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/kobj_completion.h>
17#include <linux/string.h>
18#include <linux/export.h>
19#include <linux/stat.h>
20#include <linux/slab.h>
21
22/**
23 * kobject_namespace - return @kobj's namespace tag
24 * @kobj: kobject in question
25 *
26 * Returns namespace tag of @kobj if its parent has namespace ops enabled
27 * and thus @kobj should have a namespace tag associated with it. Returns
28 * %NULL otherwise.
29 */
30const void *kobject_namespace(struct kobject *kobj)
31{
32    const struct kobj_ns_type_operations *ns_ops = kobj_ns_ops(kobj);
33
34    if (!ns_ops || ns_ops->type == KOBJ_NS_TYPE_NONE)
35        return NULL;
36
37    return kobj->ktype->namespace(kobj);
38}
39
40/*
41 * populate_dir - populate directory with attributes.
42 * @kobj: object we're working on.
43 *
44 * Most subsystems have a set of default attributes that are associated
45 * with an object that registers with them. This is a helper called during
46 * object registration that loops through the default attributes of the
47 * subsystem and creates attributes files for them in sysfs.
48 */
49static int populate_dir(struct kobject *kobj)
50{
51    struct kobj_type *t = get_ktype(kobj);
52    struct attribute *attr;
53    int error = 0;
54    int i;
55
56    if (t && t->default_attrs) {
57        for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) {
58            error = sysfs_create_file(kobj, attr);
59            if (error)
60                break;
61        }
62    }
63    return error;
64}
65
66static int create_dir(struct kobject *kobj)
67{
68    int error;
69
70    error = sysfs_create_dir_ns(kobj, kobject_namespace(kobj));
71    if (!error) {
72        error = populate_dir(kobj);
73        if (error)
74            sysfs_remove_dir(kobj);
75    }
76
77    /*
78     * @kobj->sd may be deleted by an ancestor going away. Hold an
79     * extra reference so that it stays until @kobj is gone.
80     */
81    sysfs_get(kobj->sd);
82
83    return error;
84}
85
86static int get_kobj_path_length(struct kobject *kobj)
87{
88    int length = 1;
89    struct kobject *parent = kobj;
90
91    /* walk up the ancestors until we hit the one pointing to the
92     * root.
93     * Add 1 to strlen for leading '/' of each level.
94     */
95    do {
96        if (kobject_name(parent) == NULL)
97            return 0;
98        length += strlen(kobject_name(parent)) + 1;
99        parent = parent->parent;
100    } while (parent);
101    return length;
102}
103
104static void fill_kobj_path(struct kobject *kobj, char *path, int length)
105{
106    struct kobject *parent;
107
108    --length;
109    for (parent = kobj; parent; parent = parent->parent) {
110        int cur = strlen(kobject_name(parent));
111        /* back up enough to print this name with '/' */
112        length -= cur;
113        strncpy(path + length, kobject_name(parent), cur);
114        *(path + --length) = '/';
115    }
116
117    pr_debug("kobject: '%s' (%p): %s: path = '%s'\n", kobject_name(kobj),
118         kobj, __func__, path);
119}
120
121/**
122 * kobject_get_path - generate and return the path associated with a given kobj and kset pair.
123 *
124 * @kobj: kobject in question, with which to build the path
125 * @gfp_mask: the allocation type used to allocate the path
126 *
127 * The result must be freed by the caller with kfree().
128 */
129char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
130{
131    char *path;
132    int len;
133
134    len = get_kobj_path_length(kobj);
135    if (len == 0)
136        return NULL;
137    path = kzalloc(len, gfp_mask);
138    if (!path)
139        return NULL;
140    fill_kobj_path(kobj, path, len);
141
142    return path;
143}
144EXPORT_SYMBOL_GPL(kobject_get_path);
145
146/* add the kobject to its kset's list */
147static void kobj_kset_join(struct kobject *kobj)
148{
149    if (!kobj->kset)
150        return;
151
152    kset_get(kobj->kset);
153    spin_lock(&kobj->kset->list_lock);
154    list_add_tail(&kobj->entry, &kobj->kset->list);
155    spin_unlock(&kobj->kset->list_lock);
156}
157
158/* remove the kobject from its kset's list */
159static void kobj_kset_leave(struct kobject *kobj)
160{
161    if (!kobj->kset)
162        return;
163
164    spin_lock(&kobj->kset->list_lock);
165    list_del_init(&kobj->entry);
166    spin_unlock(&kobj->kset->list_lock);
167    kset_put(kobj->kset);
168}
169
170static void kobject_init_internal(struct kobject *kobj)
171{
172    if (!kobj)
173        return;
174    kref_init(&kobj->kref);
175    INIT_LIST_HEAD(&kobj->entry);
176    kobj->state_in_sysfs = 0;
177    kobj->state_add_uevent_sent = 0;
178    kobj->state_remove_uevent_sent = 0;
179    kobj->state_initialized = 1;
180}
181
182
183static int kobject_add_internal(struct kobject *kobj)
184{
185    int error = 0;
186    struct kobject *parent;
187
188    if (!kobj)
189        return -ENOENT;
190
191    if (!kobj->name || !kobj->name[0]) {
192        WARN(1, "kobject: (%p): attempted to be registered with empty "
193             "name!\n", kobj);
194        return -EINVAL;
195    }
196
197    parent = kobject_get(kobj->parent);
198
199    /* join kset if set, use it as parent if we do not already have one */
200    if (kobj->kset) {
201        if (!parent)
202            parent = kobject_get(&kobj->kset->kobj);
203        kobj_kset_join(kobj);
204        kobj->parent = parent;
205    }
206
207    pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n",
208         kobject_name(kobj), kobj, __func__,
209         parent ? kobject_name(parent) : "<NULL>",
210         kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>");
211
212    error = create_dir(kobj);
213    if (error) {
214        kobj_kset_leave(kobj);
215        kobject_put(parent);
216        kobj->parent = NULL;
217
218        /* be noisy on error issues */
219        if (error == -EEXIST)
220            WARN(1, "%s failed for %s with "
221                 "-EEXIST, don't try to register things with "
222                 "the same name in the same directory.\n",
223                 __func__, kobject_name(kobj));
224        else
225            WARN(1, "%s failed for %s (error: %d parent: %s)\n",
226                 __func__, kobject_name(kobj), error,
227                 parent ? kobject_name(parent) : "'none'");
228    } else
229        kobj->state_in_sysfs = 1;
230
231    return error;
232}
233
234/**
235 * kobject_set_name_vargs - Set the name of an kobject
236 * @kobj: struct kobject to set the name of
237 * @fmt: format string used to build the name
238 * @vargs: vargs to format the string.
239 */
240int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
241                  va_list vargs)
242{
243    const char *old_name = kobj->name;
244    char *s;
245
246    if (kobj->name && !fmt)
247        return 0;
248
249    kobj->name = kvasprintf(GFP_KERNEL, fmt, vargs);
250    if (!kobj->name)
251        return -ENOMEM;
252
253    /* ewww... some of these buggers have '/' in the name ... */
254    while ((s = strchr(kobj->name, '/')))
255        s[0] = '!';
256
257    kfree(old_name);
258    return 0;
259}
260
261/**
262 * kobject_set_name - Set the name of a kobject
263 * @kobj: struct kobject to set the name of
264 * @fmt: format string used to build the name
265 *
266 * This sets the name of the kobject. If you have already added the
267 * kobject to the system, you must call kobject_rename() in order to
268 * change the name of the kobject.
269 */
270int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
271{
272    va_list vargs;
273    int retval;
274
275    va_start(vargs, fmt);
276    retval = kobject_set_name_vargs(kobj, fmt, vargs);
277    va_end(vargs);
278
279    return retval;
280}
281EXPORT_SYMBOL(kobject_set_name);
282
283/**
284 * kobject_init - initialize a kobject structure
285 * @kobj: pointer to the kobject to initialize
286 * @ktype: pointer to the ktype for this kobject.
287 *
288 * This function will properly initialize a kobject such that it can then
289 * be passed to the kobject_add() call.
290 *
291 * After this function is called, the kobject MUST be cleaned up by a call
292 * to kobject_put(), not by a call to kfree directly to ensure that all of
293 * the memory is cleaned up properly.
294 */
295void kobject_init(struct kobject *kobj, struct kobj_type *ktype)
296{
297    char *err_str;
298
299    if (!kobj) {
300        err_str = "invalid kobject pointer!";
301        goto error;
302    }
303    if (!ktype) {
304        err_str = "must have a ktype to be initialized properly!\n";
305        goto error;
306    }
307    if (kobj->state_initialized) {
308        /* do not error out as sometimes we can recover */
309        printk(KERN_ERR "kobject (%p): tried to init an initialized "
310               "object, something is seriously wrong.\n", kobj);
311        dump_stack();
312    }
313
314    kobject_init_internal(kobj);
315    kobj->ktype = ktype;
316    return;
317
318error:
319    printk(KERN_ERR "kobject (%p): %s\n", kobj, err_str);
320    dump_stack();
321}
322EXPORT_SYMBOL(kobject_init);
323
324static int kobject_add_varg(struct kobject *kobj, struct kobject *parent,
325                const char *fmt, va_list vargs)
326{
327    int retval;
328
329    retval = kobject_set_name_vargs(kobj, fmt, vargs);
330    if (retval) {
331        printk(KERN_ERR "kobject: can not set name properly!\n");
332        return retval;
333    }
334    kobj->parent = parent;
335    return kobject_add_internal(kobj);
336}
337
338/**
339 * kobject_add - the main kobject add function
340 * @kobj: the kobject to add
341 * @parent: pointer to the parent of the kobject.
342 * @fmt: format to name the kobject with.
343 *
344 * The kobject name is set and added to the kobject hierarchy in this
345 * function.
346 *
347 * If @parent is set, then the parent of the @kobj will be set to it.
348 * If @parent is NULL, then the parent of the @kobj will be set to the
349 * kobject associted with the kset assigned to this kobject. If no kset
350 * is assigned to the kobject, then the kobject will be located in the
351 * root of the sysfs tree.
352 *
353 * If this function returns an error, kobject_put() must be called to
354 * properly clean up the memory associated with the object.
355 * Under no instance should the kobject that is passed to this function
356 * be directly freed with a call to kfree(), that can leak memory.
357 *
358 * Note, no "add" uevent will be created with this call, the caller should set
359 * up all of the necessary sysfs files for the object and then call
360 * kobject_uevent() with the UEVENT_ADD parameter to ensure that
361 * userspace is properly notified of this kobject's creation.
362 */
363int kobject_add(struct kobject *kobj, struct kobject *parent,
364        const char *fmt, ...)
365{
366    va_list args;
367    int retval;
368
369    if (!kobj)
370        return -EINVAL;
371
372    if (!kobj->state_initialized) {
373        printk(KERN_ERR "kobject '%s' (%p): tried to add an "
374               "uninitialized object, something is seriously wrong.\n",
375               kobject_name(kobj), kobj);
376        dump_stack();
377        return -EINVAL;
378    }
379    va_start(args, fmt);
380    retval = kobject_add_varg(kobj, parent, fmt, args);
381    va_end(args);
382
383    return retval;
384}
385EXPORT_SYMBOL(kobject_add);
386
387/**
388 * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
389 * @kobj: pointer to the kobject to initialize
390 * @ktype: pointer to the ktype for this kobject.
391 * @parent: pointer to the parent of this kobject.
392 * @fmt: the name of the kobject.
393 *
394 * This function combines the call to kobject_init() and
395 * kobject_add(). The same type of error handling after a call to
396 * kobject_add() and kobject lifetime rules are the same here.
397 */
398int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
399             struct kobject *parent, const char *fmt, ...)
400{
401    va_list args;
402    int retval;
403
404    kobject_init(kobj, ktype);
405
406    va_start(args, fmt);
407    retval = kobject_add_varg(kobj, parent, fmt, args);
408    va_end(args);
409
410    return retval;
411}
412EXPORT_SYMBOL_GPL(kobject_init_and_add);
413
414/**
415 * kobject_rename - change the name of an object
416 * @kobj: object in question.
417 * @new_name: object's new name
418 *
419 * It is the responsibility of the caller to provide mutual
420 * exclusion between two different calls of kobject_rename
421 * on the same kobject and to ensure that new_name is valid and
422 * won't conflict with other kobjects.
423 */
424int kobject_rename(struct kobject *kobj, const char *new_name)
425{
426    int error = 0;
427    const char *devpath = NULL;
428    const char *dup_name = NULL, *name;
429    char *devpath_string = NULL;
430    char *envp[2];
431
432    kobj = kobject_get(kobj);
433    if (!kobj)
434        return -EINVAL;
435    if (!kobj->parent)
436        return -EINVAL;
437
438    devpath = kobject_get_path(kobj, GFP_KERNEL);
439    if (!devpath) {
440        error = -ENOMEM;
441        goto out;
442    }
443    devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
444    if (!devpath_string) {
445        error = -ENOMEM;
446        goto out;
447    }
448    sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
449    envp[0] = devpath_string;
450    envp[1] = NULL;
451
452    name = dup_name = kstrdup(new_name, GFP_KERNEL);
453    if (!name) {
454        error = -ENOMEM;
455        goto out;
456    }
457
458    error = sysfs_rename_dir_ns(kobj, new_name, kobject_namespace(kobj));
459    if (error)
460        goto out;
461
462    /* Install the new kobject name */
463    dup_name = kobj->name;
464    kobj->name = name;
465
466    /* This function is mostly/only used for network interface.
467     * Some hotplug package track interfaces by their name and
468     * therefore want to know when the name is changed by the user. */
469    kobject_uevent_env(kobj, KOBJ_MOVE, envp);
470
471out:
472    kfree(dup_name);
473    kfree(devpath_string);
474    kfree(devpath);
475    kobject_put(kobj);
476
477    return error;
478}
479EXPORT_SYMBOL_GPL(kobject_rename);
480
481/**
482 * kobject_move - move object to another parent
483 * @kobj: object in question.
484 * @new_parent: object's new parent (can be NULL)
485 */
486int kobject_move(struct kobject *kobj, struct kobject *new_parent)
487{
488    int error;
489    struct kobject *old_parent;
490    const char *devpath = NULL;
491    char *devpath_string = NULL;
492    char *envp[2];
493
494    kobj = kobject_get(kobj);
495    if (!kobj)
496        return -EINVAL;
497    new_parent = kobject_get(new_parent);
498    if (!new_parent) {
499        if (kobj->kset)
500            new_parent = kobject_get(&kobj->kset->kobj);
501    }
502
503    /* old object path */
504    devpath = kobject_get_path(kobj, GFP_KERNEL);
505    if (!devpath) {
506        error = -ENOMEM;
507        goto out;
508    }
509    devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
510    if (!devpath_string) {
511        error = -ENOMEM;
512        goto out;
513    }
514    sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
515    envp[0] = devpath_string;
516    envp[1] = NULL;
517    error = sysfs_move_dir_ns(kobj, new_parent, kobject_namespace(kobj));
518    if (error)
519        goto out;
520    old_parent = kobj->parent;
521    kobj->parent = new_parent;
522    new_parent = NULL;
523    kobject_put(old_parent);
524    kobject_uevent_env(kobj, KOBJ_MOVE, envp);
525out:
526    kobject_put(new_parent);
527    kobject_put(kobj);
528    kfree(devpath_string);
529    kfree(devpath);
530    return error;
531}
532
533/**
534 * kobject_del - unlink kobject from hierarchy.
535 * @kobj: object.
536 */
537void kobject_del(struct kobject *kobj)
538{
539    struct sysfs_dirent *sd;
540
541    if (!kobj)
542        return;
543
544    sd = kobj->sd;
545    sysfs_remove_dir(kobj);
546    sysfs_put(sd);
547
548    kobj->state_in_sysfs = 0;
549    kobj_kset_leave(kobj);
550    kobject_put(kobj->parent);
551    kobj->parent = NULL;
552}
553
554/**
555 * kobject_get - increment refcount for object.
556 * @kobj: object.
557 */
558struct kobject *kobject_get(struct kobject *kobj)
559{
560    if (kobj)
561        kref_get(&kobj->kref);
562    return kobj;
563}
564
565static struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj)
566{
567    if (!kref_get_unless_zero(&kobj->kref))
568        kobj = NULL;
569    return kobj;
570}
571
572/*
573 * kobject_cleanup - free kobject resources.
574 * @kobj: object to cleanup
575 */
576static void kobject_cleanup(struct kobject *kobj)
577{
578    struct kobj_type *t = get_ktype(kobj);
579    const char *name = kobj->name;
580
581    pr_debug("kobject: '%s' (%p): %s, parent %p\n",
582         kobject_name(kobj), kobj, __func__, kobj->parent);
583
584    if (t && !t->release)
585        pr_debug("kobject: '%s' (%p): does not have a release() "
586             "function, it is broken and must be fixed.\n",
587             kobject_name(kobj), kobj);
588
589    /* send "remove" if the caller did not do it but sent "add" */
590    if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
591        pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n",
592             kobject_name(kobj), kobj);
593        kobject_uevent(kobj, KOBJ_REMOVE);
594    }
595
596    /* remove from sysfs if the caller did not do it */
597    if (kobj->state_in_sysfs) {
598        pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
599             kobject_name(kobj), kobj);
600        kobject_del(kobj);
601    }
602
603    if (t && t->release) {
604        pr_debug("kobject: '%s' (%p): calling ktype release\n",
605             kobject_name(kobj), kobj);
606        t->release(kobj);
607    }
608
609    /* free name if we allocated it */
610    if (name) {
611        pr_debug("kobject: '%s': free name\n", name);
612        kfree(name);
613    }
614}
615
616#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
617static void kobject_delayed_cleanup(struct work_struct *work)
618{
619    kobject_cleanup(container_of(to_delayed_work(work),
620                     struct kobject, release));
621}
622#endif
623
624static void kobject_release(struct kref *kref)
625{
626    struct kobject *kobj = container_of(kref, struct kobject, kref);
627#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
628    pr_info("kobject: '%s' (%p): %s, parent %p (delayed)\n",
629         kobject_name(kobj), kobj, __func__, kobj->parent);
630    INIT_DELAYED_WORK(&kobj->release, kobject_delayed_cleanup);
631    schedule_delayed_work(&kobj->release, HZ);
632#else
633    kobject_cleanup(kobj);
634#endif
635}
636
637/**
638 * kobject_put - decrement refcount for object.
639 * @kobj: object.
640 *
641 * Decrement the refcount, and if 0, call kobject_cleanup().
642 */
643void kobject_put(struct kobject *kobj)
644{
645    if (kobj) {
646        if (!kobj->state_initialized)
647            WARN(1, KERN_WARNING "kobject: '%s' (%p): is not "
648                   "initialized, yet kobject_put() is being "
649                   "called.\n", kobject_name(kobj), kobj);
650        kref_put(&kobj->kref, kobject_release);
651    }
652}
653
654static void dynamic_kobj_release(struct kobject *kobj)
655{
656    pr_debug("kobject: (%p): %s\n", kobj, __func__);
657    kfree(kobj);
658}
659
660static struct kobj_type dynamic_kobj_ktype = {
661    .release = dynamic_kobj_release,
662    .sysfs_ops = &kobj_sysfs_ops,
663};
664
665/**
666 * kobject_create - create a struct kobject dynamically
667 *
668 * This function creates a kobject structure dynamically and sets it up
669 * to be a "dynamic" kobject with a default release function set up.
670 *
671 * If the kobject was not able to be created, NULL will be returned.
672 * The kobject structure returned from here must be cleaned up with a
673 * call to kobject_put() and not kfree(), as kobject_init() has
674 * already been called on this structure.
675 */
676struct kobject *kobject_create(void)
677{
678    struct kobject *kobj;
679
680    kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
681    if (!kobj)
682        return NULL;
683
684    kobject_init(kobj, &dynamic_kobj_ktype);
685    return kobj;
686}
687
688/**
689 * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
690 *
691 * @name: the name for the kobject
692 * @parent: the parent kobject of this kobject, if any.
693 *
694 * This function creates a kobject structure dynamically and registers it
695 * with sysfs. When you are finished with this structure, call
696 * kobject_put() and the structure will be dynamically freed when
697 * it is no longer being used.
698 *
699 * If the kobject was not able to be created, NULL will be returned.
700 */
701struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
702{
703    struct kobject *kobj;
704    int retval;
705
706    kobj = kobject_create();
707    if (!kobj)
708        return NULL;
709
710    retval = kobject_add(kobj, parent, "%s", name);
711    if (retval) {
712        printk(KERN_WARNING "%s: kobject_add error: %d\n",
713               __func__, retval);
714        kobject_put(kobj);
715        kobj = NULL;
716    }
717    return kobj;
718}
719EXPORT_SYMBOL_GPL(kobject_create_and_add);
720
721/**
722 * kset_init - initialize a kset for use
723 * @k: kset
724 */
725void kset_init(struct kset *k)
726{
727    kobject_init_internal(&k->kobj);
728    INIT_LIST_HEAD(&k->list);
729    spin_lock_init(&k->list_lock);
730}
731
732/* default kobject attribute operations */
733static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
734                  char *buf)
735{
736    struct kobj_attribute *kattr;
737    ssize_t ret = -EIO;
738
739    kattr = container_of(attr, struct kobj_attribute, attr);
740    if (kattr->show)
741        ret = kattr->show(kobj, kattr, buf);
742    return ret;
743}
744
745static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
746                   const char *buf, size_t count)
747{
748    struct kobj_attribute *kattr;
749    ssize_t ret = -EIO;
750
751    kattr = container_of(attr, struct kobj_attribute, attr);
752    if (kattr->store)
753        ret = kattr->store(kobj, kattr, buf, count);
754    return ret;
755}
756
757const struct sysfs_ops kobj_sysfs_ops = {
758    .show = kobj_attr_show,
759    .store = kobj_attr_store,
760};
761
762/**
763 * kobj_completion_init - initialize a kobj_completion object.
764 * @kc: kobj_completion
765 * @ktype: type of kobject to initialize
766 *
767 * kobj_completion structures can be embedded within structures with different
768 * lifetime rules. During the release of the enclosing object, we can
769 * wait on the release of the kobject so that we don't free it while it's
770 * still busy.
771 */
772void kobj_completion_init(struct kobj_completion *kc, struct kobj_type *ktype)
773{
774    init_completion(&kc->kc_unregister);
775    kobject_init(&kc->kc_kobj, ktype);
776}
777EXPORT_SYMBOL_GPL(kobj_completion_init);
778
779/**
780 * kobj_completion_release - release a kobj_completion object
781 * @kobj: kobject embedded in kobj_completion
782 *
783 * Used with kobject_release to notify waiters that the kobject has been
784 * released.
785 */
786void kobj_completion_release(struct kobject *kobj)
787{
788    struct kobj_completion *kc = kobj_to_kobj_completion(kobj);
789    complete(&kc->kc_unregister);
790}
791EXPORT_SYMBOL_GPL(kobj_completion_release);
792
793/**
794 * kobj_completion_del_and_wait - release the kobject and wait for it
795 * @kc: kobj_completion object to release
796 *
797 * Delete the kobject from sysfs and drop the reference count. Then wait
798 * until any other outstanding references are also dropped. This routine
799 * is only necessary once other references may have been taken on the
800 * kobject. Typically this happens when the kobject has been published
801 * to sysfs via kobject_add.
802 */
803void kobj_completion_del_and_wait(struct kobj_completion *kc)
804{
805    kobject_del(&kc->kc_kobj);
806    kobject_put(&kc->kc_kobj);
807    wait_for_completion(&kc->kc_unregister);
808}
809EXPORT_SYMBOL_GPL(kobj_completion_del_and_wait);
810
811/**
812 * kset_register - initialize and add a kset.
813 * @k: kset.
814 */
815int kset_register(struct kset *k)
816{
817    int err;
818
819    if (!k)
820        return -EINVAL;
821
822    kset_init(k);
823    err = kobject_add_internal(&k->kobj);
824    if (err)
825        return err;
826    kobject_uevent(&k->kobj, KOBJ_ADD);
827    return 0;
828}
829
830/**
831 * kset_unregister - remove a kset.
832 * @k: kset.
833 */
834void kset_unregister(struct kset *k)
835{
836    if (!k)
837        return;
838    kobject_put(&k->kobj);
839}
840
841/**
842 * kset_find_obj - search for object in kset.
843 * @kset: kset we're looking in.
844 * @name: object's name.
845 *
846 * Lock kset via @kset->subsys, and iterate over @kset->list,
847 * looking for a matching kobject. If matching object is found
848 * take a reference and return the object.
849 */
850struct kobject *kset_find_obj(struct kset *kset, const char *name)
851{
852    struct kobject *k;
853    struct kobject *ret = NULL;
854
855    spin_lock(&kset->list_lock);
856
857    list_for_each_entry(k, &kset->list, entry) {
858        if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
859            ret = kobject_get_unless_zero(k);
860            break;
861        }
862    }
863
864    spin_unlock(&kset->list_lock);
865    return ret;
866}
867
868static void kset_release(struct kobject *kobj)
869{
870    struct kset *kset = container_of(kobj, struct kset, kobj);
871    pr_debug("kobject: '%s' (%p): %s\n",
872         kobject_name(kobj), kobj, __func__);
873    kfree(kset);
874}
875
876static struct kobj_type kset_ktype = {
877    .sysfs_ops = &kobj_sysfs_ops,
878    .release = kset_release,
879};
880
881/**
882 * kset_create - create a struct kset dynamically
883 *
884 * @name: the name for the kset
885 * @uevent_ops: a struct kset_uevent_ops for the kset
886 * @parent_kobj: the parent kobject of this kset, if any.
887 *
888 * This function creates a kset structure dynamically. This structure can
889 * then be registered with the system and show up in sysfs with a call to
890 * kset_register(). When you are finished with this structure, if
891 * kset_register() has been called, call kset_unregister() and the
892 * structure will be dynamically freed when it is no longer being used.
893 *
894 * If the kset was not able to be created, NULL will be returned.
895 */
896static struct kset *kset_create(const char *name,
897                const struct kset_uevent_ops *uevent_ops,
898                struct kobject *parent_kobj)
899{
900    struct kset *kset;
901    int retval;
902
903    kset = kzalloc(sizeof(*kset), GFP_KERNEL);
904    if (!kset)
905        return NULL;
906    retval = kobject_set_name(&kset->kobj, "%s", name);
907    if (retval) {
908        kfree(kset);
909        return NULL;
910    }
911    kset->uevent_ops = uevent_ops;
912    kset->kobj.parent = parent_kobj;
913
914    /*
915     * The kobject of this kset will have a type of kset_ktype and belong to
916     * no kset itself. That way we can properly free it when it is
917     * finished being used.
918     */
919    kset->kobj.ktype = &kset_ktype;
920    kset->kobj.kset = NULL;
921
922    return kset;
923}
924
925/**
926 * kset_create_and_add - create a struct kset dynamically and add it to sysfs
927 *
928 * @name: the name for the kset
929 * @uevent_ops: a struct kset_uevent_ops for the kset
930 * @parent_kobj: the parent kobject of this kset, if any.
931 *
932 * This function creates a kset structure dynamically and registers it
933 * with sysfs. When you are finished with this structure, call
934 * kset_unregister() and the structure will be dynamically freed when it
935 * is no longer being used.
936 *
937 * If the kset was not able to be created, NULL will be returned.
938 */
939struct kset *kset_create_and_add(const char *name,
940                 const struct kset_uevent_ops *uevent_ops,
941                 struct kobject *parent_kobj)
942{
943    struct kset *kset;
944    int error;
945
946    kset = kset_create(name, uevent_ops, parent_kobj);
947    if (!kset)
948        return NULL;
949    error = kset_register(kset);
950    if (error) {
951        kfree(kset);
952        return NULL;
953    }
954    return kset;
955}
956EXPORT_SYMBOL_GPL(kset_create_and_add);
957
958
959static DEFINE_SPINLOCK(kobj_ns_type_lock);
960static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
961
962int kobj_ns_type_register(const struct kobj_ns_type_operations *ops)
963{
964    enum kobj_ns_type type = ops->type;
965    int error;
966
967    spin_lock(&kobj_ns_type_lock);
968
969    error = -EINVAL;
970    if (type >= KOBJ_NS_TYPES)
971        goto out;
972
973    error = -EINVAL;
974    if (type <= KOBJ_NS_TYPE_NONE)
975        goto out;
976
977    error = -EBUSY;
978    if (kobj_ns_ops_tbl[type])
979        goto out;
980
981    error = 0;
982    kobj_ns_ops_tbl[type] = ops;
983
984out:
985    spin_unlock(&kobj_ns_type_lock);
986    return error;
987}
988
989int kobj_ns_type_registered(enum kobj_ns_type type)
990{
991    int registered = 0;
992
993    spin_lock(&kobj_ns_type_lock);
994    if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES))
995        registered = kobj_ns_ops_tbl[type] != NULL;
996    spin_unlock(&kobj_ns_type_lock);
997
998    return registered;
999}
1000
1001const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent)
1002{
1003    const struct kobj_ns_type_operations *ops = NULL;
1004
1005    if (parent && parent->ktype->child_ns_type)
1006        ops = parent->ktype->child_ns_type(parent);
1007
1008    return ops;
1009}
1010
1011const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj)
1012{
1013    return kobj_child_ns_ops(kobj->parent);
1014}
1015
1016bool kobj_ns_current_may_mount(enum kobj_ns_type type)
1017{
1018    bool may_mount = true;
1019
1020    spin_lock(&kobj_ns_type_lock);
1021    if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1022        kobj_ns_ops_tbl[type])
1023        may_mount = kobj_ns_ops_tbl[type]->current_may_mount();
1024    spin_unlock(&kobj_ns_type_lock);
1025
1026    return may_mount;
1027}
1028
1029void *kobj_ns_grab_current(enum kobj_ns_type type)
1030{
1031    void *ns = NULL;
1032
1033    spin_lock(&kobj_ns_type_lock);
1034    if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1035        kobj_ns_ops_tbl[type])
1036        ns = kobj_ns_ops_tbl[type]->grab_current_ns();
1037    spin_unlock(&kobj_ns_type_lock);
1038
1039    return ns;
1040}
1041
1042const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk)
1043{
1044    const void *ns = NULL;
1045
1046    spin_lock(&kobj_ns_type_lock);
1047    if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1048        kobj_ns_ops_tbl[type])
1049        ns = kobj_ns_ops_tbl[type]->netlink_ns(sk);
1050    spin_unlock(&kobj_ns_type_lock);
1051
1052    return ns;
1053}
1054
1055const void *kobj_ns_initial(enum kobj_ns_type type)
1056{
1057    const void *ns = NULL;
1058
1059    spin_lock(&kobj_ns_type_lock);
1060    if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1061        kobj_ns_ops_tbl[type])
1062        ns = kobj_ns_ops_tbl[type]->initial_ns();
1063    spin_unlock(&kobj_ns_type_lock);
1064
1065    return ns;
1066}
1067
1068void kobj_ns_drop(enum kobj_ns_type type, void *ns)
1069{
1070    spin_lock(&kobj_ns_type_lock);
1071    if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
1072        kobj_ns_ops_tbl[type] && kobj_ns_ops_tbl[type]->drop_ns)
1073        kobj_ns_ops_tbl[type]->drop_ns(ns);
1074    spin_unlock(&kobj_ns_type_lock);
1075}
1076
1077EXPORT_SYMBOL(kobject_get);
1078EXPORT_SYMBOL(kobject_put);
1079EXPORT_SYMBOL(kobject_del);
1080
1081EXPORT_SYMBOL(kset_register);
1082EXPORT_SYMBOL(kset_unregister);
1083

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