    struct kset *kset = container_of(kobj, struct kset, kobj);
766    pr_debug("kobject: '%s' (%p): %s\n",
767         kobject_name(kobj), kobj, __func__);
768    kfree(kset);
769}
770
771static struct kobj_type kset_ktype = {
772    .sysfs_ops = &kobj_sysfs_ops,
773    .release = kset_release,
774};
775
776/**
777 * kset_create - create a struct kset dynamically
778 *
779 * @name: the name for the kset
780 * @uevent_ops: a struct kset_uevent_ops for the kset
781 * @parent_kobj: the parent kobject of this kset, if any.
782 *
783 * This function creates a kset structure dynamically. This structure can
784 * then be registered with the system and show up in sysfs with a call to
785 * kset_register(). When you are finished with this structure, if
786 * kset_register() has been called, call kset_unregister() and the
787 * structure will be dynamically freed when it is no longer being used.
788 *
789 * If the kset was not able to be created, NULL will be returned.
790 */
791static struct kset *kset_create(const char *name,
792                const struct kset_uevent_ops *uevent_ops,
793                struct kobject *parent_kobj)
794{
795    struct kset *kset;
796    int retval;
797
798    kset = kzalloc(sizeof(*kset), GFP_KERNEL);
799    if (!kset)
800        return NULL;
801    retval = kobject_set_name(&kset->kobj, name);
802    if (retval) {
803        kfree(kset);
804        return NULL;
805    }
806    kset->uevent_ops = uevent_ops;
807    kset->kobj.parent = parent_kobj;
808
809    /*
810     * The kobject of this kset will have a type of kset_ktype and belong to
811     * no kset itself. That way we can properly free it when it is
812     * finished being used.
813     */
814    kset->kobj.ktype = &kset_ktype;
815    kset->kobj.kset = NULL;
816
817    return kset;
818}
819
820/**
821 * kset_create_and_add - create a struct kset dynamically and add it to sysfs
822 *
823 * @name: the name for the kset
824 * @uevent_ops: a struct kset_uevent_ops for the kset
825 * @parent_kobj: the parent kobject of this kset, if any.
826 *
827 * This function creates a kset structure dynamically and registers it
828 * with sysfs. When you are finished with this structure, call
829 * kset_unregister() and the structure will be dynamically freed when it
830 * is no longer being used.
831 *
832 * If the kset was not able to be created, NULL will be returned.
833 */
834struct kset *kset_create_and_add(const char *name,
835                 const struct kset_uevent_ops *uevent_ops,
836                 struct kobject *parent_kobj)
837{
838    struct kset *kset;
839    int error;
840
841    kset = kset_create(name, uevent_ops, parent_kobj);
842    if (!kset)
843        return NULL;
844    error = kset_register(kset);
845    if (error) {
846        kfree(kset);
847        return NULL;
848    }
849    return kset;
850}
851EXPORT_SYMBOL_GPL(kset_create_and_add);
852
853
854static DEFINE_SPINLOCK(kobj_ns_type_lock);
855static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
856
857int kobj_ns_type_register(const struct kobj_ns_type_operations *ops)
858{
859    enum kobj_ns_type type = ops->type;
860    int error;
861
862    spin_lock(&kobj_ns_type_lock);
863
864    error = -EINVAL;
865    if (type >= KOBJ_NS_TYPES)
866        goto out;
867
868    error = -EINVAL;
869    if (type <= KOBJ_NS_TYPE_NONE)
870        goto out;
871
872    error = -EBUSY;
873    if (kobj_ns_ops_tbl[type])
874        goto out;
875
876    error = 0;
877    kobj_ns_ops_tbl[type] = ops;
878
879out:
880    spin_unlock(&kobj_ns_type_lock);
881    return error;
882}
883
884int kobj_ns_type_registered(enum kobj_ns_type type)
885{
886    int registered = 0;
887
888    spin_lock(&kobj_ns_type_lock);
889    if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES))
890        registered = kobj_ns_ops_tbl[type] != NULL;
891    spin_unlock(&kobj_ns_type_lock);
892
893    return registered;
894}
895
896const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent)
897{
898    const struct kobj_ns_type_operations *ops = NULL;
899
900    if (parent && parent->ktype->child_ns_type)
901        ops = parent->ktype->child_ns_type(parent);
902
903    return ops;
904}
905
906const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj)
907{
908    return kobj_child_ns_ops(kobj->parent);
909}
910
911
912const void *kobj_ns_current(enum kobj_ns_type type)
913{
914    const void *ns = NULL;
915
916    spin_lock(&kobj_ns_type_lock);
917    if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
918        kobj_ns_ops_tbl[type])
919        ns = kobj_ns_ops_tbl[type]->current_ns();
920    spin_unlock(&kobj_ns_type_lock);
921
922    return ns;
923}
924
925const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk)
926{
927    const void *ns = NULL;
928
929    spin_lock(&kobj_ns_type_lock);
930    if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
931        kobj_ns_ops_tbl[type])
932        ns = kobj_ns_ops_tbl[type]->netlink_ns(sk);
933    spin_unlock(&kobj_ns_type_lock);
934
935    return ns;
936}
937
938const void *kobj_ns_initial(enum kobj_ns_type type)
939{
940    const void *ns = NULL;
941
942    spin_lock(&kobj_ns_type_lock);
943    if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
944        kobj_ns_ops_tbl[type])
945        ns = kobj_ns_ops_tbl[type]->initial_ns();
946    spin_unlock(&kobj_ns_type_lock);
947
948    return ns;
949}
950
951/*
952 * kobj_ns_exit - invalidate a namespace tag
953 *
954 * @type: the namespace type (i.e. KOBJ_NS_TYPE_NET)
955 * @ns: the actual namespace being invalidated
956 *
957 * This is called when a tag is no longer valid. For instance,
958 * when a network namespace exits, it uses this helper to
959 * make sure no sb's sysfs_info points to the now-invalidated
960 * netns.
961 */
962void kobj_ns_exit(enum kobj_ns_type type, const void *ns)
963{
964    sysfs_exit_ns(type, ns);
965}
966
967
968EXPORT_SYMBOL(kobject_get);
969EXPORT_SYMBOL(kobject_put);
970EXPORT_SYMBOL(kobject_del);
971
972EXPORT_SYMBOL(kset_register);
973EXPORT_SYMBOL(kset_unregister);
974

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