Home | History | Annotate | Line # | Download | only in namespace
      1 /*******************************************************************************
      2  *
      3  * Module Name: nsalloc - Namespace allocation and deletion utilities
      4  *
      5  ******************************************************************************/
      6 
      7 /******************************************************************************
      8  *
      9  * 1. Copyright Notice
     10  *
     11  * Some or all of this work - Copyright (c) 1999 - 2025, Intel Corp.
     12  * All rights reserved.
     13  *
     14  * 2. License
     15  *
     16  * 2.1. This is your license from Intel Corp. under its intellectual property
     17  * rights. You may have additional license terms from the party that provided
     18  * you this software, covering your right to use that party's intellectual
     19  * property rights.
     20  *
     21  * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
     22  * copy of the source code appearing in this file ("Covered Code") an
     23  * irrevocable, perpetual, worldwide license under Intel's copyrights in the
     24  * base code distributed originally by Intel ("Original Intel Code") to copy,
     25  * make derivatives, distribute, use and display any portion of the Covered
     26  * Code in any form, with the right to sublicense such rights; and
     27  *
     28  * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
     29  * license (with the right to sublicense), under only those claims of Intel
     30  * patents that are infringed by the Original Intel Code, to make, use, sell,
     31  * offer to sell, and import the Covered Code and derivative works thereof
     32  * solely to the minimum extent necessary to exercise the above copyright
     33  * license, and in no event shall the patent license extend to any additions
     34  * to or modifications of the Original Intel Code. No other license or right
     35  * is granted directly or by implication, estoppel or otherwise;
     36  *
     37  * The above copyright and patent license is granted only if the following
     38  * conditions are met:
     39  *
     40  * 3. Conditions
     41  *
     42  * 3.1. Redistribution of Source with Rights to Further Distribute Source.
     43  * Redistribution of source code of any substantial portion of the Covered
     44  * Code or modification with rights to further distribute source must include
     45  * the above Copyright Notice, the above License, this list of Conditions,
     46  * and the following Disclaimer and Export Compliance provision. In addition,
     47  * Licensee must cause all Covered Code to which Licensee contributes to
     48  * contain a file documenting the changes Licensee made to create that Covered
     49  * Code and the date of any change. Licensee must include in that file the
     50  * documentation of any changes made by any predecessor Licensee. Licensee
     51  * must include a prominent statement that the modification is derived,
     52  * directly or indirectly, from Original Intel Code.
     53  *
     54  * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
     55  * Redistribution of source code of any substantial portion of the Covered
     56  * Code or modification without rights to further distribute source must
     57  * include the following Disclaimer and Export Compliance provision in the
     58  * documentation and/or other materials provided with distribution. In
     59  * addition, Licensee may not authorize further sublicense of source of any
     60  * portion of the Covered Code, and must include terms to the effect that the
     61  * license from Licensee to its licensee is limited to the intellectual
     62  * property embodied in the software Licensee provides to its licensee, and
     63  * not to intellectual property embodied in modifications its licensee may
     64  * make.
     65  *
     66  * 3.3. Redistribution of Executable. Redistribution in executable form of any
     67  * substantial portion of the Covered Code or modification must reproduce the
     68  * above Copyright Notice, and the following Disclaimer and Export Compliance
     69  * provision in the documentation and/or other materials provided with the
     70  * distribution.
     71  *
     72  * 3.4. Intel retains all right, title, and interest in and to the Original
     73  * Intel Code.
     74  *
     75  * 3.5. Neither the name Intel nor any other trademark owned or controlled by
     76  * Intel shall be used in advertising or otherwise to promote the sale, use or
     77  * other dealings in products derived from or relating to the Covered Code
     78  * without prior written authorization from Intel.
     79  *
     80  * 4. Disclaimer and Export Compliance
     81  *
     82  * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
     83  * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
     84  * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE,
     85  * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY
     86  * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY
     87  * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
     88  * PARTICULAR PURPOSE.
     89  *
     90  * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
     91  * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
     92  * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
     93  * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
     94  * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
     95  * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS
     96  * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
     97  * LIMITED REMEDY.
     98  *
     99  * 4.3. Licensee shall not export, either directly or indirectly, any of this
    100  * software or system incorporating such software without first obtaining any
    101  * required license or other approval from the U. S. Department of Commerce or
    102  * any other agency or department of the United States Government. In the
    103  * event Licensee exports any such software from the United States or
    104  * re-exports any such software from a foreign destination, Licensee shall
    105  * ensure that the distribution and export/re-export of the software is in
    106  * compliance with all laws, regulations, orders, or other restrictions of the
    107  * U.S. Export Administration Regulations. Licensee agrees that neither it nor
    108  * any of its subsidiaries will export/re-export any technical data, process,
    109  * software, or service, directly or indirectly, to any country for which the
    110  * United States government or any agency thereof requires an export license,
    111  * other governmental approval, or letter of assurance, without first obtaining
    112  * such license, approval or letter.
    113  *
    114  *****************************************************************************
    115  *
    116  * Alternatively, you may choose to be licensed under the terms of the
    117  * following license:
    118  *
    119  * Redistribution and use in source and binary forms, with or without
    120  * modification, are permitted provided that the following conditions
    121  * are met:
    122  * 1. Redistributions of source code must retain the above copyright
    123  *    notice, this list of conditions, and the following disclaimer,
    124  *    without modification.
    125  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
    126  *    substantially similar to the "NO WARRANTY" disclaimer below
    127  *    ("Disclaimer") and any redistribution must be conditioned upon
    128  *    including a substantially similar Disclaimer requirement for further
    129  *    binary redistribution.
    130  * 3. Neither the names of the above-listed copyright holders nor the names
    131  *    of any contributors may be used to endorse or promote products derived
    132  *    from this software without specific prior written permission.
    133  *
    134  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    135  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    136  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    137  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    138  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    139  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    140  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    141  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    142  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    143  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    144  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    145  *
    146  * Alternatively, you may choose to be licensed under the terms of the
    147  * GNU General Public License ("GPL") version 2 as published by the Free
    148  * Software Foundation.
    149  *
    150  *****************************************************************************/
    151 
    152 #include "acpi.h"
    153 #include "accommon.h"
    154 #include "acnamesp.h"
    155 
    156 
    157 #define _COMPONENT          ACPI_NAMESPACE
    158         ACPI_MODULE_NAME    ("nsalloc")
    159 
    160 
    161 /*******************************************************************************
    162  *
    163  * FUNCTION:    AcpiNsCreateNode
    164  *
    165  * PARAMETERS:  Name            - Name of the new node (4 char ACPI name)
    166  *
    167  * RETURN:      New namespace node (Null on failure)
    168  *
    169  * DESCRIPTION: Create a namespace node
    170  *
    171  ******************************************************************************/
    172 
    173 ACPI_NAMESPACE_NODE *
    174 AcpiNsCreateNode (
    175     UINT32                  Name)
    176 {
    177     ACPI_NAMESPACE_NODE     *Node;
    178 #ifdef ACPI_DBG_TRACK_ALLOCATIONS
    179     UINT32                  Temp;
    180 #endif
    181 
    182 
    183     ACPI_FUNCTION_TRACE (NsCreateNode);
    184 
    185 
    186     Node = AcpiOsAcquireObject (AcpiGbl_NamespaceCache);
    187     if (!Node)
    188     {
    189         return_PTR (NULL);
    190     }
    191 
    192     ACPI_MEM_TRACKING (AcpiGbl_NsNodeList->TotalAllocated++);
    193 
    194 #ifdef ACPI_DBG_TRACK_ALLOCATIONS
    195         Temp = AcpiGbl_NsNodeList->TotalAllocated -
    196             AcpiGbl_NsNodeList->TotalFreed;
    197         if (Temp > AcpiGbl_NsNodeList->MaxOccupied)
    198         {
    199             AcpiGbl_NsNodeList->MaxOccupied = Temp;
    200         }
    201 #endif
    202 
    203     Node->Name.Integer = Name;
    204     ACPI_SET_DESCRIPTOR_TYPE (Node, ACPI_DESC_TYPE_NAMED);
    205     return_PTR (Node);
    206 }
    207 
    208 
    209 /*******************************************************************************
    210  *
    211  * FUNCTION:    AcpiNsDeleteNode
    212  *
    213  * PARAMETERS:  Node            - Node to be deleted
    214  *
    215  * RETURN:      None
    216  *
    217  * DESCRIPTION: Delete a namespace node. All node deletions must come through
    218  *              here. Detaches any attached objects, including any attached
    219  *              data. If a handler is associated with attached data, it is
    220  *              invoked before the node is deleted.
    221  *
    222  ******************************************************************************/
    223 
    224 void
    225 AcpiNsDeleteNode (
    226     ACPI_NAMESPACE_NODE     *Node)
    227 {
    228     ACPI_OPERAND_OBJECT     *ObjDesc;
    229     ACPI_OPERAND_OBJECT     *NextDesc;
    230 
    231 
    232     ACPI_FUNCTION_NAME (NsDeleteNode);
    233 
    234 
    235     if (!Node)
    236     {
    237         return_VOID;
    238     }
    239 
    240     /* Detach an object if there is one */
    241 
    242     AcpiNsDetachObject (Node);
    243 
    244     /*
    245      * Delete an attached data object list if present (objects that were
    246      * attached via AcpiAttachData). Note: After any normal object is
    247      * detached above, the only possible remaining object(s) are data
    248      * objects, in a linked list.
    249      */
    250     ObjDesc = Node->Object;
    251     while (ObjDesc &&
    252         (ObjDesc->Common.Type == ACPI_TYPE_LOCAL_DATA))
    253     {
    254         /* Invoke the attached data deletion handler if present */
    255 
    256         if (ObjDesc->Data.Handler)
    257         {
    258             ObjDesc->Data.Handler (Node, ObjDesc->Data.Pointer);
    259         }
    260 
    261         NextDesc = ObjDesc->Common.NextObject;
    262         AcpiUtRemoveReference (ObjDesc);
    263         ObjDesc = NextDesc;
    264     }
    265 
    266     /* Special case for the statically allocated root node */
    267 
    268     if (Node == AcpiGbl_RootNode)
    269     {
    270         return;
    271     }
    272 
    273     /* Now we can delete the node */
    274 
    275     (void) AcpiOsReleaseObject (AcpiGbl_NamespaceCache, Node);
    276 
    277     ACPI_MEM_TRACKING (AcpiGbl_NsNodeList->TotalFreed++);
    278     ACPI_DEBUG_PRINT ((ACPI_DB_ALLOCATIONS, "Node %p, Remaining %X\n",
    279         Node, AcpiGbl_CurrentNodeCount));
    280 }
    281 
    282 
    283 /*******************************************************************************
    284  *
    285  * FUNCTION:    AcpiNsRemoveNode
    286  *
    287  * PARAMETERS:  Node            - Node to be removed/deleted
    288  *
    289  * RETURN:      None
    290  *
    291  * DESCRIPTION: Remove (unlink) and delete a namespace node
    292  *
    293  ******************************************************************************/
    294 
    295 void
    296 AcpiNsRemoveNode (
    297     ACPI_NAMESPACE_NODE     *Node)
    298 {
    299     ACPI_NAMESPACE_NODE     *ParentNode;
    300     ACPI_NAMESPACE_NODE     *PrevNode;
    301     ACPI_NAMESPACE_NODE     *NextNode;
    302 
    303 
    304     ACPI_FUNCTION_TRACE_PTR (NsRemoveNode, Node);
    305 
    306 
    307     ParentNode = Node->Parent;
    308 
    309     PrevNode = NULL;
    310     NextNode = ParentNode->Child;
    311 
    312     /* Find the node that is the previous peer in the parent's child list */
    313 
    314     while (NextNode != Node)
    315     {
    316         PrevNode = NextNode;
    317         NextNode = NextNode->Peer;
    318     }
    319 
    320     if (PrevNode)
    321     {
    322         /* Node is not first child, unlink it */
    323 
    324         PrevNode->Peer = Node->Peer;
    325     }
    326     else
    327     {
    328         /*
    329          * Node is first child (has no previous peer).
    330          * Link peer list to parent
    331          */
    332         ParentNode->Child = Node->Peer;
    333     }
    334 
    335     /* Delete the node and any attached objects */
    336 
    337     AcpiNsDeleteNode (Node);
    338     return_VOID;
    339 }
    340 
    341 
    342 /*******************************************************************************
    343  *
    344  * FUNCTION:    AcpiNsInstallNode
    345  *
    346  * PARAMETERS:  WalkState       - Current state of the walk
    347  *              ParentNode      - The parent of the new Node
    348  *              Node            - The new Node to install
    349  *              Type            - ACPI object type of the new Node
    350  *
    351  * RETURN:      None
    352  *
    353  * DESCRIPTION: Initialize a new namespace node and install it amongst
    354  *              its peers.
    355  *
    356  *              Note: Current namespace lookup is linear search. This appears
    357  *              to be sufficient as namespace searches consume only a small
    358  *              fraction of the execution time of the ACPI subsystem.
    359  *
    360  ******************************************************************************/
    361 
    362 void
    363 AcpiNsInstallNode (
    364     ACPI_WALK_STATE         *WalkState,
    365     ACPI_NAMESPACE_NODE     *ParentNode,    /* Parent */
    366     ACPI_NAMESPACE_NODE     *Node,          /* New Child*/
    367     ACPI_OBJECT_TYPE        Type)
    368 {
    369     ACPI_OWNER_ID           OwnerId = 0;
    370     ACPI_NAMESPACE_NODE     *ChildNode;
    371 
    372 
    373     ACPI_FUNCTION_TRACE (NsInstallNode);
    374 
    375 
    376     if (WalkState)
    377     {
    378         /*
    379          * Get the owner ID from the Walk state. The owner ID is used to
    380          * track table deletion and deletion of objects created by methods.
    381          */
    382         OwnerId = WalkState->OwnerId;
    383 
    384         if ((WalkState->MethodDesc) &&
    385             (ParentNode != WalkState->MethodNode))
    386         {
    387             /*
    388              * A method is creating a new node that is not a child of the
    389              * method (it is non-local). Mark the executing method as having
    390              * modified the namespace. This is used for cleanup when the
    391              * method exits.
    392              */
    393             WalkState->MethodDesc->Method.InfoFlags |=
    394                 ACPI_METHOD_MODIFIED_NAMESPACE;
    395         }
    396     }
    397 
    398     /* Link the new entry into the parent and existing children */
    399 
    400     Node->Peer = NULL;
    401     Node->Parent = ParentNode;
    402     ChildNode = ParentNode->Child;
    403 
    404     if (!ChildNode)
    405     {
    406         ParentNode->Child = Node;
    407     }
    408     else
    409     {
    410         /* Add node to the end of the peer list */
    411 
    412         while (ChildNode->Peer)
    413         {
    414             ChildNode = ChildNode->Peer;
    415         }
    416 
    417         ChildNode->Peer = Node;
    418     }
    419 
    420     /* Init the new entry */
    421 
    422     Node->OwnerId = OwnerId;
    423     Node->Type = (UINT8) Type;
    424 
    425     ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
    426         "%4.4s (%s) [Node %p Owner %3.3X] added to %4.4s (%s) [Node %p]\n",
    427         AcpiUtGetNodeName (Node), AcpiUtGetTypeName (Node->Type), Node, OwnerId,
    428         AcpiUtGetNodeName (ParentNode), AcpiUtGetTypeName (ParentNode->Type),
    429         ParentNode));
    430 
    431     return_VOID;
    432 }
    433 
    434 
    435 /*******************************************************************************
    436  *
    437  * FUNCTION:    AcpiNsDeleteChildren
    438  *
    439  * PARAMETERS:  ParentNode      - Delete this objects children
    440  *
    441  * RETURN:      None.
    442  *
    443  * DESCRIPTION: Delete all children of the parent object. In other words,
    444  *              deletes a "scope".
    445  *
    446  ******************************************************************************/
    447 
    448 void
    449 AcpiNsDeleteChildren (
    450     ACPI_NAMESPACE_NODE     *ParentNode)
    451 {
    452     ACPI_NAMESPACE_NODE     *NextNode;
    453     ACPI_NAMESPACE_NODE     *NodeToDelete;
    454 
    455 
    456     ACPI_FUNCTION_TRACE_PTR (NsDeleteChildren, ParentNode);
    457 
    458 
    459     if (!ParentNode)
    460     {
    461         return_VOID;
    462     }
    463 
    464     /* Deallocate all children at this level */
    465 
    466     NextNode = ParentNode->Child;
    467     while (NextNode)
    468     {
    469         /* Grandchildren should have all been deleted already */
    470 
    471         if (NextNode->Child)
    472         {
    473             ACPI_ERROR ((AE_INFO, "Found a grandchild! P=%p C=%p",
    474                 ParentNode, NextNode));
    475         }
    476 
    477         /*
    478          * Delete this child node and move on to the next child in the list.
    479          * No need to unlink the node since we are deleting the entire branch.
    480          */
    481         NodeToDelete = NextNode;
    482         NextNode = NextNode->Peer;
    483         AcpiNsDeleteNode (NodeToDelete);
    484     }
    485 
    486     /* Clear the parent's child pointer */
    487 
    488     ParentNode->Child = NULL;
    489     return_VOID;
    490 }
    491 
    492 
    493 /*******************************************************************************
    494  *
    495  * FUNCTION:    AcpiNsDeleteNamespaceSubtree
    496  *
    497  * PARAMETERS:  ParentNode      - Root of the subtree to be deleted
    498  *
    499  * RETURN:      None.
    500  *
    501  * DESCRIPTION: Delete a subtree of the namespace. This includes all objects
    502  *              stored within the subtree.
    503  *
    504  ******************************************************************************/
    505 
    506 void
    507 AcpiNsDeleteNamespaceSubtree (
    508     ACPI_NAMESPACE_NODE     *ParentNode)
    509 {
    510     ACPI_NAMESPACE_NODE     *ChildNode = NULL;
    511     UINT32                  Level = 1;
    512     ACPI_STATUS             Status;
    513 
    514 
    515     ACPI_FUNCTION_TRACE (NsDeleteNamespaceSubtree);
    516 
    517 
    518     if (!ParentNode)
    519     {
    520         return_VOID;
    521     }
    522 
    523     /* Lock namespace for possible update */
    524 
    525     Status = AcpiUtAcquireMutex (ACPI_MTX_NAMESPACE);
    526     if (ACPI_FAILURE (Status))
    527     {
    528         return_VOID;
    529     }
    530 
    531     /*
    532      * Traverse the tree of objects until we bubble back up
    533      * to where we started.
    534      */
    535     while (Level > 0)
    536     {
    537         /* Get the next node in this scope (NULL if none) */
    538 
    539         ChildNode = AcpiNsGetNextNode (ParentNode, ChildNode);
    540         if (ChildNode)
    541         {
    542             /* Found a child node - detach any attached object */
    543 
    544             AcpiNsDetachObject (ChildNode);
    545 
    546             /* Check if this node has any children */
    547 
    548             if (ChildNode->Child)
    549             {
    550                 /*
    551                  * There is at least one child of this node,
    552                  * visit the node
    553                  */
    554                 Level++;
    555                 ParentNode = ChildNode;
    556                 ChildNode  = NULL;
    557             }
    558         }
    559         else
    560         {
    561             /*
    562              * No more children of this parent node.
    563              * Move up to the grandparent.
    564              */
    565             Level--;
    566 
    567             /*
    568              * Now delete all of the children of this parent
    569              * all at the same time.
    570              */
    571             AcpiNsDeleteChildren (ParentNode);
    572 
    573             /* New "last child" is this parent node */
    574 
    575             ChildNode = ParentNode;
    576 
    577             /* Move up the tree to the grandparent */
    578 
    579             ParentNode = ParentNode->Parent;
    580         }
    581     }
    582 
    583     (void) AcpiUtReleaseMutex (ACPI_MTX_NAMESPACE);
    584     return_VOID;
    585 }
    586 
    587 
    588 /*******************************************************************************
    589  *
    590  * FUNCTION:    AcpiNsDeleteNamespaceByOwner
    591  *
    592  * PARAMETERS:  OwnerId     - All nodes with this owner will be deleted
    593  *
    594  * RETURN:      Status
    595  *
    596  * DESCRIPTION: Delete entries within the namespace that are owned by a
    597  *              specific ID. Used to delete entire ACPI tables. All
    598  *              reference counts are updated.
    599  *
    600  * MUTEX:       Locks namespace during deletion walk.
    601  *
    602  ******************************************************************************/
    603 
    604 void
    605 AcpiNsDeleteNamespaceByOwner (
    606     ACPI_OWNER_ID            OwnerId)
    607 {
    608     ACPI_NAMESPACE_NODE     *ChildNode;
    609     ACPI_NAMESPACE_NODE     *DeletionNode;
    610     ACPI_NAMESPACE_NODE     *ParentNode;
    611     UINT32                  Level;
    612     ACPI_STATUS             Status;
    613 
    614 
    615     ACPI_FUNCTION_TRACE_U32 (NsDeleteNamespaceByOwner, OwnerId);
    616 
    617 
    618     if (OwnerId == 0)
    619     {
    620         return_VOID;
    621     }
    622 
    623     /* Lock namespace for possible update */
    624 
    625     Status = AcpiUtAcquireMutex (ACPI_MTX_NAMESPACE);
    626     if (ACPI_FAILURE (Status))
    627     {
    628         return_VOID;
    629     }
    630 
    631     DeletionNode = NULL;
    632     ParentNode = AcpiGbl_RootNode;
    633     ChildNode = NULL;
    634     Level = 1;
    635 
    636     /*
    637      * Traverse the tree of nodes until we bubble back up
    638      * to where we started.
    639      */
    640     while (Level > 0)
    641     {
    642         /*
    643          * Get the next child of this parent node. When ChildNode is NULL,
    644          * the first child of the parent is returned
    645          */
    646         ChildNode = AcpiNsGetNextNode (ParentNode, ChildNode);
    647 
    648         if (DeletionNode)
    649         {
    650             AcpiNsDeleteChildren (DeletionNode);
    651             AcpiNsRemoveNode (DeletionNode);
    652             DeletionNode = NULL;
    653         }
    654 
    655         if (ChildNode)
    656         {
    657             if (ChildNode->OwnerId == OwnerId)
    658             {
    659                 /* Found a matching child node - detach any attached object */
    660 
    661                 AcpiNsDetachObject (ChildNode);
    662             }
    663 
    664             /* Check if this node has any children */
    665 
    666             if (ChildNode->Child)
    667             {
    668                 /*
    669                  * There is at least one child of this node,
    670                  * visit the node
    671                  */
    672                 Level++;
    673                 ParentNode = ChildNode;
    674                 ChildNode  = NULL;
    675             }
    676             else if (ChildNode->OwnerId == OwnerId)
    677             {
    678                 DeletionNode = ChildNode;
    679             }
    680         }
    681         else
    682         {
    683             /*
    684              * No more children of this parent node.
    685              * Move up to the grandparent.
    686              */
    687             Level--;
    688             if (Level != 0)
    689             {
    690                 if (ParentNode->OwnerId == OwnerId)
    691                 {
    692                     DeletionNode = ParentNode;
    693                 }
    694             }
    695 
    696             /* New "last child" is this parent node */
    697 
    698             ChildNode = ParentNode;
    699 
    700             /* Move up the tree to the grandparent */
    701 
    702             ParentNode = ParentNode->Parent;
    703         }
    704     }
    705 
    706     (void) AcpiUtReleaseMutex (ACPI_MTX_NAMESPACE);
    707     return_VOID;
    708 }
    709