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 PMDL
  26 STDCALL
  27 IoAllocateMdl(PVOID VirtualAddress,
  28                    ULONG Length,
  29                    BOOLEAN SecondaryBuffer,
  30                    BOOLEAN ChargeQuota,
  31                    PIRP Irp)
  32 {
  33    PMDL Mdl;
  34
  35    if (ChargeQuota)
  36      {
  37 //      Mdl = ExAllocatePoolWithQuota(NonPagedPool,
  38 //                                    MmSizeOfMdl(VirtualAddress,Length));
  39         Mdl = ExAllocatePoolWithTag(NonPagedPool,
  40                                     MmSizeOfMdl(VirtualAddress,Length),
  41                                     TAG_MDL);
  42      }
  43    else
  44      {
  45         Mdl = ExAllocatePoolWithTag(NonPagedPool,
  46                                     MmSizeOfMdl(VirtualAddress,Length),
  47                                     TAG_MDL);
  48      }
  49    MmInitializeMdl(Mdl,VirtualAddress,Length);
  50    if (Irp!=NULL && !SecondaryBuffer)
  51      {
  52         Irp->MdlAddress = Mdl;
  53      }
  54    return(Mdl);
  55 }
  56
  57 VOID
  58 STDCALL
  59 IoBuildPartialMdl(PMDL SourceMdl,
  60                        PMDL TargetMdl,
  61                        PVOID VirtualAddress,
  62                        ULONG Length)
  63 {
  64    PULONG TargetPages = (PULONG)(TargetMdl + 1);
  65    PULONG SourcePages = (PULONG)(SourceMdl + 1);
  66    ULONG Va;
  67    ULONG Delta = (PAGE_ROUND_DOWN(VirtualAddress) - (ULONG)SourceMdl->StartVa)/
  68                  PAGE_SIZE;
  69
  70    for (Va = 0; Va < (PAGE_ROUND_UP(Length)/PAGE_SIZE); Va++)
  71      {
  72         TargetPages[Va] = SourcePages[Va+Delta];
  73      }
  74 }
  75
  76 VOID STDCALL
  77 IoFreeMdl(PMDL Mdl)
  78 {
  79    MmUnmapLockedPages(MmGetSystemAddressForMdl(Mdl), Mdl);
  80    MmUnlockPages(Mdl);
  81    ExFreePool(Mdl);
  82 }
  83
  84
  85 /* EOF */