reactos/ntoskrnl/io/mdl.c

   1 /* $Id: mdl.c,v 1.16 2004/08/01 07:24:57 hbirr 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/pool.h>
  16 #include <internal/mm.h>
  17
  18 #define NDEBUG
  19 #include <internal/debug.h>
  20
  21 /* GLOBALS *******************************************************************/
  22
  23 #define TAG_MDL    TAG('M', 'D', 'L', ' ')
  24
  25 /* FUNCTIONS *****************************************************************/
  26
  27 /*
  28  * @implemented
  29  */
  30 PMDL
  31 STDCALL
  32 IoAllocateMdl(PVOID VirtualAddress,
  33                    ULONG Length,
  34                    BOOLEAN SecondaryBuffer,
  35                    BOOLEAN ChargeQuota,
  36                    PIRP Irp)
  37 {
  38    PMDL Mdl;
  39
  40    if (ChargeQuota)
  41      {
  42 //      Mdl = ExAllocatePoolWithQuota(NonPagedPool,
  43 //                                    MmSizeOfMdl(VirtualAddress,Length));
  44         Mdl = ExAllocatePoolWithTag(NonPagedPool,
  45                                     MmSizeOfMdl(VirtualAddress,Length),
  46                                     TAG_MDL);
  47      }
  48    else
  49      {
  50         Mdl = ExAllocatePoolWithTag(NonPagedPool,
  51                                     MmSizeOfMdl(VirtualAddress,Length),
  52                                     TAG_MDL);
  53      }
  54    MmInitializeMdl(Mdl, (char*)VirtualAddress, Length);
  55
  56    if (Irp)
  57    {
  58       if (SecondaryBuffer)
  59       {
  60          assert(Irp->MdlAddress);
  61
  62          /* FIXME: add to end of list maybe?? */
  63          Mdl->Next = Irp->MdlAddress->Next;
  64          Irp->MdlAddress->Next = Mdl;
  65       }
  66       else
  67       {
  68          /*
  69           * What if there's allready an mdl at Irp->MdlAddress?
  70           * Is that bad and should we do something about it?
  71           */
  72          Irp->MdlAddress = Mdl;
  73       }
  74    }
  75
  76    return(Mdl);
  77 }
  78
  79 /*
  80  * @implemented
  81  *
  82  * You must IoFreeMdl the slave before freeing the master.
  83  *
  84  * IoBuildPartialMdl is more similar to MmBuildMdlForNonPagedPool, the difference
  85  * is that the former takes the physical addresses from the master MDL, while the
  86  * latter - from the known location of the NPP.
  87  */
  88 VOID
  89 STDCALL
  90 IoBuildPartialMdl(PMDL SourceMdl,
  91                        PMDL TargetMdl,
  92                        PVOID VirtualAddress,
  93                        ULONG Length)
  94 {
  95    PPFN_TYPE TargetPages = (PPFN_TYPE)(TargetMdl + 1);
  96    PPFN_TYPE SourcePages = (PPFN_TYPE)(SourceMdl + 1);
  97    ULONG Count;
  98    ULONG Delta;
  99
 100    DPRINT("VirtualAddress %x, SourceMdl->StartVa %x, SourceMdl->MappedSystemVa %x\n",
 101           VirtualAddress, SourceMdl->StartVa, SourceMdl->MappedSystemVa);
 102
 103    TargetMdl->StartVa = (PVOID)PAGE_ROUND_DOWN(VirtualAddress);
 104    TargetMdl->ByteOffset = (ULONG_PTR)VirtualAddress - (ULONG_PTR)TargetMdl->StartVa;
 105    TargetMdl->ByteCount = Length;
 106    TargetMdl->Process = SourceMdl->Process;
 107    Delta = (ULONG_PTR)VirtualAddress - ((ULONG_PTR)SourceMdl->StartVa + SourceMdl->ByteOffset);
 108    TargetMdl->MappedSystemVa = SourceMdl->MappedSystemVa + Delta;
 109
 110    TargetMdl->MdlFlags = SourceMdl->MdlFlags & (MDL_IO_PAGE_READ|MDL_SOURCE_IS_NONPAGED_POOL|MDL_MAPPED_TO_SYSTEM_VA);
 111    TargetMdl->MdlFlags |= MDL_PARTIAL;
 112
 113    Delta = ((ULONG_PTR)TargetMdl->StartVa - (ULONG_PTR)SourceMdl->StartVa) / PAGE_SIZE;
 114    Count = ADDRESS_AND_SIZE_TO_SPAN_PAGES(VirtualAddress,Length);
 115
 116    SourcePages += Delta;
 117
 118    DPRINT("Delta %d, Count %d\n", Delta, Count);
 119
 120    memcpy(TargetPages, SourcePages, Count * sizeof(PFN_TYPE));
 121
 122 }
 123
 124 /*
 125  * @implemented
 126  */
 127 VOID STDCALL
 128 IoFreeMdl(PMDL Mdl)
 129 {
 130    /*
 131     * This unmaps partial mdl's from kernel space but also asserts that non-partial
 132     * mdl's isn't still mapped into kernel space.
 133     */
 134    MmPrepareMdlForReuse(Mdl);
 135
 136    ExFreePool(Mdl);
 137 }
 138
 139
 140 /* EOF */