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