reactos/ntoskrnl/io/mdl.c

   1 /* $Id: mdl.c,v 1.4 2000/03/05 19:17:43 ea Exp $
   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/mmhal.h>
  16
  17 #include <internal/debug.h>
  18
  19 /* FUNCTIONS *****************************************************************/
  20
  21 PMDL IoAllocateMdl(PVOID VirtualAddress,
  22                    ULONG Length,
  23                    BOOLEAN SecondaryBuffer,
  24                    BOOLEAN ChargeQuota,
  25                    PIRP Irp)
  26 {
  27    PMDL Mdl;
  28
  29    if (ChargeQuota)
  30      {
  31 //      Mdl = ExAllocatePoolWithQuota(NonPagedPool,
  32 //                                    MmSizeOfMdl(VirtualAddress,Length));
  33         Mdl = ExAllocatePool(NonPagedPool,MmSizeOfMdl(VirtualAddress,Length));
  34      }
  35    else
  36      {
  37         Mdl = ExAllocatePool(NonPagedPool,MmSizeOfMdl(VirtualAddress,Length));
  38      }
  39    MmInitializeMdl(Mdl,VirtualAddress,Length);
  40    if (Irp!=NULL && !SecondaryBuffer)
  41      {
  42         Irp->MdlAddress = Mdl;
  43      }
  44    return(Mdl);
  45 }
  46
  47 VOID IoBuildPartialMdl(PMDL SourceMdl,
  48                        PMDL TargetMdl,
  49                        PVOID VirtualAddress,
  50                        ULONG Length)
  51 {
  52    PULONG TargetPages = (PULONG)(TargetMdl + 1);
  53    PULONG SourcePages = (PULONG)(SourceMdl + 1);
  54    ULONG Va;
  55    ULONG Delta = (PAGE_ROUND_DOWN(VirtualAddress) - (ULONG)SourceMdl->StartVa)/
  56                  PAGESIZE;
  57
  58    for (Va = 0; Va < (PAGE_ROUND_UP(Length)/PAGESIZE); Va++)
  59      {
  60         TargetPages[Va] = SourcePages[Va+Delta];
  61      }
  62 }
  63
  64 VOID IoFreeMdl(PMDL Mdl)
  65 {
  66    MmUnmapLockedPages(MmGetSystemAddressForMdl(Mdl),Mdl);
  67    MmUnlockPages(Mdl);
  68    ExFreePool(Mdl);
  69 }
  70
  71
  72 /* EOF */