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/module.h>
  18 #include <linux/stat.h>
  19 #include <linux/slab.h>
  20
  21 /**
  22  *      populate_dir - populate directory with attributes.
  23  *      @kobj:  object we're working on.
  24  *
  25  *      Most subsystems have a set of default attributes that
  26  *      are associated with an object that registers with them.
  27  *      This is a helper called during object registration that
  28  *      loops through the default attributes of the subsystem
  29  *      and creates attributes files for them in sysfs.
  30  *
  31  */
  32
  33 static int populate_dir(struct kobject * kobj)
  34 {
  35         struct kobj_type * t = get_ktype(kobj);
  36         struct attribute * attr;
  37         int error = 0;
  38         int i;
  39
  40         if (t && t->default_attrs) {
  41                 for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) {
  42                         if ((error = sysfs_create_file(kobj,attr)))
  43                                 break;
  44                 }
  45         }
  46         return error;
  47 }
  48
  49 static int create_dir(struct kobject * kobj)
  50 {
  51         int error = 0;
  52         if (kobject_name(kobj)) {
  53                 error = sysfs_create_dir(kobj);
  54                 if (!error) {
  55                         if ((error = populate_dir(kobj)))
  56                                 sysfs_remove_dir(kobj);
  57                 }
  58         }
  59         return error;
  60 }
  61
  62 static inline struct kobject * to_kobj(struct list_head * entry)
  63 {
  64         return container_of(entry,struct kobject,entry);
  65 }
  66
  67 static int get_kobj_path_length(struct kobject *kobj)
  68 {
  69         int length = 1;
  70         struct kobject * parent = kobj;
  71
  72         /* walk up the ancestors until we hit the one pointing to the
  73          * root.
  74          * Add 1 to strlen for leading '/' of each level.
  75          */
  76         do {
  77                 if (kobject_name(parent) == NULL)
  78                         return 0;
  79                 length += strlen(kobject_name(parent)) + 1;
  80                 parent = parent->parent;
  81         } while (parent);
  82         return length;
  83 }
  84
  85 static void fill_kobj_path(struct kobject *kobj, char *path, int length)
  86 {
  87         struct kobject * parent;
  88
  89         --length;
  90         for (parent = kobj; parent; parent = parent->parent) {
  91                 int cur = strlen(kobject_name(parent));
  92                 /* back up enough to print this name with '/' */
  93                 length -= cur;
  94                 strncpy (path + length, kobject_name(parent), cur);
  95                 *(path + --length) = '/';
  96         }
  97
  98         pr_debug("kobject: '%s' (%p): %s: path = '%s'\n", kobject_name(kobj),
  99                  kobj, __FUNCTION__,path);
 100 }
 101
 102 /**
 103  * kobject_get_path - generate and return the path associated with a given kobj and kset pair.
 104  *
 105  * @kobj:       kobject in question, with which to build the path
 106  * @gfp_mask:   the allocation type used to allocate the path
 107  *
 108  * The result must be freed by the caller with kfree().
 109  */
 110 char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask)
 111 {
 112         char *path;
 113         int len;
 114
 115         len = get_kobj_path_length(kobj);
 116         if (len == 0)
 117                 return NULL;
 118         path = kzalloc(len, gfp_mask);
 119         if (!path)
 120                 return NULL;
 121         fill_kobj_path(kobj, path, len);
 122
 123         return path;
 124 }
 125 EXPORT_SYMBOL_GPL(kobject_get_path);
 126
 127 /**
 128  *      kobject_init - initialize object.
 129  *      @kobj:  object in question.
 130  */
 131 void kobject_init(struct kobject * kobj)
 132 {
 133         if (!kobj)
 134                 return;
 135         kref_init(&kobj->kref);
 136         INIT_LIST_HEAD(&kobj->entry);
 137 }
 138
 139
 140 /**
 141  *      unlink - remove kobject from kset list.
 142  *      @kobj:  kobject.
 143  *
 144  *      Remove the kobject from the kset list and decrement
 145  *      its parent's refcount.
 146  *      This is separated out, so we can use it in both
 147  *      kobject_del() and kobject_add() on error.
 148  */
 149
 150 static void unlink(struct kobject * kobj)
 151 {
 152         if (kobj->kset) {
 153                 spin_lock(&kobj->kset->list_lock);
 154                 list_del_init(&kobj->entry);
 155                 spin_unlock(&kobj->kset->list_lock);
 156         }
 157         kobject_put(kobj);
 158 }
 159
 160 /**
 161  *      kobject_add - add an object to the hierarchy.
 162  *      @kobj:  object.
 163  */
 164
 165 int kobject_add(struct kobject * kobj)
 166 {
 167         int error = 0;
 168         struct kobject * parent;
 169
 170         if (!(kobj = kobject_get(kobj)))
 171                 return -ENOENT;
 172         if (!kobj->k_name)
 173                 kobject_set_name(kobj, "NO_NAME");
 174         if (!*kobj->k_name) {
 175                 pr_debug("kobject (%p) attempted to be registered with no "
 176                          "name!\n", kobj);
 177                 WARN_ON(1);
 178                 kobject_put(kobj);
 179                 return -EINVAL;
 180         }
 181         parent = kobject_get(kobj->parent);
 182
 183         pr_debug("kobject: '%s' (%p): %s: parent: '%s', set: '%s'\n",
 184                  kobject_name(kobj), kobj, __FUNCTION__,
 185                  parent ? kobject_name(parent) : "<NULL>",
 186                  kobj->kset ? kobject_name(&kobj->kset->kobj) : "<NULL>" );
 187
 188         if (kobj->kset) {
 189                 kobj->kset = kset_get(kobj->kset);
 190
 191                 if (!parent) {
 192                         parent = kobject_get(&kobj->kset->kobj);
 193                         /*
 194                          * If the kset is our parent, get a second
 195                          * reference, we drop both the kset and the
 196                          * parent ref on cleanup
 197                          */
 198                         kobject_get(parent);
 199                 }
 200
 201                 spin_lock(&kobj->kset->list_lock);
 202                 list_add_tail(&kobj->entry, &kobj->kset->list);
 203                 spin_unlock(&kobj->kset->list_lock);
 204                 kobj->parent = parent;
 205         }
 206
 207         error = create_dir(kobj);
 208         if (error) {
 209                 /* unlink does the kobject_put() for us */
 210                 unlink(kobj);
 211                 kobject_put(parent);
 212
 213                 /* be noisy on error issues */
 214                 if (error == -EEXIST)
 215                         printk(KERN_ERR "kobject_add failed for %s with "
 216                                "-EEXIST, don't try to register things with "
 217                                "the same name in the same directory.\n",
 218                                kobject_name(kobj));
 219                 else
 220                         printk(KERN_ERR "kobject_add failed for %s (%d)\n",
 221                                kobject_name(kobj), error);
 222                 dump_stack();
 223         }
 224
 225         return error;
 226 }
 227
 228 /**
 229  *      kobject_register - initialize and add an object.
 230  *      @kobj:  object in question.
 231  */
 232
 233 int kobject_register(struct kobject * kobj)
 234 {
 235         int error = -EINVAL;
 236         if (kobj) {
 237                 kobject_init(kobj);
 238                 error = kobject_add(kobj);
 239                 if (!error)
 240                         kobject_uevent(kobj, KOBJ_ADD);
 241         }
 242         return error;
 243 }
 244
 245 /**
 246  * kobject_set_name_vargs - Set the name of an kobject
 247  * @kobj: struct kobject to set the name of
 248  * @fmt: format string used to build the name
 249  * @vargs: vargs to format the string.
 250  */
 251 static int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
 252                                   va_list vargs)
 253 {
 254         va_list aq;
 255         char *name;
 256
 257         va_copy(aq, vargs);
 258         name = kvasprintf(GFP_KERNEL, fmt, vargs);
 259         va_end(aq);
 260
 261         if (!name)
 262                 return -ENOMEM;
 263
 264         /* Free the old name, if necessary. */
 265         kfree(kobj->k_name);
 266
 267         /* Now, set the new name */
 268         kobj->k_name = name;
 269
 270         return 0;
 271 }
 272
 273 /**
 274  * kobject_set_name - Set the name of a kobject
 275  * @kobj: struct kobject to set the name of
 276  * @fmt: format string used to build the name
 277  *
 278  * This sets the name of the kobject.  If you have already added the
 279  * kobject to the system, you must call kobject_rename() in order to
 280  * change the name of the kobject.
 281  */
 282 int kobject_set_name(struct kobject *kobj, const char *fmt, ...)
 283 {
 284         va_list args;
 285         int retval;
 286
 287         va_start(args, fmt);
 288         retval = kobject_set_name_vargs(kobj, fmt, args);
 289         va_end(args);
 290
 291         return retval;
 292 }
 293 EXPORT_SYMBOL(kobject_set_name);
 294
 295 /**
 296  * kobject_init_ng - initialize a kobject structure
 297  * @kobj: pointer to the kobject to initialize
 298  * @ktype: pointer to the ktype for this kobject.
 299  *
 300  * This function will properly initialize a kobject such that it can then
 301  * be passed to the kobject_add() call.
 302  *
 303  * After this function is called, the kobject MUST be cleaned up by a call
 304  * to kobject_put(), not by a call to kfree directly to ensure that all of
 305  * the memory is cleaned up properly.
 306  */
 307 void kobject_init_ng(struct kobject *kobj, struct kobj_type *ktype)
 308 {
 309         char *err_str;
 310
 311         if (!kobj) {
 312                 err_str = "invalid kobject pointer!";
 313                 goto error;
 314         }
 315         if (!ktype) {
 316                 err_str = "must have a ktype to be initialized properly!\n";
 317                 goto error;
 318         }
 319         if (atomic_read(&kobj->kref.refcount)) {
 320                 /* do not error out as sometimes we can recover */
 321                 printk(KERN_ERR "kobject: reference count is already set, "
 322                        "something is seriously wrong.\n");
 323                 dump_stack();
 324         }
 325
 326         kref_init(&kobj->kref);
 327         INIT_LIST_HEAD(&kobj->entry);
 328         kobj->ktype = ktype;
 329         return;
 330
 331 error:
 332         printk(KERN_ERR "kobject: %s\n", err_str);
 333         dump_stack();
 334 }
 335 EXPORT_SYMBOL(kobject_init_ng);
 336
 337 static int kobject_add_varg(struct kobject *kobj, struct kobject *parent,
 338                             const char *fmt, va_list vargs)
 339 {
 340         va_list aq;
 341         int retval;
 342
 343         va_copy(aq, vargs);
 344         retval = kobject_set_name_vargs(kobj, fmt, aq);
 345         va_end(aq);
 346         if (retval) {
 347                 printk(KERN_ERR "kobject: can not set name properly!\n");
 348                 return retval;
 349         }
 350         kobj->parent = parent;
 351         return kobject_add(kobj);
 352 }
 353
 354 /**
 355  * kobject_add_ng - the main kobject add function
 356  * @kobj: the kobject to add
 357  * @parent: pointer to the parent of the kobject.
 358  * @fmt: format to name the kobject with.
 359  *
 360  * The kobject name is set and added to the kobject hierarchy in this
 361  * function.
 362  *
 363  * If @parent is set, then the parent of the @kobj will be set to it.
 364  * If @parent is NULL, then the parent of the @kobj will be set to the
 365  * kobject associted with the kset assigned to this kobject.  If no kset
 366  * is assigned to the kobject, then the kobject will be located in the
 367  * root of the sysfs tree.
 368  *
 369  * If this function returns an error, kobject_put() must be called to
 370  * properly clean up the memory associated with the object.
 371  *
 372  * If the function is successful, the only way to properly clean up the
 373  * memory is with a call to kobject_del(), in which case, a call to
 374  * kobject_put() is not necessary (kobject_del() does the final
 375  * kobject_put() to call the release function in the ktype's release
 376  * pointer.)
 377  *
 378  * Under no instance should the kobject that is passed to this function
 379  * be directly freed with a call to kfree(), that can leak memory.
 380  *
 381  * Note, no uevent will be created with this call, the caller should set
 382  * up all of the necessary sysfs files for the object and then call
 383  * kobject_uevent() with the UEVENT_ADD parameter to ensure that
 384  * userspace is properly notified of this kobject's creation.
 385  */
 386 int kobject_add_ng(struct kobject *kobj, struct kobject *parent,
 387                    const char *fmt, ...)
 388 {
 389         va_list args;
 390         int retval;
 391
 392         if (!kobj)
 393                 return -EINVAL;
 394
 395         va_start(args, fmt);
 396         retval = kobject_add_varg(kobj, parent, fmt, args);
 397         va_end(args);
 398
 399         return retval;
 400 }
 401 EXPORT_SYMBOL(kobject_add_ng);
 402
 403 /**
 404  * kobject_init_and_add - initialize a kobject structure and add it to the kobject hierarchy
 405  * @kobj: pointer to the kobject to initialize
 406  * @ktype: pointer to the ktype for this kobject.
 407  * @parent: pointer to the parent of this kobject.
 408  * @fmt: the name of the kobject.
 409  *
 410  * This function combines the call to kobject_init_ng() and
 411  * kobject_add_ng().  The same type of error handling after a call to
 412  * kobject_add_ng() and kobject lifetime rules are the same here.
 413  */
 414 int kobject_init_and_add(struct kobject *kobj, struct kobj_type *ktype,
 415                          struct kobject *parent, const char *fmt, ...)
 416 {
 417         va_list args;
 418         int retval;
 419
 420         kobject_init_ng(kobj, ktype);
 421
 422         va_start(args, fmt);
 423         retval = kobject_add_varg(kobj, parent, fmt, args);
 424         va_end(args);
 425
 426         return retval;
 427 }
 428 EXPORT_SYMBOL_GPL(kobject_init_and_add);
 429
 430 /**
 431  *      kobject_rename - change the name of an object
 432  *      @kobj:  object in question.
 433  *      @new_name: object's new name
 434  */
 435
 436 int kobject_rename(struct kobject * kobj, const char *new_name)
 437 {
 438         int error = 0;
 439         const char *devpath = NULL;
 440         char *devpath_string = NULL;
 441         char *envp[2];
 442
 443         kobj = kobject_get(kobj);
 444         if (!kobj)
 445                 return -EINVAL;
 446         if (!kobj->parent)
 447                 return -EINVAL;
 448
 449         /* see if this name is already in use */
 450         if (kobj->kset) {
 451                 struct kobject *temp_kobj;
 452                 temp_kobj = kset_find_obj(kobj->kset, new_name);
 453                 if (temp_kobj) {
 454                         printk(KERN_WARNING "kobject '%s' cannot be renamed "
 455                                "to '%s' as '%s' is already in existence.\n",
 456                                kobject_name(kobj), new_name, new_name);
 457                         kobject_put(temp_kobj);
 458                         return -EINVAL;
 459                 }
 460         }
 461
 462         devpath = kobject_get_path(kobj, GFP_KERNEL);
 463         if (!devpath) {
 464                 error = -ENOMEM;
 465                 goto out;
 466         }
 467         devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
 468         if (!devpath_string) {
 469                 error = -ENOMEM;
 470                 goto out;
 471         }
 472         sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
 473         envp[0] = devpath_string;
 474         envp[1] = NULL;
 475
 476         error = sysfs_rename_dir(kobj, new_name);
 477
 478         /* This function is mostly/only used for network interface.
 479          * Some hotplug package track interfaces by their name and
 480          * therefore want to know when the name is changed by the user. */
 481         if (!error)
 482                 kobject_uevent_env(kobj, KOBJ_MOVE, envp);
 483
 484 out:
 485         kfree(devpath_string);
 486         kfree(devpath);
 487         kobject_put(kobj);
 488
 489         return error;
 490 }
 491
 492 /**
 493  *      kobject_move - move object to another parent
 494  *      @kobj:  object in question.
 495  *      @new_parent: object's new parent (can be NULL)
 496  */
 497
 498 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
 499 {
 500         int error;
 501         struct kobject *old_parent;
 502         const char *devpath = NULL;
 503         char *devpath_string = NULL;
 504         char *envp[2];
 505
 506         kobj = kobject_get(kobj);
 507         if (!kobj)
 508                 return -EINVAL;
 509         new_parent = kobject_get(new_parent);
 510         if (!new_parent) {
 511                 if (kobj->kset)
 512                         new_parent = kobject_get(&kobj->kset->kobj);
 513         }
 514         /* old object path */
 515         devpath = kobject_get_path(kobj, GFP_KERNEL);
 516         if (!devpath) {
 517                 error = -ENOMEM;
 518                 goto out;
 519         }
 520         devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
 521         if (!devpath_string) {
 522                 error = -ENOMEM;
 523                 goto out;
 524         }
 525         sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
 526         envp[0] = devpath_string;
 527         envp[1] = NULL;
 528         error = sysfs_move_dir(kobj, new_parent);
 529         if (error)
 530                 goto out;
 531         old_parent = kobj->parent;
 532         kobj->parent = new_parent;
 533         new_parent = NULL;
 534         kobject_put(old_parent);
 535         kobject_uevent_env(kobj, KOBJ_MOVE, envp);
 536 out:
 537         kobject_put(new_parent);
 538         kobject_put(kobj);
 539         kfree(devpath_string);
 540         kfree(devpath);
 541         return error;
 542 }
 543
 544 /**
 545  *      kobject_del - unlink kobject from hierarchy.
 546  *      @kobj:  object.
 547  */
 548
 549 void kobject_del(struct kobject * kobj)
 550 {
 551         if (!kobj)
 552                 return;
 553         sysfs_remove_dir(kobj);
 554         unlink(kobj);
 555 }
 556
 557 /**
 558  *      kobject_unregister - remove object from hierarchy and decrement refcount.
 559  *      @kobj:  object going away.
 560  */
 561
 562 void kobject_unregister(struct kobject * kobj)
 563 {
 564         if (!kobj)
 565                 return;
 566         pr_debug("kobject: '%s' (%p): %s\n",
 567                  kobject_name(kobj), kobj, __FUNCTION__);
 568         kobject_uevent(kobj, KOBJ_REMOVE);
 569         kobject_del(kobj);
 570         kobject_put(kobj);
 571 }
 572
 573 /**
 574  *      kobject_get - increment refcount for object.
 575  *      @kobj:  object.
 576  */
 577
 578 struct kobject * kobject_get(struct kobject * kobj)
 579 {
 580         if (kobj)
 581                 kref_get(&kobj->kref);
 582         return kobj;
 583 }
 584
 585 /*
 586  * kobject_cleanup - free kobject resources.
 587  * @kobj: object to cleanup
 588  */
 589 static void kobject_cleanup(struct kobject *kobj)
 590 {
 591         struct kobj_type * t = get_ktype(kobj);
 592         struct kset * s = kobj->kset;
 593         struct kobject * parent = kobj->parent;
 594         const char *name = kobj->k_name;
 595
 596         pr_debug("kobject: '%s' (%p): %s\n",
 597                  kobject_name(kobj), kobj, __FUNCTION__);
 598         if (t && t->release) {
 599                 t->release(kobj);
 600                 /* If we have a release function, we can guess that this was
 601                  * not a statically allocated kobject, so we should be safe to
 602                  * free the name */
 603                 kfree(name);
 604         }
 605         if (s)
 606                 kset_put(s);
 607         kobject_put(parent);
 608 }
 609
 610 static void kobject_release(struct kref *kref)
 611 {
 612         kobject_cleanup(container_of(kref, struct kobject, kref));
 613 }
 614
 615 /**
 616  *      kobject_put - decrement refcount for object.
 617  *      @kobj:  object.
 618  *
 619  *      Decrement the refcount, and if 0, call kobject_cleanup().
 620  */
 621 void kobject_put(struct kobject * kobj)
 622 {
 623         if (kobj)
 624                 kref_put(&kobj->kref, kobject_release);
 625 }
 626
 627 static void dynamic_kobj_release(struct kobject *kobj)
 628 {
 629         pr_debug("kobject: '%s' (%p): %s\n",
 630                  kobject_name(kobj), kobj, __FUNCTION__);
 631         kfree(kobj);
 632 }
 633
 634 static struct kobj_type dynamic_kobj_ktype = {
 635         .release        = dynamic_kobj_release,
 636         .sysfs_ops      = &kobj_sysfs_ops,
 637 };
 638
 639 /**
 640  * kobject_create - create a struct kobject dynamically
 641  *
 642  * This function creates a kobject structure dynamically and sets it up
 643  * to be a "dynamic" kobject with a default release function set up.
 644  *
 645  * If the kobject was not able to be created, NULL will be returned.
 646  * The kobject structure returned from here must be cleaned up with a
 647  * call to kobject_put() and not kfree(), as kobject_init_ng() has
 648  * already been called on this structure.
 649  */
 650 struct kobject *kobject_create(void)
 651 {
 652         struct kobject *kobj;
 653
 654         kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
 655         if (!kobj)
 656                 return NULL;
 657
 658         kobject_init_ng(kobj, &dynamic_kobj_ktype);
 659         return kobj;
 660 }
 661
 662 /**
 663  * kobject_create_and_add - create a struct kobject dynamically and register it with sysfs
 664  *
 665  * @name: the name for the kset
 666  * @parent: the parent kobject of this kobject, if any.
 667  *
 668  * This function creates a kset structure dynamically and registers it
 669  * with sysfs.  When you are finished with this structure, call
 670  * kobject_unregister() and the structure will be dynamically freed when
 671  * it is no longer being used.
 672  *
 673  * If the kobject was not able to be created, NULL will be returned.
 674  */
 675 struct kobject *kobject_create_and_add(const char *name, struct kobject *parent)
 676 {
 677         struct kobject *kobj;
 678         int retval;
 679
 680         kobj = kobject_create();
 681         if (!kobj)
 682                 return NULL;
 683
 684         retval = kobject_add_ng(kobj, parent, "%s", name);
 685         if (retval) {
 686                 printk(KERN_WARNING "%s: kobject_add error: %d\n",
 687                        __FUNCTION__, retval);
 688                 kobject_put(kobj);
 689                 kobj = NULL;
 690         }
 691         return kobj;
 692 }
 693 EXPORT_SYMBOL_GPL(kobject_create_and_add);
 694
 695 /**
 696  *      kset_init - initialize a kset for use
 697  *      @k:     kset
 698  */
 699
 700 void kset_init(struct kset * k)
 701 {
 702         kobject_init(&k->kobj);
 703         INIT_LIST_HEAD(&k->list);
 704         spin_lock_init(&k->list_lock);
 705 }
 706
 707 /* default kobject attribute operations */
 708 static ssize_t kobj_attr_show(struct kobject *kobj, struct attribute *attr,
 709                               char *buf)
 710 {
 711         struct kobj_attribute *kattr;
 712         ssize_t ret = -EIO;
 713
 714         kattr = container_of(attr, struct kobj_attribute, attr);
 715         if (kattr->show)
 716                 ret = kattr->show(kobj, kattr, buf);
 717         return ret;
 718 }
 719
 720 static ssize_t kobj_attr_store(struct kobject *kobj, struct attribute *attr,
 721                                const char *buf, size_t count)
 722 {
 723         struct kobj_attribute *kattr;
 724         ssize_t ret = -EIO;
 725
 726         kattr = container_of(attr, struct kobj_attribute, attr);
 727         if (kattr->store)
 728                 ret = kattr->store(kobj, kattr, buf, count);
 729         return ret;
 730 }
 731
 732 struct sysfs_ops kobj_sysfs_ops = {
 733         .show   = kobj_attr_show,
 734         .store  = kobj_attr_store,
 735 };
 736
 737 /**
 738  *      kset_add - add a kset object to the hierarchy.
 739  *      @k:     kset.
 740  */
 741
 742 int kset_add(struct kset * k)
 743 {
 744         return kobject_add(&k->kobj);
 745 }
 746
 747
 748 /**
 749  *      kset_register - initialize and add a kset.
 750  *      @k:     kset.
 751  */
 752
 753 int kset_register(struct kset * k)
 754 {
 755         int err;
 756
 757         if (!k)
 758                 return -EINVAL;
 759
 760         kset_init(k);
 761         err = kset_add(k);
 762         if (err)
 763                 return err;
 764         kobject_uevent(&k->kobj, KOBJ_ADD);
 765         return 0;
 766 }
 767
 768
 769 /**
 770  *      kset_unregister - remove a kset.
 771  *      @k:     kset.
 772  */
 773
 774 void kset_unregister(struct kset * k)
 775 {
 776         if (!k)
 777                 return;
 778         kobject_unregister(&k->kobj);
 779 }
 780
 781
 782 /**
 783  *      kset_find_obj - search for object in kset.
 784  *      @kset:  kset we're looking in.
 785  *      @name:  object's name.
 786  *
 787  *      Lock kset via @kset->subsys, and iterate over @kset->list,
 788  *      looking for a matching kobject. If matching object is found
 789  *      take a reference and return the object.
 790  */
 791
 792 struct kobject * kset_find_obj(struct kset * kset, const char * name)
 793 {
 794         struct list_head * entry;
 795         struct kobject * ret = NULL;
 796
 797         spin_lock(&kset->list_lock);
 798         list_for_each(entry,&kset->list) {
 799                 struct kobject * k = to_kobj(entry);
 800                 if (kobject_name(k) && !strcmp(kobject_name(k),name)) {
 801                         ret = kobject_get(k);
 802                         break;
 803                 }
 804         }
 805         spin_unlock(&kset->list_lock);
 806         return ret;
 807 }
 808
 809 static void kset_release(struct kobject *kobj)
 810 {
 811         struct kset *kset = container_of(kobj, struct kset, kobj);
 812         pr_debug("kobject: '%s' (%p): %s\n",
 813                  kobject_name(kobj), kobj, __FUNCTION__);
 814         kfree(kset);
 815 }
 816
 817 static struct kobj_type kset_ktype = {
 818         .sysfs_ops      = &kobj_sysfs_ops,
 819         .release = kset_release,
 820 };
 821
 822 /**
 823  * kset_create - create a struct kset dynamically
 824  *
 825  * @name: the name for the kset
 826  * @uevent_ops: a struct kset_uevent_ops for the kset
 827  * @parent_kobj: the parent kobject of this kset, if any.
 828  *
 829  * This function creates a kset structure dynamically.  This structure can
 830  * then be registered with the system and show up in sysfs with a call to
 831  * kset_register().  When you are finished with this structure, if
 832  * kset_register() has been called, call kset_unregister() and the
 833  * structure will be dynamically freed when it is no longer being used.
 834  *
 835  * If the kset was not able to be created, NULL will be returned.
 836  */
 837 static struct kset *kset_create(const char *name,
 838                                 struct kset_uevent_ops *uevent_ops,
 839                                 struct kobject *parent_kobj)
 840 {
 841         struct kset *kset;
 842
 843         kset = kzalloc(sizeof(*kset), GFP_KERNEL);
 844         if (!kset)
 845                 return NULL;
 846         kobject_set_name(&kset->kobj, name);
 847         kset->uevent_ops = uevent_ops;
 848         kset->kobj.parent = parent_kobj;
 849
 850         /*
 851          * The kobject of this kset will have a type of kset_ktype and belong to
 852          * no kset itself.  That way we can properly free it when it is
 853          * finished being used.
 854          */
 855         kset->kobj.ktype = &kset_ktype;
 856         kset->kobj.kset = NULL;
 857
 858         return kset;
 859 }
 860
 861 /**
 862  * kset_create_and_add - create a struct kset dynamically and add it to sysfs
 863  *
 864  * @name: the name for the kset
 865  * @uevent_ops: a struct kset_uevent_ops for the kset
 866  * @parent_kobj: the parent kobject of this kset, if any.
 867  *
 868  * This function creates a kset structure dynamically and registers it
 869  * with sysfs.  When you are finished with this structure, call
 870  * kset_unregister() and the structure will be dynamically freed when it
 871  * is no longer being used.
 872  *
 873  * If the kset was not able to be created, NULL will be returned.
 874  */
 875 struct kset *kset_create_and_add(const char *name,
 876                                  struct kset_uevent_ops *uevent_ops,
 877                                  struct kobject *parent_kobj)
 878 {
 879         struct kset *kset;
 880         int error;
 881
 882         kset = kset_create(name, uevent_ops, parent_kobj);
 883         if (!kset)
 884                 return NULL;
 885         error = kset_register(kset);
 886         if (error) {
 887                 kfree(kset);
 888                 return NULL;
 889         }
 890         return kset;
 891 }
 892 EXPORT_SYMBOL_GPL(kset_create_and_add);
 893
 894 EXPORT_SYMBOL(kobject_init);
 895 EXPORT_SYMBOL(kobject_register);
 896 EXPORT_SYMBOL(kobject_unregister);
 897 EXPORT_SYMBOL(kobject_get);
 898 EXPORT_SYMBOL(kobject_put);
 899 EXPORT_SYMBOL(kobject_add);
 900 EXPORT_SYMBOL(kobject_del);
 901
 902 EXPORT_SYMBOL(kset_register);
 903 EXPORT_SYMBOL(kset_unregister);