/*
* @implemented
*/
PMDL
NTAPI
MmCreateMdl(IN PMDL Mdl,
IN PVOID Base,
IN SIZE_T Length)
{
SIZE_T Size;
//
// Check if we don't have an MDL built
//
if (!Mdl)
{
//
// Calculate the size we'll need and allocate the MDL
//
Size = MmSizeOfMdl(Base, Length);
Mdl = ExAllocatePoolWithTag(NonPagedPool, Size, TAG_MDL);
if (!Mdl) return NULL;
}
//
// Initialize it
//
MmInitializeMdl(Mdl, Base, Length);
return Mdl;
}
FORCEINLINE
NTSTATUS
FxRequestBuffer::GetOrAllocateMdlWorker(
__in PFX_DRIVER_GLOBALS FxDriverGlobals,
__deref_out PMDL* Mdl,
__in BOOLEAN * ReuseMdl,
__in LONG Length,
__in PVOID Buffer,
__inout size_t* SizeOfMdl,
__in BOOLEAN UnlockWhenFreed,
__deref_out_opt PMDL* MdlToFree
)
{
size_t sizeofCurrentMdl;
sizeofCurrentMdl = MmSizeOfMdl(Buffer, Length);
//
// Caller of this function (GetOrAllocateMdl) verifies that pages
// are already unlocked. Asserting here, in case we start using this
// function elsewhere.
//
// This is why we don't unlock pages either in reuse or non-reuse case.
//
ASSERT(UnlockWhenFreed == FALSE);
UNREFERENCED_PARAMETER(UnlockWhenFreed); //for fre build
//
// If ReuseMdl is TRUE then the Mdl to be reused is passed in.
//
if (*ReuseMdl && sizeofCurrentMdl <= *SizeOfMdl) {
MmPrepareMdlForReuse(*MdlToFree);
*Mdl = *MdlToFree;
}
else {
*ReuseMdl = FALSE;
//
// Since *Mdl may have the original IRP Mdl
// free *MdlToFree and not *Mdl
//
if (*MdlToFree != NULL) {
FxMdlFree(FxDriverGlobals, *MdlToFree);
*MdlToFree = NULL;
if (SizeOfMdl != NULL) {
*SizeOfMdl = 0;
}
}
*Mdl = FxMdlAllocate(FxDriverGlobals,
NULL, // owning FxObject
Buffer,
Length,
FALSE,
FALSE);
if (*Mdl == NULL) {
ASSERT(SizeOfMdl ? (*SizeOfMdl == 0) : TRUE);
return STATUS_INSUFFICIENT_RESOURCES;
}
if (SizeOfMdl != NULL) {
*SizeOfMdl = sizeofCurrentMdl;
}
}
return STATUS_SUCCESS;
}
