xref: /openbmc/linux/drivers/acpi/acpica/utdelete.c (revision 9cfc5c90)
1 /*******************************************************************************
2  *
3  * Module Name: utdelete - object deletion and reference count utilities
4  *
5  ******************************************************************************/
6 
7 /*
8  * Copyright (C) 2000 - 2015, Intel Corp.
9  * All rights reserved.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions, and the following disclaimer,
16  *    without modification.
17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
18  *    substantially similar to the "NO WARRANTY" disclaimer below
19  *    ("Disclaimer") and any redistribution must be conditioned upon
20  *    including a substantially similar Disclaimer requirement for further
21  *    binary redistribution.
22  * 3. Neither the names of the above-listed copyright holders nor the names
23  *    of any contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * Alternatively, this software may be distributed under the terms of the
27  * GNU General Public License ("GPL") version 2 as published by the Free
28  * Software Foundation.
29  *
30  * NO WARRANTY
31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
41  * POSSIBILITY OF SUCH DAMAGES.
42  */
43 
44 #include <acpi/acpi.h>
45 #include "accommon.h"
46 #include "acinterp.h"
47 #include "acnamesp.h"
48 #include "acevents.h"
49 
50 #define _COMPONENT          ACPI_UTILITIES
51 ACPI_MODULE_NAME("utdelete")
52 
53 /* Local prototypes */
54 static void acpi_ut_delete_internal_obj(union acpi_operand_object *object);
55 
56 static void
57 acpi_ut_update_ref_count(union acpi_operand_object *object, u32 action);
58 
59 /*******************************************************************************
60  *
61  * FUNCTION:    acpi_ut_delete_internal_obj
62  *
63  * PARAMETERS:  object         - Object to be deleted
64  *
65  * RETURN:      None
66  *
67  * DESCRIPTION: Low level object deletion, after reference counts have been
68  *              updated (All reference counts, including sub-objects!)
69  *
70  ******************************************************************************/
71 
72 static void acpi_ut_delete_internal_obj(union acpi_operand_object *object)
73 {
74 	void *obj_pointer = NULL;
75 	union acpi_operand_object *handler_desc;
76 	union acpi_operand_object *second_desc;
77 	union acpi_operand_object *next_desc;
78 	union acpi_operand_object *start_desc;
79 	union acpi_operand_object **last_obj_ptr;
80 
81 	ACPI_FUNCTION_TRACE_PTR(ut_delete_internal_obj, object);
82 
83 	if (!object) {
84 		return_VOID;
85 	}
86 
87 	/*
88 	 * Must delete or free any pointers within the object that are not
89 	 * actual ACPI objects (for example, a raw buffer pointer).
90 	 */
91 	switch (object->common.type) {
92 	case ACPI_TYPE_STRING:
93 
94 		ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
95 				  "**** String %p, ptr %p\n", object,
96 				  object->string.pointer));
97 
98 		/* Free the actual string buffer */
99 
100 		if (!(object->common.flags & AOPOBJ_STATIC_POINTER)) {
101 
102 			/* But only if it is NOT a pointer into an ACPI table */
103 
104 			obj_pointer = object->string.pointer;
105 		}
106 		break;
107 
108 	case ACPI_TYPE_BUFFER:
109 
110 		ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
111 				  "**** Buffer %p, ptr %p\n", object,
112 				  object->buffer.pointer));
113 
114 		/* Free the actual buffer */
115 
116 		if (!(object->common.flags & AOPOBJ_STATIC_POINTER)) {
117 
118 			/* But only if it is NOT a pointer into an ACPI table */
119 
120 			obj_pointer = object->buffer.pointer;
121 		}
122 		break;
123 
124 	case ACPI_TYPE_PACKAGE:
125 
126 		ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
127 				  " **** Package of count %X\n",
128 				  object->package.count));
129 
130 		/*
131 		 * Elements of the package are not handled here, they are deleted
132 		 * separately
133 		 */
134 
135 		/* Free the (variable length) element pointer array */
136 
137 		obj_pointer = object->package.elements;
138 		break;
139 
140 		/*
141 		 * These objects have a possible list of notify handlers.
142 		 * Device object also may have a GPE block.
143 		 */
144 	case ACPI_TYPE_DEVICE:
145 
146 		if (object->device.gpe_block) {
147 			(void)acpi_ev_delete_gpe_block(object->device.
148 						       gpe_block);
149 		}
150 
151 		/*lint -fallthrough */
152 
153 	case ACPI_TYPE_PROCESSOR:
154 	case ACPI_TYPE_THERMAL:
155 
156 		/* Walk the address handler list for this object */
157 
158 		handler_desc = object->common_notify.handler;
159 		while (handler_desc) {
160 			next_desc = handler_desc->address_space.next;
161 			acpi_ut_remove_reference(handler_desc);
162 			handler_desc = next_desc;
163 		}
164 		break;
165 
166 	case ACPI_TYPE_MUTEX:
167 
168 		ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
169 				  "***** Mutex %p, OS Mutex %p\n",
170 				  object, object->mutex.os_mutex));
171 
172 		if (object == acpi_gbl_global_lock_mutex) {
173 
174 			/* Global Lock has extra semaphore */
175 
176 			(void)
177 			    acpi_os_delete_semaphore
178 			    (acpi_gbl_global_lock_semaphore);
179 			acpi_gbl_global_lock_semaphore = NULL;
180 
181 			acpi_os_delete_mutex(object->mutex.os_mutex);
182 			acpi_gbl_global_lock_mutex = NULL;
183 		} else {
184 			acpi_ex_unlink_mutex(object);
185 			acpi_os_delete_mutex(object->mutex.os_mutex);
186 		}
187 		break;
188 
189 	case ACPI_TYPE_EVENT:
190 
191 		ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
192 				  "***** Event %p, OS Semaphore %p\n",
193 				  object, object->event.os_semaphore));
194 
195 		(void)acpi_os_delete_semaphore(object->event.os_semaphore);
196 		object->event.os_semaphore = NULL;
197 		break;
198 
199 	case ACPI_TYPE_METHOD:
200 
201 		ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
202 				  "***** Method %p\n", object));
203 
204 		/* Delete the method mutex if it exists */
205 
206 		if (object->method.mutex) {
207 			acpi_os_delete_mutex(object->method.mutex->mutex.
208 					     os_mutex);
209 			acpi_ut_delete_object_desc(object->method.mutex);
210 			object->method.mutex = NULL;
211 		}
212 		if (object->method.node) {
213 			object->method.node = NULL;
214 		}
215 		break;
216 
217 	case ACPI_TYPE_REGION:
218 
219 		ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
220 				  "***** Region %p\n", object));
221 
222 		/*
223 		 * Update address_range list. However, only permanent regions
224 		 * are installed in this list. (Not created within a method)
225 		 */
226 		if (!(object->region.node->flags & ANOBJ_TEMPORARY)) {
227 			acpi_ut_remove_address_range(object->region.space_id,
228 						     object->region.node);
229 		}
230 
231 		second_desc = acpi_ns_get_secondary_object(object);
232 		if (second_desc) {
233 			/*
234 			 * Free the region_context if and only if the handler is one of the
235 			 * default handlers -- and therefore, we created the context object
236 			 * locally, it was not created by an external caller.
237 			 */
238 			handler_desc = object->region.handler;
239 			if (handler_desc) {
240 				next_desc =
241 				    handler_desc->address_space.region_list;
242 				start_desc = next_desc;
243 				last_obj_ptr =
244 				    &handler_desc->address_space.region_list;
245 
246 				/* Remove the region object from the handler list */
247 
248 				while (next_desc) {
249 					if (next_desc == object) {
250 						*last_obj_ptr =
251 						    next_desc->region.next;
252 						break;
253 					}
254 
255 					/* Walk the linked list of handlers */
256 
257 					last_obj_ptr = &next_desc->region.next;
258 					next_desc = next_desc->region.next;
259 
260 					/* Prevent infinite loop if list is corrupted */
261 
262 					if (next_desc == start_desc) {
263 						ACPI_ERROR((AE_INFO,
264 							    "Circular region list in address handler object %p",
265 							    handler_desc));
266 						return_VOID;
267 					}
268 				}
269 
270 				if (handler_desc->address_space.handler_flags &
271 				    ACPI_ADDR_HANDLER_DEFAULT_INSTALLED) {
272 
273 					/* Deactivate region and free region context */
274 
275 					if (handler_desc->address_space.setup) {
276 						(void)handler_desc->
277 						    address_space.setup(object,
278 									ACPI_REGION_DEACTIVATE,
279 									handler_desc->
280 									address_space.
281 									context,
282 									&second_desc->
283 									extra.
284 									region_context);
285 					}
286 				}
287 
288 				acpi_ut_remove_reference(handler_desc);
289 			}
290 
291 			/* Now we can free the Extra object */
292 
293 			acpi_ut_delete_object_desc(second_desc);
294 		}
295 		break;
296 
297 	case ACPI_TYPE_BUFFER_FIELD:
298 
299 		ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
300 				  "***** Buffer Field %p\n", object));
301 
302 		second_desc = acpi_ns_get_secondary_object(object);
303 		if (second_desc) {
304 			acpi_ut_delete_object_desc(second_desc);
305 		}
306 		break;
307 
308 	case ACPI_TYPE_LOCAL_BANK_FIELD:
309 
310 		ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
311 				  "***** Bank Field %p\n", object));
312 
313 		second_desc = acpi_ns_get_secondary_object(object);
314 		if (second_desc) {
315 			acpi_ut_delete_object_desc(second_desc);
316 		}
317 		break;
318 
319 	default:
320 
321 		break;
322 	}
323 
324 	/* Free any allocated memory (pointer within the object) found above */
325 
326 	if (obj_pointer) {
327 		ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
328 				  "Deleting Object Subptr %p\n", obj_pointer));
329 		ACPI_FREE(obj_pointer);
330 	}
331 
332 	/* Now the object can be safely deleted */
333 
334 	ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS, "Deleting Object %p [%s]\n",
335 			  object, acpi_ut_get_object_type_name(object)));
336 
337 	acpi_ut_delete_object_desc(object);
338 	return_VOID;
339 }
340 
341 /*******************************************************************************
342  *
343  * FUNCTION:    acpi_ut_delete_internal_object_list
344  *
345  * PARAMETERS:  obj_list        - Pointer to the list to be deleted
346  *
347  * RETURN:      None
348  *
349  * DESCRIPTION: This function deletes an internal object list, including both
350  *              simple objects and package objects
351  *
352  ******************************************************************************/
353 
354 void acpi_ut_delete_internal_object_list(union acpi_operand_object **obj_list)
355 {
356 	union acpi_operand_object **internal_obj;
357 
358 	ACPI_FUNCTION_ENTRY();
359 
360 	/* Walk the null-terminated internal list */
361 
362 	for (internal_obj = obj_list; *internal_obj; internal_obj++) {
363 		acpi_ut_remove_reference(*internal_obj);
364 	}
365 
366 	/* Free the combined parameter pointer list and object array */
367 
368 	ACPI_FREE(obj_list);
369 	return;
370 }
371 
372 /*******************************************************************************
373  *
374  * FUNCTION:    acpi_ut_update_ref_count
375  *
376  * PARAMETERS:  object          - Object whose ref count is to be updated
377  *              action          - What to do (REF_INCREMENT or REF_DECREMENT)
378  *
379  * RETURN:      None. Sets new reference count within the object
380  *
381  * DESCRIPTION: Modify the reference count for an internal acpi object
382  *
383  ******************************************************************************/
384 
385 static void
386 acpi_ut_update_ref_count(union acpi_operand_object *object, u32 action)
387 {
388 	u16 original_count;
389 	u16 new_count = 0;
390 	acpi_cpu_flags lock_flags;
391 
392 	ACPI_FUNCTION_NAME(ut_update_ref_count);
393 
394 	if (!object) {
395 		return;
396 	}
397 
398 	/*
399 	 * Always get the reference count lock. Note: Interpreter and/or
400 	 * Namespace is not always locked when this function is called.
401 	 */
402 	lock_flags = acpi_os_acquire_lock(acpi_gbl_reference_count_lock);
403 	original_count = object->common.reference_count;
404 
405 	/* Perform the reference count action (increment, decrement) */
406 
407 	switch (action) {
408 	case REF_INCREMENT:
409 
410 		new_count = original_count + 1;
411 		object->common.reference_count = new_count;
412 		acpi_os_release_lock(acpi_gbl_reference_count_lock, lock_flags);
413 
414 		/* The current reference count should never be zero here */
415 
416 		if (!original_count) {
417 			ACPI_WARNING((AE_INFO,
418 				      "Obj %p, Reference Count was zero before increment\n",
419 				      object));
420 		}
421 
422 		ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
423 				  "Obj %p Type %.2X Refs %.2X [Incremented]\n",
424 				  object, object->common.type, new_count));
425 		break;
426 
427 	case REF_DECREMENT:
428 
429 		/* The current reference count must be non-zero */
430 
431 		if (original_count) {
432 			new_count = original_count - 1;
433 			object->common.reference_count = new_count;
434 		}
435 
436 		acpi_os_release_lock(acpi_gbl_reference_count_lock, lock_flags);
437 
438 		if (!original_count) {
439 			ACPI_WARNING((AE_INFO,
440 				      "Obj %p, Reference Count is already zero, cannot decrement\n",
441 				      object));
442 		}
443 
444 		ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
445 				  "Obj %p Type %.2X Refs %.2X [Decremented]\n",
446 				  object, object->common.type, new_count));
447 
448 		/* Actually delete the object on a reference count of zero */
449 
450 		if (new_count == 0) {
451 			acpi_ut_delete_internal_obj(object);
452 		}
453 		break;
454 
455 	default:
456 
457 		acpi_os_release_lock(acpi_gbl_reference_count_lock, lock_flags);
458 		ACPI_ERROR((AE_INFO, "Unknown Reference Count action (0x%X)",
459 			    action));
460 		return;
461 	}
462 
463 	/*
464 	 * Sanity check the reference count, for debug purposes only.
465 	 * (A deleted object will have a huge reference count)
466 	 */
467 	if (new_count > ACPI_MAX_REFERENCE_COUNT) {
468 		ACPI_WARNING((AE_INFO,
469 			      "Large Reference Count (0x%X) in object %p, Type=0x%.2X",
470 			      new_count, object, object->common.type));
471 	}
472 }
473 
474 /*******************************************************************************
475  *
476  * FUNCTION:    acpi_ut_update_object_reference
477  *
478  * PARAMETERS:  object              - Increment ref count for this object
479  *                                    and all sub-objects
480  *              action              - Either REF_INCREMENT or REF_DECREMENT
481  *
482  * RETURN:      Status
483  *
484  * DESCRIPTION: Increment the object reference count
485  *
486  * Object references are incremented when:
487  * 1) An object is attached to a Node (namespace object)
488  * 2) An object is copied (all subobjects must be incremented)
489  *
490  * Object references are decremented when:
491  * 1) An object is detached from an Node
492  *
493  ******************************************************************************/
494 
495 acpi_status
496 acpi_ut_update_object_reference(union acpi_operand_object *object, u16 action)
497 {
498 	acpi_status status = AE_OK;
499 	union acpi_generic_state *state_list = NULL;
500 	union acpi_operand_object *next_object = NULL;
501 	union acpi_operand_object *prev_object;
502 	union acpi_generic_state *state;
503 	u32 i;
504 
505 	ACPI_FUNCTION_NAME(ut_update_object_reference);
506 
507 	while (object) {
508 
509 		/* Make sure that this isn't a namespace handle */
510 
511 		if (ACPI_GET_DESCRIPTOR_TYPE(object) == ACPI_DESC_TYPE_NAMED) {
512 			ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
513 					  "Object %p is NS handle\n", object));
514 			return (AE_OK);
515 		}
516 
517 		/*
518 		 * All sub-objects must have their reference count incremented also.
519 		 * Different object types have different subobjects.
520 		 */
521 		switch (object->common.type) {
522 		case ACPI_TYPE_DEVICE:
523 		case ACPI_TYPE_PROCESSOR:
524 		case ACPI_TYPE_POWER:
525 		case ACPI_TYPE_THERMAL:
526 			/*
527 			 * Update the notify objects for these types (if present)
528 			 * Two lists, system and device notify handlers.
529 			 */
530 			for (i = 0; i < ACPI_NUM_NOTIFY_TYPES; i++) {
531 				prev_object =
532 				    object->common_notify.notify_list[i];
533 				while (prev_object) {
534 					next_object =
535 					    prev_object->notify.next[i];
536 					acpi_ut_update_ref_count(prev_object,
537 								 action);
538 					prev_object = next_object;
539 				}
540 			}
541 			break;
542 
543 		case ACPI_TYPE_PACKAGE:
544 			/*
545 			 * We must update all the sub-objects of the package,
546 			 * each of whom may have their own sub-objects.
547 			 */
548 			for (i = 0; i < object->package.count; i++) {
549 				/*
550 				 * Null package elements are legal and can be simply
551 				 * ignored.
552 				 */
553 				next_object = object->package.elements[i];
554 				if (!next_object) {
555 					continue;
556 				}
557 
558 				switch (next_object->common.type) {
559 				case ACPI_TYPE_INTEGER:
560 				case ACPI_TYPE_STRING:
561 				case ACPI_TYPE_BUFFER:
562 					/*
563 					 * For these very simple sub-objects, we can just
564 					 * update the reference count here and continue.
565 					 * Greatly increases performance of this operation.
566 					 */
567 					acpi_ut_update_ref_count(next_object,
568 								 action);
569 					break;
570 
571 				default:
572 					/*
573 					 * For complex sub-objects, push them onto the stack
574 					 * for later processing (this eliminates recursion.)
575 					 */
576 					status =
577 					    acpi_ut_create_update_state_and_push
578 					    (next_object, action, &state_list);
579 					if (ACPI_FAILURE(status)) {
580 						goto error_exit;
581 					}
582 					break;
583 				}
584 			}
585 			next_object = NULL;
586 			break;
587 
588 		case ACPI_TYPE_BUFFER_FIELD:
589 
590 			next_object = object->buffer_field.buffer_obj;
591 			break;
592 
593 		case ACPI_TYPE_LOCAL_REGION_FIELD:
594 
595 			next_object = object->field.region_obj;
596 			break;
597 
598 		case ACPI_TYPE_LOCAL_BANK_FIELD:
599 
600 			next_object = object->bank_field.bank_obj;
601 			status =
602 			    acpi_ut_create_update_state_and_push(object->
603 								 bank_field.
604 								 region_obj,
605 								 action,
606 								 &state_list);
607 			if (ACPI_FAILURE(status)) {
608 				goto error_exit;
609 			}
610 			break;
611 
612 		case ACPI_TYPE_LOCAL_INDEX_FIELD:
613 
614 			next_object = object->index_field.index_obj;
615 			status =
616 			    acpi_ut_create_update_state_and_push(object->
617 								 index_field.
618 								 data_obj,
619 								 action,
620 								 &state_list);
621 			if (ACPI_FAILURE(status)) {
622 				goto error_exit;
623 			}
624 			break;
625 
626 		case ACPI_TYPE_LOCAL_REFERENCE:
627 			/*
628 			 * The target of an Index (a package, string, or buffer) or a named
629 			 * reference must track changes to the ref count of the index or
630 			 * target object.
631 			 */
632 			if ((object->reference.class == ACPI_REFCLASS_INDEX) ||
633 			    (object->reference.class == ACPI_REFCLASS_NAME)) {
634 				next_object = object->reference.object;
635 			}
636 			break;
637 
638 		case ACPI_TYPE_REGION:
639 		default:
640 
641 			break;	/* No subobjects for all other types */
642 		}
643 
644 		/*
645 		 * Now we can update the count in the main object. This can only
646 		 * happen after we update the sub-objects in case this causes the
647 		 * main object to be deleted.
648 		 */
649 		acpi_ut_update_ref_count(object, action);
650 		object = NULL;
651 
652 		/* Move on to the next object to be updated */
653 
654 		if (next_object) {
655 			object = next_object;
656 			next_object = NULL;
657 		} else if (state_list) {
658 			state = acpi_ut_pop_generic_state(&state_list);
659 			object = state->update.object;
660 			acpi_ut_delete_generic_state(state);
661 		}
662 	}
663 
664 	return (AE_OK);
665 
666 error_exit:
667 
668 	ACPI_EXCEPTION((AE_INFO, status,
669 			"Could not update object reference count"));
670 
671 	/* Free any stacked Update State objects */
672 
673 	while (state_list) {
674 		state = acpi_ut_pop_generic_state(&state_list);
675 		acpi_ut_delete_generic_state(state);
676 	}
677 
678 	return (status);
679 }
680 
681 /*******************************************************************************
682  *
683  * FUNCTION:    acpi_ut_add_reference
684  *
685  * PARAMETERS:  object          - Object whose reference count is to be
686  *                                incremented
687  *
688  * RETURN:      None
689  *
690  * DESCRIPTION: Add one reference to an ACPI object
691  *
692  ******************************************************************************/
693 
694 void acpi_ut_add_reference(union acpi_operand_object *object)
695 {
696 
697 	ACPI_FUNCTION_NAME(ut_add_reference);
698 
699 	/* Ensure that we have a valid object */
700 
701 	if (!acpi_ut_valid_internal_object(object)) {
702 		return;
703 	}
704 
705 	ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
706 			  "Obj %p Current Refs=%X [To Be Incremented]\n",
707 			  object, object->common.reference_count));
708 
709 	/* Increment the reference count */
710 
711 	(void)acpi_ut_update_object_reference(object, REF_INCREMENT);
712 	return;
713 }
714 
715 /*******************************************************************************
716  *
717  * FUNCTION:    acpi_ut_remove_reference
718  *
719  * PARAMETERS:  object         - Object whose ref count will be decremented
720  *
721  * RETURN:      None
722  *
723  * DESCRIPTION: Decrement the reference count of an ACPI internal object
724  *
725  ******************************************************************************/
726 
727 void acpi_ut_remove_reference(union acpi_operand_object *object)
728 {
729 
730 	ACPI_FUNCTION_NAME(ut_remove_reference);
731 
732 	/*
733 	 * Allow a NULL pointer to be passed in, just ignore it. This saves
734 	 * each caller from having to check. Also, ignore NS nodes.
735 	 */
736 	if (!object ||
737 	    (ACPI_GET_DESCRIPTOR_TYPE(object) == ACPI_DESC_TYPE_NAMED)) {
738 		return;
739 	}
740 
741 	/* Ensure that we have a valid object */
742 
743 	if (!acpi_ut_valid_internal_object(object)) {
744 		return;
745 	}
746 
747 	ACPI_DEBUG_PRINT((ACPI_DB_ALLOCATIONS,
748 			  "Obj %p Current Refs=%X [To Be Decremented]\n",
749 			  object, object->common.reference_count));
750 
751 	/*
752 	 * Decrement the reference count, and only actually delete the object
753 	 * if the reference count becomes 0. (Must also decrement the ref count
754 	 * of all subobjects!)
755 	 */
756 	(void)acpi_ut_update_object_reference(object, REF_DECREMENT);
757 	return;
758 }
759