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/export.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        error = sysfs_create_dir(kobj);
  51        if (!error) {
  52                error = populate_dir(kobj);
  53                if (error)
  54                        sysfs_remove_dir(kobj);
  55        }
  56        return error;
  57}
  58
  59static int get_kobj_path_length(struct kobject *kobj)
  60{
  61        int length = 1;
  62        struct kobject *parent = kobj;
  63
  64        /* walk up the ancestors until we hit the one pointing to the
  65         * root.
  66         * Add 1 to strlen for leading '/' of each level.
  67         */
  68        do {
  69                if (kobject_name(parent) == NULL)
  70                        return 0;
  71                length += strlen(kobject_name(parent)) + 1;
  72                parent = parent->parent;
  73        } while (parent);
  74        return length;
  75}
  76
  77static void fill_kobj_path(struct kobject *kobj, char *path, int length)
  78{
  79        struct kobject *parent;
  80
  81        --length;
  82        for (parent = kobj; parent; parent = parent->parent) {
  83                int cur = strlen(kobject_name(parent));
  84                /* back up enough to print this name with '/' */
  85                length -= cur;
  86                strncpy(path + length, kobject_name(parent), cur);
  87                *(path + --length) = '/';
  88        }
  89
  90        pr_debug("kobject: '%s' (%p): %s: path = '%s'\n", kobject_name(kobj),
  91                 kobj, __func__, path);
  92}
  93
  94/**
  95 * kobject_get_path - generate and return the path associated with a given kobj and kset pair.
  96 *
  97 * @kobj:       kobject in question, with which to build the path
  98 * @gfp_mask:   the allocation type used to allocate the path
  99 *
 100 * The result must be freed by the caller with kfree().
 101 */
 102char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
 103{
 104        char *path;
 105        int len;
 106
 107        len = get_kobj_path_length(kobj);
 108        if (len == 0)
 109                return NULL;
 110        path = kzalloc(len, gfp_mask);
 111        if (!path)
 112                return NULL;
 113        fill_kobj_path(kobj, path, len);
 114
 115        return path;
 116}
 117EXPORT_SYMBOL_GPL(kobject_get_path);
 118
 119/* add the kobject to its kset's list */
 120static void kobj_kset_join(struct kobject *kobj)
 121{
 122        if (!kobj->kset)
 123                return;
 124
 125        kset_get(kobj->kset);
 126        spin_lock(&kobj->kset->list_lock);
 127        list_add_tail(&kobj->entry, &kobj->kset->list);
 128        spin_unlock(&kobj->kset->list_lock);
 129}
 130
 131/* remove the kobject from its kset's list */
 132static void kobj_kset_leave(struct kobject *kobj)
 133{
 134        if (!kobj->kset)
 135                return;
 136
 137        spin_lock(&kobj->kset->list_lock);
 138        list_del_init(&kobj->entry);
 139        spin_unlock(&kobj->kset->list_lock);
 140        kset_put(kobj->kset);
 141}
 142
 143static void kobject_init_internal(struct kobject *kobj)
 144{
 145        if (!kobj)
 146                return;
 147        kref_init(&kobj->kref);
 148        INIT_LIST_HEAD(&kobj->entry);
 149        kobj->state_in_sysfs = 0;
 150        kobj->state_add_uevent_sent = 0;
 151        kobj->state_remove_uevent_sent = 0;
 152        kobj->state_initialized = 1;
 153}
 154
 155
 156static int kobject_add_internal(struct kobject *kobj)
 157{
 158        int error = 0;
 159        struct kobject *parent;
 160
 161        if (!kobj)
 162                return -ENOENT;
 163
 164        if (!kobj->name || !kobj->name[0]) {
 165                WARN(1, "kobject: (%p): attempted to be registered with empty "
 166                         "name!\n", kobj);
 167                return -EINVAL;
 168        }
 169
 170        parent = kobject_get(kobj->parent);
 171
 172        /* join kset if set, use it as parent if we do not already have one */
 173        if (kobj->kset) {
 174                if (!parent)
 175                        parent = kobject_get(&kobj->kset->kobj);
 176                kobj_kset_join(kobj);
 177                kobj->parent = parent;
 178        }
 179
 180        pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n",
 181                 kobject_name(kobj), kobj, __func__,
 182                 parent ? kobject_name(parent) : "<NULL>",
 183                 kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>");
 184
 185        error = create_dir(kobj);
 186        if (error) {
 187                kobj_kset_leave(kobj);
 188                kobject_put(parent);
 189                kobj->parent = NULL;
 190
 191                /* be noisy on error issues */
 192                if (error == -EEXIST)
 193                        WARN(1, "%s failed for %s with "
 194                             "-EEXIST, don't try to register things with "
 195                             "the same name in the same directory.\n",
 196                             __func__, kobject_name(kobj));
 197                else
 198                        WARN(1, "%s failed for %s (error: %d parent: %s)\n",
 199                             __func__, kobject_name(kobj), error,
 200                             parent ? kobject_name(parent) : "'none'");
 201        } else
 202                kobj->state_in_sysfs = 1;
 203
 204        return error;
 205}
 206
 207/**
 208 * kobject_set_name_vargs - Set the name of an kobject
 209 * @kobj: struct kobject to set the name of
 210 * @fmt: format string used to build the name
 211 * @vargs: vargs to format the string.
 212 */
 213int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
 214                                  va_list vargs)
 215{
 216        const char *old_name = kobj->name;
 217        char *s;
 218
 219        if (kobj->name && !fmt)
 220                return 0;
 221
 222        kobj->name = kvasprintf(GFP_KERNEL, fmt, vargs);
 223        if (!kobj->name)
 224                return -ENOMEM;
 225
 226        /* ewww... some of these buggers have '/' in the name ... */
 227        while ((s = strchr(kobj->name, '/')))
 228                s[0] = '!';
 229
 230        kfree(old_name);
 231        return 0;
 232}
 233
 234/**
 235 * kobject_set_name - Set the name of a kobject
 236 * @kobj: struct kobject to set the name of
 237 * @fmt: format string used to build the name
 238 *
 239 * This sets the name of the kobject.  If you have already added the
 240 * kobject to the system, you must call kobject_rename() in order to
 241 * change the name of the kobject.
 242 */
 243int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
 244{
 245        va_list vargs;
 246        int retval;
 247
 248        va_start(vargs, fmt);
 249        retval = kobject_set_name_vargs(kobj, fmt, vargs);
 250        va_end(vargs);
 251
 252        return retval;
 253}
 254EXPORT_SYMBOL(kobject_set_name);
 255
 256/**
 257 * kobject_init - initialize a kobject structure
 258 * @kobj: pointer to the kobject to initialize
 259 * @ktype: pointer to the ktype for this kobject.
 260 *
 261 * This function will properly initialize a kobject such that it can then
 262 * be passed to the kobject_add() call.
 263 *
 264 * After this function is called, the kobject MUST be cleaned up by a call
 265 * to kobject_put(), not by a call to kfree directly to ensure that all of
 266 * the memory is cleaned up properly.
 267 */
 268void kobject_init(struct kobject *kobj, struct kobj_type *ktype)
 269{
 270        char *err_str;
 271
 272        if (!kobj) {
 273                err_str = "invalid kobject pointer!";
 274                goto error;
 275        }
 276        if (!ktype) {
 277                err_str = "must have a ktype to be initialized properly!\n";
 278                goto error;
 279        }
 280        if (kobj->state_initialized) {
 281                /* do not error out as sometimes we can recover */
 282                printk(KERN_ERR "kobject (%p): tried to init an initialized "
 283                       "object, something is seriously wrong.\n", kobj);
 284                dump_stack();
 285        }
 286
 287        kobject_init_internal(kobj);
 288        kobj->ktype = ktype;
 289        return;
 290
 291error:
 292        printk(KERN_ERR "kobject (%p): %s\n", kobj, err_str);
 293        dump_stack();
 294}
 295EXPORT_SYMBOL(kobject_init);
 296
 297static int kobject_add_varg(struct kobject *kobj, struct kobject *parent,
 298                            const char *fmt, va_list vargs)
 299{
 300        int retval;
 301
 302        retval = kobject_set_name_vargs(kobj, fmt, vargs);
 303        if (retval) {
 304                printk(KERN_ERR "kobject: can not set name properly!\n");
 305                return retval;
 306        }
 307        kobj->parent = parent;
 308        return kobject_add_internal(kobj);
 309}
 310
 311/**
 312 * kobject_add - the main kobject add function
 313 * @kobj: the kobject to add
 314 * @parent: pointer to the parent of the kobject.
 315 * @fmt: format to name the kobject with.
 316 *
 317 * The kobject name is set and added to the kobject hierarchy in this
 318 * function.
 319 *
 320 * If @parent is set, then the parent of the @kobj will be set to it.
 321 * If @parent is NULL, then the parent of the @kobj will be set to the
 322 * kobject associted with the kset assigned to this kobject.  If no kset
 323 * is assigned to the kobject, then the kobject will be located in the
 324 * root of the sysfs tree.
 325 *
 326 * If this function returns an error, kobject_put() must be called to
 327 * properly clean up the memory associated with the object.
 328 * Under no instance should the kobject that is passed to this function
 329 * be directly freed with a call to kfree(), that can leak memory.
 330 *
 331 * Note, no "add" uevent will be created with this call, the caller should set
 332 * up all of the necessary sysfs files for the object and then call
 333 * kobject_uevent() with the UEVENT_ADD parameter to ensure that
 334 * userspace is properly notified of this kobject's creation.
 335 */
 336int kobject_add(struct kobject *kobj, struct kobject *parent,
 337                const char *fmt, ...)
 338{
 339        va_list args;
 340        int retval;
 341
 342        if (!kobj)
 343                return -EINVAL;
 344
 345        if (!kobj->state_initialized) {
 346                printk(KERN_ERR "kobject '%s' (%p): tried to add an "
 347                       "uninitialized object, something is seriously wrong.\n",
 348                       kobject_name(kobj), kobj);
 349                dump_stack();
 350                return -EINVAL;
 351        }
 352        va_start(args, fmt);
 353        retval = kobject_add_varg(kobj, parent, fmt, args);
 354        va_end(args);
 355
 356        return retval;
 357}
 358EXPORT_SYMBOL(kobject_add);
 359
 360/**
 361 * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
 362 * @kobj: pointer to the kobject to initialize
 363 * @ktype: pointer to the ktype for this kobject.
 364 * @parent: pointer to the parent of this kobject.
 365 * @fmt: the name of the kobject.
 366 *
 367 * This function combines the call to kobject_init() and
 368 * kobject_add().  The same type of error handling after a call to
 369 * kobject_add() and kobject lifetime rules are the same here.
 370 */
 371int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
 372                         struct kobject *parent, const char *fmt, ...)
 373{
 374        va_list args;
 375        int retval;
 376
 377        kobject_init(kobj, ktype);
 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_GPL(kobject_init_and_add);
 386
 387/**
 388 * kobject_rename - change the name of an object
 389 * @kobj: object in question.
 390 * @new_name: object's new name
 391 *
 392 * It is the responsibility of the caller to provide mutual
 393 * exclusion between two different calls of kobject_rename
 394 * on the same kobject and to ensure that new_name is valid and
 395 * won't conflict with other kobjects.
 396 */
 397int kobject_rename(struct kobject *kobj, const char *new_name)
 398{
 399        int error = 0;
 400        const char *devpath = NULL;
 401        const char *dup_name = NULL, *name;
 402        char *devpath_string = NULL;
 403        char *envp[2];
 404
 405        kobj = kobject_get(kobj);
 406        if (!kobj)
 407                return -EINVAL;
 408        if (!kobj->parent)
 409                return -EINVAL;
 410
 411        devpath = kobject_get_path(kobj, GFP_KERNEL);
 412        if (!devpath) {
 413                error = -ENOMEM;
 414                goto out;
 415        }
 416        devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
 417        if (!devpath_string) {
 418                error = -ENOMEM;
 419                goto out;
 420        }
 421        sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
 422        envp[0] = devpath_string;
 423        envp[1] = NULL;
 424
 425        name = dup_name = kstrdup(new_name, GFP_KERNEL);
 426        if (!name) {
 427                error = -ENOMEM;
 428                goto out;
 429        }
 430
 431        error = sysfs_rename_dir(kobj, new_name);
 432        if (error)
 433                goto out;
 434
 435        /* Install the new kobject name */
 436        dup_name = kobj->name;
 437        kobj->name = name;
 438
 439        /* This function is mostly/only used for network interface.
 440         * Some hotplug package track interfaces by their name and
 441         * therefore want to know when the name is changed by the user. */
 442        kobject_uevent_env(kobj, KOBJ_MOVE, envp);
 443
 444out:
 445        kfree(dup_name);
 446        kfree(devpath_string);
 447        kfree(devpath);
 448        kobject_put(kobj);
 449
 450        return error;
 451}
 452EXPORT_SYMBOL_GPL(kobject_rename);
 453
 454/**
 455 * kobject_move - move object to another parent
 456 * @kobj: object in question.
 457 * @new_parent: object's new parent (can be NULL)
 458 */
 459int kobject_move(struct kobject *kobj, struct kobject *new_parent)
 460{
 461        int error;
 462        struct kobject *old_parent;
 463        const char *devpath = NULL;
 464        char *devpath_string = NULL;
 465        char *envp[2];
 466
 467        kobj = kobject_get(kobj);
 468        if (!kobj)
 469                return -EINVAL;
 470        new_parent = kobject_get(new_parent);
 471        if (!new_parent) {
 472                if (kobj->kset)
 473                        new_parent = kobject_get(&kobj->kset->kobj);
 474        }
 475        /* old object path */
 476        devpath = kobject_get_path(kobj, GFP_KERNEL);
 477        if (!devpath) {
 478                error = -ENOMEM;
 479                goto out;
 480        }
 481        devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
 482        if (!devpath_string) {
 483                error = -ENOMEM;
 484                goto out;
 485        }
 486        sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
 487        envp[0] = devpath_string;
 488        envp[1] = NULL;
 489        error = sysfs_move_dir(kobj, new_parent);
 490        if (error)
 491                goto out;
 492        old_parent = kobj->parent;
 493        kobj->parent = new_parent;
 494        new_parent = NULL;
 495        kobject_put(old_parent);
 496        kobject_uevent_env(kobj, KOBJ_MOVE, envp);
 497out:
 498        kobject_put(new_parent);
 499        kobject_put(kobj);
 500        kfree(devpath_string);
 501        kfree(devpath);
 502        return error;
 503}
 504
 505/**
 506 * kobject_del - unlink kobject from hierarchy.
 507 * @kobj: object.
 508 */
 509void kobject_del(struct kobject *kobj)
 510{
 511        if (!kobj)
 512                return;
 513
 514        sysfs_remove_dir(kobj);
 515        kobj->state_in_sysfs = 0;
 516        kobj_kset_leave(kobj);
 517        kobject_put(kobj->parent);
 518        kobj->parent = NULL;
 519}
 520
 521/**
 522 * kobject_get - increment refcount for object.
 523 * @kobj: object.
 524 */
 525struct kobject *kobject_get(struct kobject *kobj)
 526{
 527        if (kobj)
 528                kref_get(&kobj->kref);
 529        return kobj;
 530}
 531
 532/*
 533 * kobject_cleanup - free kobject resources.
 534 * @kobj: object to cleanup
 535 */
 536static void kobject_cleanup(struct kobject *kobj)
 537{
 538        struct kobj_type *t = get_ktype(kobj);
 539        const char *name = kobj->name;
 540
 541        pr_debug("kobject: '%s' (%p): %s\n",
 542                 kobject_name(kobj), kobj, __func__);
 543
 544        if (t && !t->release)
 545                pr_debug("kobject: '%s' (%p): does not have a release() "
 546                         "function, it is broken and must be fixed.\n",
 547                         kobject_name(kobj), kobj);
 548
 549        /* send "remove" if the caller did not do it but sent "add" */
 550        if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
 551                pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n",
 552                         kobject_name(kobj), kobj);
 553                kobject_uevent(kobj, KOBJ_REMOVE);
 554        }
 555
 556        /* remove from sysfs if the caller did not do it */
 557        if (kobj->state_in_sysfs) {
 558                pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
 559                         kobject_name(kobj), kobj);
 560                kobject_del(kobj);
 561        }
 562
 563        if (t && t->release) {
 564                pr_debug("kobject: '%s' (%p): calling ktype release\n",
 565                         kobject_name(kobj), kobj);
 566                t->release(kobj);
 567        }
 568
 569        /* free name if we allocated it */
 570        if (name) {
 571                pr_debug("kobject: '%s': free name\n", name);
 572                kfree(name);
 573        }
 574}
 575
 576static void kobject_release(struct kref *kref)
 577{
 578        kobject_cleanup(container_of(kref, struct kobject, kref));
 579}
 580
 581/**
 582 * kobject_put - decrement refcount for object.
 583 * @kobj: object.
 584 *
 585 * Decrement the refcount, and if 0, call kobject_cleanup().
 586 */
 587void kobject_put(struct kobject *kobj)
 588{
 589        if (kobj) {
 590                if (!kobj->state_initialized)
 591                        WARN(1, KERN_WARNING "kobject: '%s' (%p): is not "
 592                               "initialized, yet kobject_put() is being "
 593                               "called.\n", kobject_name(kobj), kobj);
 594                kref_put(&kobj->kref, kobject_release);
 595        }
 596}
 597
 598static void dynamic_kobj_release(struct kobject *kobj)
 599{
 600        pr_debug("kobject: (%p): %s\n", kobj, __func__);
 601        kfree(kobj);
 602}
 603
 604static struct kobj_type dynamic_kobj_ktype = {
 605        .release        = dynamic_kobj_release,
 606        .sysfs_ops      = &kobj_sysfs_ops,
 607};
 608
 609/**
 610 * kobject_create - create a struct kobject dynamically
 611 *
 612 * This function creates a kobject structure dynamically and sets it up
 613 * to be a "dynamic" kobject with a default release function set up.
 614 *
 615 * If the kobject was not able to be created, NULL will be returned.
 616 * The kobject structure returned from here must be cleaned up with a
 617 * call to kobject_put() and not kfree(), as kobject_init() has
 618 * already been called on this structure.
 619 */
 620struct kobject *kobject_create(void)
 621{
 622        struct kobject *kobj;
 623
 624        kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
 625        if (!kobj)
 626                return NULL;
 627
 628        kobject_init(kobj, &dynamic_kobj_ktype);
 629        return kobj;
 630}
 631
 632/**
 633 * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
 634 *
 635 * @name: the name for the kobject
 636 * @parent: the parent kobject of this kobject, if any.
 637 *
 638 * This function creates a kobject structure dynamically and registers it
 639 * with sysfs.  When you are finished with this structure, call
 640 * kobject_put() and the structure will be dynamically freed when
 641 * it is no longer being used.
 642 *
 643 * If the kobject was not able to be created, NULL will be returned.
 644 */
 645struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
 646{
 647        struct kobject *kobj;
 648        int retval;
 649
 650        kobj = kobject_create();
 651        if (!kobj)
 652                return NULL;
 653
 654        retval = kobject_add(kobj, parent, "%s", name);
 655        if (retval) {
 656                printk(KERN_WARNING "%s: kobject_add error: %d\n",
 657                       __func__, retval);
 658                kobject_put(kobj);
 659                kobj = NULL;
 660        }
 661        return kobj;
 662}
 663EXPORT_SYMBOL_GPL(kobject_create_and_add);
 664
 665/**
 666 * kset_init - initialize a kset for use
 667 * @k: kset
 668 */
 669void kset_init(struct kset *k)
 670{
 671        kobject_init_internal(&k->kobj);
 672        INIT_LIST_HEAD(&k->list);
 673        spin_lock_init(&k->list_lock);
 674}
 675
 676/* default kobject attribute operations */
 677static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
 678                              char *buf)
 679{
 680        struct kobj_attribute *kattr;
 681        ssize_t ret = -EIO;
 682
 683        kattr = container_of(attr, struct kobj_attribute, attr);
 684        if (kattr->show)
 685                ret = kattr->show(kobj, kattr, buf);
 686        return ret;
 687}
 688
 689static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
 690                               const char *buf, size_t count)
 691{
 692        struct kobj_attribute *kattr;
 693        ssize_t ret = -EIO;
 694
 695        kattr = container_of(attr, struct kobj_attribute, attr);
 696        if (kattr->store)
 697                ret = kattr->store(kobj, kattr, buf, count);
 698        return ret;
 699}
 700
 701const struct sysfs_ops kobj_sysfs_ops = {
 702        .show   = kobj_attr_show,
 703        .store  = kobj_attr_store,
 704};
 705
 706/**
 707 * kset_register - initialize and add a kset.
 708 * @k: kset.
 709 */
 710int kset_register(struct kset *k)
 711{
 712        int err;
 713
 714        if (!k)
 715                return -EINVAL;
 716
 717        kset_init(k);
 718        err = kobject_add_internal(&k->kobj);
 719        if (err)
 720                return err;
 721        kobject_uevent(&k->kobj, KOBJ_ADD);
 722        return 0;
 723}
 724
 725/**
 726 * kset_unregister - remove a kset.
 727 * @k: kset.
 728 */
 729void kset_unregister(struct kset *k)
 730{
 731        if (!k)
 732                return;
 733        kobject_put(&k->kobj);
 734}
 735
 736/**
 737 * kset_find_obj - search for object in kset.
 738 * @kset: kset we're looking in.
 739 * @name: object's name.
 740 *
 741 * Lock kset via @kset->subsys, and iterate over @kset->list,
 742 * looking for a matching kobject. If matching object is found
 743 * take a reference and return the object.
 744 */
 745struct kobject *kset_find_obj(struct kset *kset, const char *name)
 746{
 747        struct kobject *k;
 748        struct kobject *ret = NULL;
 749
 750        spin_lock(&kset->list_lock);
 751
 752        list_for_each_entry(k, &kset->list, entry) {
 753                if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
 754                        ret = kobject_get(k);
 755                        break;
 756                }
 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
 912void *kobj_ns_grab_current(enum kobj_ns_type type)
 913{
 914        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]->grab_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
 951void kobj_ns_drop(enum kobj_ns_type type, void *ns)
 952{
 953        spin_lock(&kobj_ns_type_lock);
 954        if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
 955            kobj_ns_ops_tbl[type] && kobj_ns_ops_tbl[type]->drop_ns)
 956                kobj_ns_ops_tbl[type]->drop_ns(ns);
 957        spin_unlock(&kobj_ns_type_lock);
 958}
 959
 960EXPORT_SYMBOL(kobject_get);
 961EXPORT_SYMBOL(kobject_put);
 962EXPORT_SYMBOL(kobject_del);
 963
 964EXPORT_SYMBOL(kset_register);
 965EXPORT_SYMBOL(kset_unregister);
 966
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