drivers/acpi/acpica/utdelete.c

   1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
   2 /*******************************************************************************
   3  *
   4  * Module Name: utdelete - object deletion and reference count utilities
   5  *
   6  ******************************************************************************/
   7
   8 #include <acpi/acpi.h>
   9 #include "accommon.h"
  10 #include "acinterp.h"
  11 #include "acnamesp.h"
  12 #include "acevents.h"
  13
  14 #define _COMPONENT          ACPI_UTILITIES
  15 ACPI_MODULE_NAME("utdelete")
  16
  17 /* Local prototypes */
  18 static void acpi_ut_delete_internal_obj(union acpi_operand_object *object);
  19
  20 static void
  21 acpi_ut_update_ref_count(union acpi_operand_object *object, u32 action);
  22
  23 /*******************************************************************************
  24  *
  25  * FUNCTION:    acpi_ut_delete_internal_obj
  26  *
  27  * PARAMETERS:  object         - Object to be deleted
  28  *
  29  * RETURN:      None
  30  *
  31  * DESCRIPTION: Low level object deletion, after reference counts have been
  32  *              updated (All reference counts, including sub-objects!)
  33  *
  34  ******************************************************************************/
  35
  36 static void acpi_ut_delete_internal_obj(union acpi_operand_object *object)
  37 {
  38         void *obj_pointer = NULL;
  39         union acpi_operand_object *handler_desc;
  40         union acpi_operand_object *second_desc;
  41         union acpi_operand_object *next_desc;
  42         union acpi_operand_object *start_desc;
  43         union acpi_operand_object **last_obj_ptr;
  44
  45         ACPI_FUNCTION_TRACE_PTR(ut_delete_internal_obj, object);
  46
  47         if (!object) {
  48                 return_VOID;
  49         }
  50
  51         /*
  52          * Must delete or free any pointers within the object that are not
  53          * actual ACPI objects (for example, a raw buffer pointer).
  54          */
  55         switch (object->common.type) {
  56         case ACPI_TYPE_STRING:
  57
  58                 ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
  59                                   "**** String %p, ptr %p\n", object,
  60                                   object->string.pointer));
  61
  62                 /* Free the actual string buffer */
  63
  64                 if (!(object->common.flags & AOPOBJ_STATIC_POINTER)) {
  65
  66                         /* But only if it is NOT a pointer into an ACPI table */
  67
  68                         obj_pointer = object->string.pointer;
  69                 }
  70                 break;
  71
  72         case ACPI_TYPE_BUFFER:
  73
  74                 ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
  75                                   "**** Buffer %p, ptr %p\n", object,
  76                                   object->buffer.pointer));
  77
  78                 /* Free the actual buffer */
  79
  80                 if (!(object->common.flags & AOPOBJ_STATIC_POINTER)) {
  81
  82                         /* But only if it is NOT a pointer into an ACPI table */
  83
  84                         obj_pointer = object->buffer.pointer;
  85                 }
  86                 break;
  87
  88         case ACPI_TYPE_PACKAGE:
  89
  90                 ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
  91                                   " **** Package of count %X\n",
  92                                   object->package.count));
  93
  94                 /*
  95                  * Elements of the package are not handled here, they are deleted
  96                  * separately
  97                  */
  98
  99                 /* Free the (variable length) element pointer array */
 100
 101                 obj_pointer = object->package.elements;
 102                 break;
 103
 104                 /*
 105                  * These objects have a possible list of notify handlers.
 106                  * Device object also may have a GPE block.
 107                  */
 108         case ACPI_TYPE_DEVICE:
 109
 110                 if (object->device.gpe_block) {
 111                         (void)acpi_ev_delete_gpe_block(object->device.
 112                                                        gpe_block);
 113                 }
 114
 115                 /*lint -fallthrough */
 116
 117         case ACPI_TYPE_PROCESSOR:
 118         case ACPI_TYPE_THERMAL:
 119
 120                 /* Walk the address handler list for this object */
 121
 122                 handler_desc = object->common_notify.handler;
 123                 while (handler_desc) {
 124                         next_desc = handler_desc->address_space.next;
 125                         acpi_ut_remove_reference(handler_desc);
 126                         handler_desc = next_desc;
 127                 }
 128                 break;
 129
 130         case ACPI_TYPE_MUTEX:
 131
 132                 ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
 133                                   "***** Mutex %p, OS Mutex %p\n",
 134                                   object, object->mutex.os_mutex));
 135
 136                 if (object == acpi_gbl_global_lock_mutex) {
 137
 138                         /* Global Lock has extra semaphore */
 139
 140                         (void)
 141                             acpi_os_delete_semaphore
 142                             (acpi_gbl_global_lock_semaphore);
 143                         acpi_gbl_global_lock_semaphore = NULL;
 144
 145                         acpi_os_delete_mutex(object->mutex.os_mutex);
 146                         acpi_gbl_global_lock_mutex = NULL;
 147                 } else {
 148                         acpi_ex_unlink_mutex(object);
 149                         acpi_os_delete_mutex(object->mutex.os_mutex);
 150                 }
 151                 break;
 152
 153         case ACPI_TYPE_EVENT:
 154
 155                 ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
 156                                   "***** Event %p, OS Semaphore %p\n",
 157                                   object, object->event.os_semaphore));
 158
 159                 (void)acpi_os_delete_semaphore(object->event.os_semaphore);
 160                 object->event.os_semaphore = NULL;
 161                 break;
 162
 163         case ACPI_TYPE_METHOD:
 164
 165                 ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
 166                                   "***** Method %p\n", object));
 167
 168                 /* Delete the method mutex if it exists */
 169
 170                 if (object->method.mutex) {
 171                         acpi_os_delete_mutex(object->method.mutex->mutex.
 172                                              os_mutex);
 173                         acpi_ut_delete_object_desc(object->method.mutex);
 174                         object->method.mutex = NULL;
 175                 }
 176
 177                 if (object->method.node) {
 178                         object->method.node = NULL;
 179                 }
 180                 break;
 181
 182         case ACPI_TYPE_REGION:
 183
 184                 ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
 185                                   "***** Region %p\n", object));
 186
 187                 /*
 188                  * Update address_range list. However, only permanent regions
 189                  * are installed in this list. (Not created within a method)
 190                  */
 191                 if (!(object->region.node->flags & ANOBJ_TEMPORARY)) {
 192                         acpi_ut_remove_address_range(object->region.space_id,
 193                                                      object->region.node);
 194                 }
 195
 196                 second_desc = acpi_ns_get_secondary_object(object);
 197                 if (second_desc) {
 198                         /*
 199                          * Free the region_context if and only if the handler is one of the
 200                          * default handlers -- and therefore, we created the context object
 201                          * locally, it was not created by an external caller.
 202                          */
 203                         handler_desc = object->region.handler;
 204                         if (handler_desc) {
 205                                 next_desc =
 206                                     handler_desc->address_space.region_list;
 207                                 start_desc = next_desc;
 208                                 last_obj_ptr =
 209                                     &handler_desc->address_space.region_list;
 210
 211                                 /* Remove the region object from the handler list */
 212
 213                                 while (next_desc) {
 214                                         if (next_desc == object) {
 215                                                 *last_obj_ptr =
 216                                                     next_desc->region.next;
 217                                                 break;
 218                                         }
 219
 220                                         /* Walk the linked list of handlers */
 221
 222                                         last_obj_ptr = &next_desc->region.next;
 223                                         next_desc = next_desc->region.next;
 224
 225                                         /* Prevent infinite loop if list is corrupted */
 226
 227                                         if (next_desc == start_desc) {
 228                                                 ACPI_ERROR((AE_INFO,
 229                                                             "Circular region list in address handler object %p",
 230                                                             handler_desc));
 231                                                 return_VOID;
 232                                         }
 233                                 }
 234
 235                                 if (handler_desc->address_space.handler_flags &
 236                                     ACPI_ADDR_HANDLER_DEFAULT_INSTALLED) {
 237
 238                                         /* Deactivate region and free region context */
 239
 240                                         if (handler_desc->address_space.setup) {
 241                                                 (void)handler_desc->
 242                                                     address_space.setup(object,
 243                                                                         ACPI_REGION_DEACTIVATE,
 244                                                                         handler_desc->
 245                                                                         address_space.
 246                                                                         context,
 247                                                                         &second_desc->
 248                                                                         extra.
 249                                                                         region_context);
 250                                         }
 251                                 }
 252
 253                                 acpi_ut_remove_reference(handler_desc);
 254                         }
 255
 256                         /* Now we can free the Extra object */
 257
 258                         acpi_ut_delete_object_desc(second_desc);
 259                 }
 260                 break;
 261
 262         case ACPI_TYPE_BUFFER_FIELD:
 263
 264                 ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
 265                                   "***** Buffer Field %p\n", object));
 266
 267                 second_desc = acpi_ns_get_secondary_object(object);
 268                 if (second_desc) {
 269                         acpi_ut_delete_object_desc(second_desc);
 270                 }
 271                 break;
 272
 273         case ACPI_TYPE_LOCAL_BANK_FIELD:
 274
 275                 ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
 276                                   "***** Bank Field %p\n", object));
 277
 278                 second_desc = acpi_ns_get_secondary_object(object);
 279                 if (second_desc) {
 280                         acpi_ut_delete_object_desc(second_desc);
 281                 }
 282                 break;
 283
 284         default:
 285
 286                 break;
 287         }
 288
 289         /* Free any allocated memory (pointer within the object) found above */
 290
 291         if (obj_pointer) {
 292                 ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
 293                                   "Deleting Object Subptr %p\n", obj_pointer));
 294                 ACPI_FREE(obj_pointer);
 295         }
 296
 297         /* Now the object can be safely deleted */
 298
 299         ACPI_DEBUG_PRINT_RAW((ACPI_DB_ALLOCATIONS,
 300                               "%s: Deleting Object %p [%s]\n",
 301                               ACPI_GET_FUNCTION_NAME, object,
 302                               acpi_ut_get_object_type_name(object)));
 303
 304         acpi_ut_delete_object_desc(object);
 305         return_VOID;
 306 }
 307
 308 /*******************************************************************************
 309  *
 310  * FUNCTION:    acpi_ut_delete_internal_object_list
 311  *
 312  * PARAMETERS:  obj_list        - Pointer to the list to be deleted
 313  *
 314  * RETURN:      None
 315  *
 316  * DESCRIPTION: This function deletes an internal object list, including both
 317  *              simple objects and package objects
 318  *
 319  ******************************************************************************/
 320
 321 void acpi_ut_delete_internal_object_list(union acpi_operand_object **obj_list)
 322 {
 323         union acpi_operand_object **internal_obj;
 324
 325         ACPI_FUNCTION_ENTRY();
 326
 327         /* Walk the null-terminated internal list */
 328
 329         for (internal_obj = obj_list; *internal_obj; internal_obj++) {
 330                 acpi_ut_remove_reference(*internal_obj);
 331         }
 332
 333         /* Free the combined parameter pointer list and object array */
 334
 335         ACPI_FREE(obj_list);
 336         return;
 337 }
 338
 339 /*******************************************************************************
 340  *
 341  * FUNCTION:    acpi_ut_update_ref_count
 342  *
 343  * PARAMETERS:  object          - Object whose ref count is to be updated
 344  *              action          - What to do (REF_INCREMENT or REF_DECREMENT)
 345  *
 346  * RETURN:      None. Sets new reference count within the object
 347  *
 348  * DESCRIPTION: Modify the reference count for an internal acpi object
 349  *
 350  ******************************************************************************/
 351
 352 static void
 353 acpi_ut_update_ref_count(union acpi_operand_object *object, u32 action)
 354 {
 355         u16 original_count;
 356         u16 new_count = 0;
 357         acpi_cpu_flags lock_flags;
 358         char *message;
 359
 360         ACPI_FUNCTION_NAME(ut_update_ref_count);
 361
 362         if (!object) {
 363                 return;
 364         }
 365
 366         /*
 367          * Always get the reference count lock. Note: Interpreter and/or
 368          * Namespace is not always locked when this function is called.
 369          */
 370         lock_flags = acpi_os_acquire_lock(acpi_gbl_reference_count_lock);
 371         original_count = object->common.reference_count;
 372
 373         /* Perform the reference count action (increment, decrement) */
 374
 375         switch (action) {
 376         case REF_INCREMENT:
 377
 378                 new_count = original_count + 1;
 379                 object->common.reference_count = new_count;
 380                 acpi_os_release_lock(acpi_gbl_reference_count_lock, lock_flags);
 381
 382                 /* The current reference count should never be zero here */
 383
 384                 if (!original_count) {
 385                         ACPI_WARNING((AE_INFO,
 386                                       "Obj %p, Reference Count was zero before increment\n",
 387                                       object));
 388                 }
 389
 390                 ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
 391                                   "Obj %p Type %.2X [%s] Refs %.2X [Incremented]\n",
 392                                   object, object->common.type,
 393                                   acpi_ut_get_object_type_name(object),
 394                                   new_count));
 395                 message = "Incremement";
 396                 break;
 397
 398         case REF_DECREMENT:
 399
 400                 /* The current reference count must be non-zero */
 401
 402                 if (original_count) {
 403                         new_count = original_count - 1;
 404                         object->common.reference_count = new_count;
 405                 }
 406
 407                 acpi_os_release_lock(acpi_gbl_reference_count_lock, lock_flags);
 408
 409                 if (!original_count) {
 410                         ACPI_WARNING((AE_INFO,
 411                                       "Obj %p, Reference Count is already zero, cannot decrement\n",
 412                                       object));
 413                         return;
 414                 }
 415
 416                 ACPI_DEBUG_PRINT_RAW((ACPI_DB_ALLOCATIONS,
 417                                       "%s: Obj %p Type %.2X Refs %.2X [Decremented]\n",
 418                                       ACPI_GET_FUNCTION_NAME, object,
 419                                       object->common.type, new_count));
 420
 421                 /* Actually delete the object on a reference count of zero */
 422
 423                 if (new_count == 0) {
 424                         acpi_ut_delete_internal_obj(object);
 425                 }
 426                 message = "Decrement";
 427                 break;
 428
 429         default:
 430
 431                 acpi_os_release_lock(acpi_gbl_reference_count_lock, lock_flags);
 432                 ACPI_ERROR((AE_INFO, "Unknown Reference Count action (0x%X)",
 433                             action));
 434                 return;
 435         }
 436
 437         /*
 438          * Sanity check the reference count, for debug purposes only.
 439          * (A deleted object will have a huge reference count)
 440          */
 441         if (new_count > ACPI_MAX_REFERENCE_COUNT) {
 442                 ACPI_WARNING((AE_INFO,
 443                               "Large Reference Count (0x%X) in object %p, Type=0x%.2X Operation=%s",
 444                               new_count, object, object->common.type, message));
 445         }
 446 }
 447
 448 /*******************************************************************************
 449  *
 450  * FUNCTION:    acpi_ut_update_object_reference
 451  *
 452  * PARAMETERS:  object              - Increment ref count for this object
 453  *                                    and all sub-objects
 454  *              action              - Either REF_INCREMENT or REF_DECREMENT
 455  *
 456  * RETURN:      Status
 457  *
 458  * DESCRIPTION: Increment the object reference count
 459  *
 460  * Object references are incremented when:
 461  * 1) An object is attached to a Node (namespace object)
 462  * 2) An object is copied (all subobjects must be incremented)
 463  *
 464  * Object references are decremented when:
 465  * 1) An object is detached from an Node
 466  *
 467  ******************************************************************************/
 468
 469 acpi_status
 470 acpi_ut_update_object_reference(union acpi_operand_object *object, u16 action)
 471 {
 472         acpi_status status = AE_OK;
 473         union acpi_generic_state *state_list = NULL;
 474         union acpi_operand_object *next_object = NULL;
 475         union acpi_operand_object *prev_object;
 476         union acpi_generic_state *state;
 477         u32 i;
 478
 479         ACPI_FUNCTION_NAME(ut_update_object_reference);
 480
 481         while (object) {
 482
 483                 /* Make sure that this isn't a namespace handle */
 484
 485                 if (ACPI_GET_DESCRIPTOR_TYPE(object) == ACPI_DESC_TYPE_NAMED) {
 486                         ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
 487                                           "Object %p is NS handle\n", object));
 488                         return (AE_OK);
 489                 }
 490
 491                 /*
 492                  * All sub-objects must have their reference count incremented
 493                  * also. Different object types have different subobjects.
 494                  */
 495                 switch (object->common.type) {
 496                 case ACPI_TYPE_DEVICE:
 497                 case ACPI_TYPE_PROCESSOR:
 498                 case ACPI_TYPE_POWER:
 499                 case ACPI_TYPE_THERMAL:
 500                         /*
 501                          * Update the notify objects for these types (if present)
 502                          * Two lists, system and device notify handlers.
 503                          */
 504                         for (i = 0; i < ACPI_NUM_NOTIFY_TYPES; i++) {
 505                                 prev_object =
 506                                     object->common_notify.notify_list[i];
 507                                 while (prev_object) {
 508                                         next_object =
 509                                             prev_object->notify.next[i];
 510                                         acpi_ut_update_ref_count(prev_object,
 511                                                                  action);
 512                                         prev_object = next_object;
 513                                 }
 514                         }
 515                         break;
 516
 517                 case ACPI_TYPE_PACKAGE:
 518                         /*
 519                          * We must update all the sub-objects of the package,
 520                          * each of whom may have their own sub-objects.
 521                          */
 522                         for (i = 0; i < object->package.count; i++) {
 523                                 /*
 524                                  * Null package elements are legal and can be simply
 525                                  * ignored.
 526                                  */
 527                                 next_object = object->package.elements[i];
 528                                 if (!next_object) {
 529                                         continue;
 530                                 }
 531
 532                                 switch (next_object->common.type) {
 533                                 case ACPI_TYPE_INTEGER:
 534                                 case ACPI_TYPE_STRING:
 535                                 case ACPI_TYPE_BUFFER:
 536                                         /*
 537                                          * For these very simple sub-objects, we can just
 538                                          * update the reference count here and continue.
 539                                          * Greatly increases performance of this operation.
 540                                          */
 541                                         acpi_ut_update_ref_count(next_object,
 542                                                                  action);
 543                                         break;
 544
 545                                 default:
 546                                         /*
 547                                          * For complex sub-objects, push them onto the stack
 548                                          * for later processing (this eliminates recursion.)
 549                                          */
 550                                         status =
 551                                             acpi_ut_create_update_state_and_push
 552                                             (next_object, action, &state_list);
 553                                         if (ACPI_FAILURE(status)) {
 554                                                 goto error_exit;
 555                                         }
 556                                         break;
 557                                 }
 558                         }
 559                         next_object = NULL;
 560                         break;
 561
 562                 case ACPI_TYPE_BUFFER_FIELD:
 563
 564                         next_object = object->buffer_field.buffer_obj;
 565                         break;
 566
 567                 case ACPI_TYPE_LOCAL_BANK_FIELD:
 568
 569                         next_object = object->bank_field.bank_obj;
 570                         status =
 571                             acpi_ut_create_update_state_and_push(object->
 572                                                                  bank_field.
 573                                                                  region_obj,
 574                                                                  action,
 575                                                                  &state_list);
 576                         if (ACPI_FAILURE(status)) {
 577                                 goto error_exit;
 578                         }
 579                         break;
 580
 581                 case ACPI_TYPE_LOCAL_INDEX_FIELD:
 582
 583                         next_object = object->index_field.index_obj;
 584                         status =
 585                             acpi_ut_create_update_state_and_push(object->
 586                                                                  index_field.
 587                                                                  data_obj,
 588                                                                  action,
 589                                                                  &state_list);
 590                         if (ACPI_FAILURE(status)) {
 591                                 goto error_exit;
 592                         }
 593                         break;
 594
 595                 case ACPI_TYPE_LOCAL_REFERENCE:
 596                         /*
 597                          * The target of an Index (a package, string, or buffer) or a named
 598                          * reference must track changes to the ref count of the index or
 599                          * target object.
 600                          */
 601                         if ((object->reference.class == ACPI_REFCLASS_INDEX) ||
 602                             (object->reference.class == ACPI_REFCLASS_NAME)) {
 603                                 next_object = object->reference.object;
 604                         }
 605                         break;
 606
 607                 case ACPI_TYPE_LOCAL_REGION_FIELD:
 608                 case ACPI_TYPE_REGION:
 609                 default:
 610
 611                         break;  /* No subobjects for all other types */
 612                 }
 613
 614                 /*
 615                  * Now we can update the count in the main object. This can only
 616                  * happen after we update the sub-objects in case this causes the
 617                  * main object to be deleted.
 618                  */
 619                 acpi_ut_update_ref_count(object, action);
 620                 object = NULL;
 621
 622                 /* Move on to the next object to be updated */
 623
 624                 if (next_object) {
 625                         object = next_object;
 626                         next_object = NULL;
 627                 } else if (state_list) {
 628                         state = acpi_ut_pop_generic_state(&state_list);
 629                         object = state->update.object;
 630                         acpi_ut_delete_generic_state(state);
 631                 }
 632         }
 633
 634         return (AE_OK);
 635
 636 error_exit:
 637
 638         ACPI_EXCEPTION((AE_INFO, status,
 639                         "Could not update object reference count"));
 640
 641         /* Free any stacked Update State objects */
 642
 643         while (state_list) {
 644                 state = acpi_ut_pop_generic_state(&state_list);
 645                 acpi_ut_delete_generic_state(state);
 646         }
 647
 648         return (status);
 649 }
 650
 651 /*******************************************************************************
 652  *
 653  * FUNCTION:    acpi_ut_add_reference
 654  *
 655  * PARAMETERS:  object          - Object whose reference count is to be
 656  *                                incremented
 657  *
 658  * RETURN:      None
 659  *
 660  * DESCRIPTION: Add one reference to an ACPI object
 661  *
 662  ******************************************************************************/
 663
 664 void acpi_ut_add_reference(union acpi_operand_object *object)
 665 {
 666
 667         ACPI_FUNCTION_NAME(ut_add_reference);
 668
 669         /* Ensure that we have a valid object */
 670
 671         if (!acpi_ut_valid_internal_object(object)) {
 672                 return;
 673         }
 674
 675         ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
 676                           "Obj %p Current Refs=%X [To Be Incremented]\n",
 677                           object, object->common.reference_count));
 678
 679         /* Increment the reference count */
 680
 681         (void)acpi_ut_update_object_reference(object, REF_INCREMENT);
 682         return;
 683 }
 684
 685 /*******************************************************************************
 686  *
 687  * FUNCTION:    acpi_ut_remove_reference
 688  *
 689  * PARAMETERS:  object         - Object whose ref count will be decremented
 690  *
 691  * RETURN:      None
 692  *
 693  * DESCRIPTION: Decrement the reference count of an ACPI internal object
 694  *
 695  ******************************************************************************/
 696
 697 void acpi_ut_remove_reference(union acpi_operand_object *object)
 698 {
 699
 700         ACPI_FUNCTION_NAME(ut_remove_reference);
 701
 702         /*
 703          * Allow a NULL pointer to be passed in, just ignore it. This saves
 704          * each caller from having to check. Also, ignore NS nodes.
 705          */
 706         if (!object ||
 707             (ACPI_GET_DESCRIPTOR_TYPE(object) == ACPI_DESC_TYPE_NAMED)) {
 708                 return;
 709         }
 710
 711         /* Ensure that we have a valid object */
 712
 713         if (!acpi_ut_valid_internal_object(object)) {
 714                 return;
 715         }
 716
 717         ACPI_DEBUG_PRINT_RAW((ACPI_DB_ALLOCATIONS,
 718                               "%s: Obj %p Current Refs=%X [To Be Decremented]\n",
 719                               ACPI_GET_FUNCTION_NAME, object,
 720                               object->common.reference_count));
 721
 722         /*
 723          * Decrement the reference count, and only actually delete the object
 724          * if the reference count becomes 0. (Must also decrement the ref count
 725          * of all subobjects!)
 726          */
 727         (void)acpi_ut_update_object_reference(object, REF_DECREMENT);
 728         return;
 729 }