lib/kobject.c

   1 /*
   2  * kobject.c - library routines for handling generic kernel objects
   3  *
   4  * Copyright (c) 2002-2003 Patrick Mochel <mochel@osdl.org>
   5  * Copyright (c) 2006-2007 Greg Kroah-Hartman <greg@kroah.com>
   6  * Copyright (c) 2006-2007 Novell Inc.
   7  *
   8  * This file is released under the GPLv2.
   9  *
  10  *
  11  * Please see the file Documentation/kobject.txt for critical information
  12  * about using the kobject interface.
  13  */
  14
  15 #include <linux/kobject.h>
  16 #include <linux/string.h>
  17 #include <linux/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  */
  30 static 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
  47 static 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
  59 static 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
  77 static 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  */
 102 char *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 }
 117 EXPORT_SYMBOL_GPL(kobject_get_path);
 118
 119 /* add the kobject to its kset's list */
 120 static 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 */
 132 static 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
 143 static 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
 156 static 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  */
 213 int 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  */
 243 int 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 }
 254 EXPORT_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  */
 268 void 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
 291 error:
 292         printk(KERN_ERR "kobject (%p): %s\n", kobj, err_str);
 293         dump_stack();
 294 }
 295 EXPORT_SYMBOL(kobject_init);
 296
 297 static 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  */
 336 int 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 }
 358 EXPORT_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  */
 371 int 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 }
 385 EXPORT_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  */
 397 int 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
 444 out:
 445         kfree(dup_name);
 446         kfree(devpath_string);
 447         kfree(devpath);
 448         kobject_put(kobj);
 449
 450         return error;
 451 }
 452 EXPORT_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  */
 459 int 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);
 497 out:
 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  */
 509 void 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  */
 525 struct kobject *kobject_get(struct kobject *kobj)
 526 {
 527         if (kobj)
 528                 kref_get(&kobj->kref);
 529         return kobj;
 530 }
 531
 532 static 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  */
 543 static 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
 583 static 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  */
 594 void 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
 605 static void dynamic_kobj_release(struct kobject *kobj)
 606 {
 607         pr_debug("kobject: (%p): %s\n", kobj, __func__);
 608         kfree(kobj);
 609 }
 610
 611 static 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  */
 627 struct 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  */
 652 struct 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 }
 670 EXPORT_SYMBOL_GPL(kobject_create_and_add);
 671
 672 /**
 673  * kset_init - initialize a kset for use
 674  * @k: kset
 675  */
 676 void 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 */
 684 static 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
 696 static 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
 708 const 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  */
 717 int 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  */
 736 void 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  */
 752 struct 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
 770 static 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
 778 static 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  */
 798 static 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  */
 841 struct 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 }
 858 EXPORT_SYMBOL_GPL(kset_create_and_add);
 859
 860
 861 static DEFINE_SPINLOCK(kobj_ns_type_lock);
 862 static const struct kobj_ns_type_operations *kobj_ns_ops_tbl[KOBJ_NS_TYPES];
 863
 864 int 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
 886 out:
 887         spin_unlock(&kobj_ns_type_lock);
 888         return error;
 889 }
 890
 891 int 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
 903 const 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
 913 const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj)
 914 {
 915         return kobj_child_ns_ops(kobj->parent);
 916 }
 917
 918
 919 void *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
 932 const 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
 945 const 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
 958 void 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
 967 EXPORT_SYMBOL(kobject_get);
 968 EXPORT_SYMBOL(kobject_put);
 969 EXPORT_SYMBOL(kobject_del);
 970
 971 EXPORT_SYMBOL(kset_register);
 972 EXPORT_SYMBOL(kset_unregister);