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