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
 532static struct kobject *kobject_get_unless_zero(struct kobject *kobj)
 533{
 534        if (!kref_get_unless_zero(&kobj->kref))
 535                kobj = NULL;
 536        return kobj;
 537}
 538
 539/*
 540 * kobject_cleanup - free kobject resources.
 541 * @kobj: object to cleanup
 542 */
 543static void kobject_cleanup(struct kobject *kobj)
 544{
 545        struct kobj_type *t = get_ktype(kobj);
 546        const char *name = kobj->name;
 547
 548        pr_debug("kobject: '%s' (%p): %s\n",
 549                 kobject_name(kobj), kobj, __func__);
 550
 551        if (t && !t->release)
 552                pr_debug("kobject: '%s' (%p): does not have a release() "
 553                         "function, it is broken and must be fixed.\n",
 554                         kobject_name(kobj), kobj);
 555
 556        /* send "remove" if the caller did not do it but sent "add" */
 557        if (kobj->state_add_uevent_sent && !kobj->state_remove_uevent_sent) {
 558                pr_debug("kobject: '%s' (%p): auto cleanup 'remove' event\n",
 559                         kobject_name(kobj), kobj);
 560                kobject_uevent(kobj, KOBJ_REMOVE);
 561        }
 562
 563        /* remove from sysfs if the caller did not do it */
 564        if (kobj->state_in_sysfs) {
 565                pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
 566                         kobject_name(kobj), kobj);
 567                kobject_del(kobj);
 568        }
 569
 570        if (t && t->release) {
 571                pr_debug("kobject: '%s' (%p): calling ktype release\n",
 572                         kobject_name(kobj), kobj);
 573                t->release(kobj);
 574        }
 575
 576        /* free name if we allocated it */
 577        if (name) {
 578                pr_debug("kobject: '%s': free name\n", name);
 579                kfree(name);
 580        }
 581}
 582
 583static void kobject_release(struct kref *kref)
 584{
 585        kobject_cleanup(container_of(kref, struct kobject, kref));
 586}
 587
 588/**
 589 * kobject_put - decrement refcount for object.
 590 * @kobj: object.
 591 *
 592 * Decrement the refcount, and if 0, call kobject_cleanup().
 593 */
 594void kobject_put(struct kobject *kobj)
 595{
 596        if (kobj) {
 597                if (!kobj->state_initialized)
 598                        WARN(1, KERN_WARNING "kobject: '%s' (%p): is not "
 599                               "initialized, yet kobject_put() is being "
 600                               "called.\n", kobject_name(kobj), kobj);
 601                kref_put(&kobj->kref, kobject_release);
 602        }
 603}
 604
 605static void dynamic_kobj_release(struct kobject *kobj)
 606{
 607        pr_debug("kobject: (%p): %s\n", kobj, __func__);
 608        kfree(kobj);
 609}
 610
 611static struct kobj_type dynamic_kobj_ktype = {
 612        .release        = dynamic_kobj_release,
 613        .sysfs_ops      = &kobj_sysfs_ops,
 614};
 615
 616/**
 617 * kobject_create - create a struct kobject dynamically
 618 *
 619 * This function creates a kobject structure dynamically and sets it up
 620 * to be a "dynamic" kobject with a default release function set up.
 621 *
 622 * If the kobject was not able to be created, NULL will be returned.
 623 * The kobject structure returned from here must be cleaned up with a
 624 * call to kobject_put() and not kfree(), as kobject_init() has
 625 * already been called on this structure.
 626 */
 627struct kobject *kobject_create(void)
 628{
 629        struct kobject *kobj;
 630
 631        kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
 632        if (!kobj)
 633                return NULL;
 634
 635        kobject_init(kobj, &dynamic_kobj_ktype);
 636        return kobj;
 637}
 638
 639/**
 640 * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
 641 *
 642 * @name: the name for the kobject
 643 * @parent: the parent kobject of this kobject, if any.
 644 *
 645 * This function creates a kobject structure dynamically and registers it
 646 * with sysfs.  When you are finished with this structure, call
 647 * kobject_put() and the structure will be dynamically freed when
 648 * it is no longer being used.
 649 *
 650 * If the kobject was not able to be created, NULL will be returned.
 651 */
 652struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
 653{
 654        struct kobject *kobj;
 655        int retval;
 656
 657        kobj = kobject_create();
 658        if (!kobj)
 659                return NULL;
 660
 661        retval = kobject_add(kobj, parent, "%s", name);
 662        if (retval) {
 663                printk(KERN_WARNING "%s: kobject_add error: %d\n",
 664                       __func__, retval);
 665                kobject_put(kobj);
 666                kobj = NULL;
 667        }
 668        return kobj;
 669}
 670EXPORT_SYMBOL_GPL(kobject_create_and_add);
 671
 672/**
 673 * kset_init - initialize a kset for use
 674 * @k: kset
 675 */
 676void kset_init(struct kset *k)
 677{
 678        kobject_init_internal(&k->kobj);
 679        INIT_LIST_HEAD(&k->list);
 680        spin_lock_init(&k->list_lock);
 681}
 682
 683/* default kobject attribute operations */
 684static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
 685                              char *buf)
 686{
 687        struct kobj_attribute *kattr;
 688        ssize_t ret = -EIO;
 689
 690        kattr = container_of(attr, struct kobj_attribute, attr);
 691        if (kattr->show)
 692                ret = kattr->show(kobj, kattr, buf);
 693        return ret;
 694}
 695
 696static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
 697                               const char *buf, size_t count)
 698{
 699        struct kobj_attribute *kattr;
 700        ssize_t ret = -EIO;
 701
 702        kattr = container_of(attr, struct kobj_attribute, attr);
 703        if (kattr->store)
 704                ret = kattr->store(kobj, kattr, buf, count);
 705        return ret;
 706}
 707
 708const struct sysfs_ops kobj_sysfs_ops = {
 709        .show   = kobj_attr_show,
 710        .store  = kobj_attr_store,
 711};
 712
 713/**
 714 * kset_register - initialize and add a kset.
 715 * @k: kset.
 716 */
 717int kset_register(struct kset *k)
 718{
 719        int err;
 720
 721        if (!k)
 722                return -EINVAL;
 723
 724        kset_init(k);
 725        err = kobject_add_internal(&k->kobj);
 726        if (err)
 727                return err;
 728        kobject_uevent(&k->kobj, KOBJ_ADD);
 729        return 0;
 730}
 731
 732/**
 733 * kset_unregister - remove a kset.
 734 * @k: kset.
 735 */
 736void kset_unregister(struct kset *k)
 737{
 738        if (!k)
 739                return;
 740        kobject_put(&k->kobj);
 741}
 742
 743/**
 744 * kset_find_obj - search for object in kset.
 745 * @kset: kset we're looking in.
 746 * @name: object's name.
 747 *
 748 * Lock kset via @kset->subsys, and iterate over @kset->list,
 749 * looking for a matching kobject. If matching object is found
 750 * take a reference and return the object.
 751 */
 752struct kobject *kset_find_obj(struct kset *kset, const char *name)
 753{
 754        struct kobject *k;
 755        struct kobject *ret = NULL;
 756
 757        spin_lock(&kset->list_lock);
 758
 759        list_for_each_entry(k, &kset->list, entry) {
 760                if (kobject_name(k) && !strcmp(kobject_name(k), name)) {
 761                        ret = kobject_get_unless_zero(k);
 762                        break;
 763                }
 764        }
 765
 766        spin_unlock(&kset->list_lock);
 767        return ret;
 768}
 769
 770static void kset_release(struct kobject *kobj)
 771{
 772        struct kset *kset = container_of(kobj, struct kset, kobj);
 773        pr_debug("kobject: '%s' (%p): %s\n",
 774                 kobject_name(kobj), kobj, __func__);
 775        kfree(kset);
 776}
 777
 778static struct kobj_type kset_ktype = {
 779        .sysfs_ops      = &kobj_sysfs_ops,
 780        .release = kset_release,
 781};
 782
 783/**
 784 * kset_create - create a struct kset dynamically
 785 *
 786 * @name: the name for the kset
 787 * @uevent_ops: a struct kset_uevent_ops for the kset
 788 * @parent_kobj: the parent kobject of this kset, if any.
 789 *
 790 * This function creates a kset structure dynamically.  This structure can
 791 * then be registered with the system and show up in sysfs with a call to
 792 * kset_register().  When you are finished with this structure, if
 793 * kset_register() has been called, call kset_unregister() and the
 794 * structure will be dynamically freed when it is no longer being used.
 795 *
 796 * If the kset was not able to be created, NULL will be returned.
 797 */
 798static struct kset *kset_create(const char *name,
 799                                const struct kset_uevent_ops *uevent_ops,
 800                                struct kobject *parent_kobj)
 801{
 802        struct kset *kset;
 803        int retval;
 804
 805        kset = kzalloc(sizeof(*kset), GFP_KERNEL);
 806        if (!kset)
 807                return NULL;
 808        retval = kobject_set_name(&kset->kobj, name);
 809        if (retval) {
 810                kfree(kset);
 811                return NULL;
 812        }
 813        kset->uevent_ops = uevent_ops;
 814        kset->kobj.parent = parent_kobj;
 815
 816        /*
 817         * The kobject of this kset will have a type of kset_ktype and belong to
 818         * no kset itself.  That way we can properly free it when it is
 819         * finished being used.
 820         */
 821        kset->kobj.ktype = &kset_ktype;
 822        kset->kobj.kset = NULL;
 823
 824        return kset;
 825}
 826
 827/**
 828 * kset_create_and_add - create a struct kset dynamically and add it to sysfs
 829 *
 830 * @name: the name for the kset
 831 * @uevent_ops: a struct kset_uevent_ops for the kset
 832 * @parent_kobj: the parent kobject of this kset, if any.
 833 *
 834 * This function creates a kset structure dynamically and registers it
 835 * with sysfs.  When you are finished with this structure, call
 836 * kset_unregister() and the structure will be dynamically freed when it
 837 * is no longer being used.
 838 *
 839 * If the kset was not able to be created, NULL will be returned.
 840 */
 841struct kset *kset_create_and_add(const char *name,
 842                                 const struct kset_uevent_ops *uevent_ops,
 843                                 struct kobject *parent_kobj)
 844{
 845        struct kset *kset;
 846        int error;
 847
 848        kset = kset_create(name, uevent_ops, parent_kobj);
 849        if (!kset)
 850                return NULL;
 851        error = kset_register(kset);
 852        if (error) {
 853                kfree(kset);
 854                return NULL;
 855        }
 856        return kset;
 857}
 858EXPORT_SYMBOL_GPL(kset_create_and_add);
 859
 860
 861static DEFINE_SPINLOCK(kobj_ns_type_lock);
 862static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
 863
 864int kobj_ns_type_register(const struct kobj_ns_type_operations *ops)
 865{
 866        enum kobj_ns_type type = ops->type;
 867        int error;
 868
 869        spin_lock(&kobj_ns_type_lock);
 870
 871        error = -EINVAL;
 872        if (type >= KOBJ_NS_TYPES)
 873                goto out;
 874
 875        error = -EINVAL;
 876        if (type <= KOBJ_NS_TYPE_NONE)
 877                goto out;
 878
 879        error = -EBUSY;
 880        if (kobj_ns_ops_tbl[type])
 881                goto out;
 882
 883        error = 0;
 884        kobj_ns_ops_tbl[type] = ops;
 885
 886out:
 887        spin_unlock(&kobj_ns_type_lock);
 888        return error;
 889}
 890
 891int kobj_ns_type_registered(enum kobj_ns_type type)
 892{
 893        int registered = 0;
 894
 895        spin_lock(&kobj_ns_type_lock);
 896        if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES))
 897                registered = kobj_ns_ops_tbl[type] != NULL;
 898        spin_unlock(&kobj_ns_type_lock);
 899
 900        return registered;
 901}
 902
 903const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent)
 904{
 905        const struct kobj_ns_type_operations *ops = NULL;
 906
 907        if (parent && parent->ktype->child_ns_type)
 908                ops = parent->ktype->child_ns_type(parent);
 909
 910        return ops;
 911}
 912
 913const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj)
 914{
 915        return kobj_child_ns_ops(kobj->parent);
 916}
 917
 918
 919void *kobj_ns_grab_current(enum kobj_ns_type type)
 920{
 921        void *ns = NULL;
 922
 923        spin_lock(&kobj_ns_type_lock);
 924        if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
 925            kobj_ns_ops_tbl[type])
 926                ns = kobj_ns_ops_tbl[type]->grab_current_ns();
 927        spin_unlock(&kobj_ns_type_lock);
 928
 929        return ns;
 930}
 931
 932const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk)
 933{
 934        const void *ns = NULL;
 935
 936        spin_lock(&kobj_ns_type_lock);
 937        if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
 938            kobj_ns_ops_tbl[type])
 939                ns = kobj_ns_ops_tbl[type]->netlink_ns(sk);
 940        spin_unlock(&kobj_ns_type_lock);
 941
 942        return ns;
 943}
 944
 945const void *kobj_ns_initial(enum kobj_ns_type type)
 946{
 947        const void *ns = NULL;
 948
 949        spin_lock(&kobj_ns_type_lock);
 950        if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
 951            kobj_ns_ops_tbl[type])
 952                ns = kobj_ns_ops_tbl[type]->initial_ns();
 953        spin_unlock(&kobj_ns_type_lock);
 954
 955        return ns;
 956}
 957
 958void kobj_ns_drop(enum kobj_ns_type type, void *ns)
 959{
 960        spin_lock(&kobj_ns_type_lock);
 961        if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
 962            kobj_ns_ops_tbl[type] && kobj_ns_ops_tbl[type]->drop_ns)
 963                kobj_ns_ops_tbl[type]->drop_ns(ns);
 964        spin_unlock(&kobj_ns_type_lock);
 965}
 966
 967EXPORT_SYMBOL(kobject_get);
 968EXPORT_SYMBOL(kobject_put);
 969EXPORT_SYMBOL(kobject_del);
 970
 971EXPORT_SYMBOL(kset_register);
 972EXPORT_SYMBOL(kset_unregister);
 973
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