ntoskrnl/io/mdl.c

   1 /* $Id$
   2  *
   3  * COPYRIGHT:       See COPYING in the top level directory
   4  * PROJECT:         ReactOS kernel
   5  * FILE:            ntoskrnl/io/mdl.c
   6  * PURPOSE:         Io manager mdl functions
   7  * PROGRAMMER:      David Welch (welch@mcmail.com)
   8  * UPDATE HISTORY:
   9  *                  Created 22/05/98
  10  */
  11
  12 /* INCLUDES *****************************************************************/
  13
  14 #include <ddk/ntddk.h>
  15 #include <internal/pool.h>
  16
  17 #include <internal/debug.h>
  18
  19 /* GLOBALS *******************************************************************/
  20
  21 #define TAG_MDL    TAG('M', 'D', 'L', ' ')
  22
  23 /* FUNCTIONS *****************************************************************/
  24
  25 /*
  26  * @implemented
  27  */
  28 PMDL
  29 STDCALL
  30 IoAllocateMdl(PVOID VirtualAddress,
  31                    ULONG Length,
  32                    BOOLEAN SecondaryBuffer,
  33                    BOOLEAN ChargeQuota,
  34                    PIRP Irp)
  35 {
  36    PMDL Mdl;
  37
  38    if (ChargeQuota)
  39      {
  40 //      Mdl = ExAllocatePoolWithQuota(NonPagedPool,
  41 //                                    MmSizeOfMdl(VirtualAddress,Length));
  42         Mdl = ExAllocatePoolWithTag(NonPagedPool,
  43                                     MmSizeOfMdl(VirtualAddress,Length),
  44                                     TAG_MDL);
  45      }
  46    else
  47      {
  48         Mdl = ExAllocatePoolWithTag(NonPagedPool,
  49                                     MmSizeOfMdl(VirtualAddress,Length),
  50                                     TAG_MDL);
  51      }
  52    MmInitializeMdl(Mdl,VirtualAddress,Length);
  53    if (Irp!=NULL && !SecondaryBuffer)
  54      {
  55         Irp->MdlAddress = Mdl;
  56      }
  57    return(Mdl);
  58 }
  59
  60 /*
  61  * @implemented
  62  */
  63 VOID
  64 STDCALL
  65 IoBuildPartialMdl(PMDL SourceMdl,
  66                        PMDL TargetMdl,
  67                        PVOID VirtualAddress,
  68                        ULONG Length)
  69 {
  70    PULONG TargetPages = (PULONG)(TargetMdl + 1);
  71    PULONG SourcePages = (PULONG)(SourceMdl + 1);
  72    ULONG Va;
  73    ULONG Delta = (PAGE_ROUND_DOWN(VirtualAddress) - (ULONG)SourceMdl->StartVa)/
  74                  PAGE_SIZE;
  75
  76    for (Va = 0; Va < (PAGE_ROUND_UP(Length)/PAGE_SIZE); Va++)
  77      {
  78         TargetPages[Va] = SourcePages[Va+Delta];
  79      }
  80 }
  81
  82 /*
  83  * @implemented
  84  */
  85 VOID STDCALL
  86 IoFreeMdl(PMDL Mdl)
  87 {
  88    MmUnmapLockedPages(MmGetSystemAddressForMdl(Mdl), Mdl);
  89    MmUnlockPages(Mdl);
  90    ExFreePool(Mdl);
  91 }
  92
  93
  94 /* EOF */