linux/lib/kobject.c
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   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        return kset_find_obj_hinted(kset, name, NULL);
 750}
 751
 752/**
 753 * kset_find_obj_hinted - search for object in kset given a predecessor hint.
 754 * @kset: kset we're looking in.
 755 * @name: object's name.
 756 * @hint: hint to possible object's predecessor.
 757 *
 758 * Check the hint's next object and if it is a match return it directly,
 759 * otherwise, fall back to the behavior of kset_find_obj().  Either way
 760 * a reference for the returned object is held and the reference on the
 761 * hinted object is released.
 762 */
 763struct kobject *kset_find_obj_hinted(struct kset *kset, const char *name,
 764                                     struct kobject *hint)
 765{
 766        struct kobject *k;
 767        struct kobject *ret = NULL;
 768
 769        spin_lock(&kset->list_lock);
 770
 771        if (!hint)
 772                goto slow_search;
 773
 774        /* end of list detection */
 775        if (hint->entry.next == kset->list.next)
 776                goto slow_search;
 777
 778        k = container_of(hint->entry.next, struct kobject, entry);
 779        if (!kobject_name(k) || strcmp(kobject_name(k), name))
 780                goto slow_search;
 781
 782        ret = kobject_get(k);
 783        goto unlock_exit;
 784
 785slow_search:
 786        list_for_each_entry(k, &kset->list, entry) {
 787                if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
 788                        ret = kobject_get(k);
 789                        break;
 790                }
 791        }
 792
 793unlock_exit:
 794        spin_unlock(&kset->list_lock);
 795
 796        if (hint)
 797                kobject_put(hint);
 798
 799        return ret;
 800}
 801
 802static void kset_release(struct kobject *kobj)
 803{
 804        struct kset *kset = container_of(kobj, struct kset, kobj);
 805        pr_debug("kobject: '%s' (%p): %s\n",
 806                 kobject_name(kobj), kobj, __func__);
 807        kfree(kset);
 808}
 809
 810static struct kobj_type kset_ktype = {
 811        .sysfs_ops      = &kobj_sysfs_ops,
 812        .release = kset_release,
 813};
 814
 815/**
 816 * kset_create - create a struct kset dynamically
 817 *
 818 * @name: the name for the kset
 819 * @uevent_ops: a struct kset_uevent_ops for the kset
 820 * @parent_kobj: the parent kobject of this kset, if any.
 821 *
 822 * This function creates a kset structure dynamically.  This structure can
 823 * then be registered with the system and show up in sysfs with a call to
 824 * kset_register().  When you are finished with this structure, if
 825 * kset_register() has been called, call kset_unregister() and the
 826 * structure will be dynamically freed when it is no longer being used.
 827 *
 828 * If the kset was not able to be created, NULL will be returned.
 829 */
 830static struct kset *kset_create(const char *name,
 831                                const struct kset_uevent_ops *uevent_ops,
 832                                struct kobject *parent_kobj)
 833{
 834        struct kset *kset;
 835        int retval;
 836
 837        kset = kzalloc(sizeof(*kset), GFP_KERNEL);
 838        if (!kset)
 839                return NULL;
 840        retval = kobject_set_name(&kset->kobj, name);
 841        if (retval) {
 842                kfree(kset);
 843                return NULL;
 844        }
 845        kset->uevent_ops = uevent_ops;
 846        kset->kobj.parent = parent_kobj;
 847
 848        /*
 849         * The kobject of this kset will have a type of kset_ktype and belong to
 850         * no kset itself.  That way we can properly free it when it is
 851         * finished being used.
 852         */
 853        kset->kobj.ktype = &kset_ktype;
 854        kset->kobj.kset = NULL;
 855
 856        return kset;
 857}
 858
 859/**
 860 * kset_create_and_add - create a struct kset dynamically and add it to sysfs
 861 *
 862 * @name: the name for the kset
 863 * @uevent_ops: a struct kset_uevent_ops for the kset
 864 * @parent_kobj: the parent kobject of this kset, if any.
 865 *
 866 * This function creates a kset structure dynamically and registers it
 867 * with sysfs.  When you are finished with this structure, call
 868 * kset_unregister() and the structure will be dynamically freed when it
 869 * is no longer being used.
 870 *
 871 * If the kset was not able to be created, NULL will be returned.
 872 */
 873struct kset *kset_create_and_add(const char *name,
 874                                 const struct kset_uevent_ops *uevent_ops,
 875                                 struct kobject *parent_kobj)
 876{
 877        struct kset *kset;
 878        int error;
 879
 880        kset = kset_create(name, uevent_ops, parent_kobj);
 881        if (!kset)
 882                return NULL;
 883        error = kset_register(kset);
 884        if (error) {
 885                kfree(kset);
 886                return NULL;
 887        }
 888        return kset;
 889}
 890EXPORT_SYMBOL_GPL(kset_create_and_add);
 891
 892
 893static DEFINE_SPINLOCK(kobj_ns_type_lock);
 894static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
 895
 896int kobj_ns_type_register(const struct kobj_ns_type_operations *ops)
 897{
 898        enum kobj_ns_type type = ops->type;
 899        int error;
 900
 901        spin_lock(&kobj_ns_type_lock);
 902
 903        error = -EINVAL;
 904        if (type >= KOBJ_NS_TYPES)
 905                goto out;
 906
 907        error = -EINVAL;
 908        if (type <= KOBJ_NS_TYPE_NONE)
 909                goto out;
 910
 911        error = -EBUSY;
 912        if (kobj_ns_ops_tbl[type])
 913                goto out;
 914
 915        error = 0;
 916        kobj_ns_ops_tbl[type] = ops;
 917
 918out:
 919        spin_unlock(&kobj_ns_type_lock);
 920        return error;
 921}
 922
 923int kobj_ns_type_registered(enum kobj_ns_type type)
 924{
 925        int registered = 0;
 926
 927        spin_lock(&kobj_ns_type_lock);
 928        if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES))
 929                registered = kobj_ns_ops_tbl[type] != NULL;
 930        spin_unlock(&kobj_ns_type_lock);
 931
 932        return registered;
 933}
 934
 935const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent)
 936{
 937        const struct kobj_ns_type_operations *ops = NULL;
 938
 939        if (parent && parent->ktype->child_ns_type)
 940                ops = parent->ktype->child_ns_type(parent);
 941
 942        return ops;
 943}
 944
 945const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj)
 946{
 947        return kobj_child_ns_ops(kobj->parent);
 948}
 949
 950
 951void *kobj_ns_grab_current(enum kobj_ns_type type)
 952{
 953        void *ns = NULL;
 954
 955        spin_lock(&kobj_ns_type_lock);
 956        if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
 957            kobj_ns_ops_tbl[type])
 958                ns = kobj_ns_ops_tbl[type]->grab_current_ns();
 959        spin_unlock(&kobj_ns_type_lock);
 960
 961        return ns;
 962}
 963
 964const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk)
 965{
 966        const void *ns = NULL;
 967
 968        spin_lock(&kobj_ns_type_lock);
 969        if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
 970            kobj_ns_ops_tbl[type])
 971                ns = kobj_ns_ops_tbl[type]->netlink_ns(sk);
 972        spin_unlock(&kobj_ns_type_lock);
 973
 974        return ns;
 975}
 976
 977const void *kobj_ns_initial(enum kobj_ns_type type)
 978{
 979        const void *ns = NULL;
 980
 981        spin_lock(&kobj_ns_type_lock);
 982        if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
 983            kobj_ns_ops_tbl[type])
 984                ns = kobj_ns_ops_tbl[type]->initial_ns();
 985        spin_unlock(&kobj_ns_type_lock);
 986
 987        return ns;
 988}
 989
 990void kobj_ns_drop(enum kobj_ns_type type, void *ns)
 991{
 992        spin_lock(&kobj_ns_type_lock);
 993        if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
 994            kobj_ns_ops_tbl[type] && kobj_ns_ops_tbl[type]->drop_ns)
 995                kobj_ns_ops_tbl[type]->drop_ns(ns);
 996        spin_unlock(&kobj_ns_type_lock);
 997}
 998
 999EXPORT_SYMBOL(kobject_get);
1000EXPORT_SYMBOL(kobject_put);
1001EXPORT_SYMBOL(kobject_del);
1002
1003EXPORT_SYMBOL(kset_register);
1004EXPORT_SYMBOL(kset_unregister);
1005
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