_Must_inspect_result_
PVOID
FxRequestSystemBuffer::GetBuffer(
VOID
)
/*++
Routine Description:
Returns the system buffer that has been cached away by the call to SetBuffer()
Arguments:
None
Return Value:
Valid memory or NULL on error
--*/
{
FxDevice* pDevice;
FxIrp* irp = GetRequest()->GetFxIrp();
WDF_DEVICE_IO_TYPE ioType;
switch (irp->GetMajorFunction()) {
case IRP_MJ_DEVICE_CONTROL:
case IRP_MJ_INTERNAL_DEVICE_CONTROL:
return m_Buffer;
case IRP_MJ_READ:
case IRP_MJ_WRITE:
pDevice = FxDevice::GetFxDevice(irp->GetDeviceObject());
ioType = pDevice->GetIoType();
switch (ioType) {
case WdfDeviceIoBuffered:
return m_Buffer;
case WdfDeviceIoDirect:
//
// FxRequest::GetMemoryObject has already called MmGetSystemAddressForMdlSafe
// and returned success, so we know that we can safely call
// MmGetSystemAddressForMdlSafe again to get a valid VA pointer.
//
return Mx::MxGetSystemAddressForMdlSafe(m_Mdl, NormalPagePriority);
case WdfDeviceIoNeither:
return m_Buffer;
default:
ASSERT(FALSE);
return NULL;
}
default:
ASSERT(FALSE);
return NULL;
}
}
//
// This inserts a request into the I/O processing pipeline
//
_Must_inspect_result_
NTSTATUS
FxPkgIo::EnqueueRequest(
__in CfxDevice* Device,
__inout FxRequest* pRequest
)
{
NTSTATUS status;
FxIoQueue* pQueue;
FxIrp* Irp = NULL;
FxRequestCompletionState oldState;
PFX_DRIVER_GLOBALS FxDriverGlobals = GetDriverGlobals();
SHORT origVerifierFlags = 0;
//
// Request is owned by the driver, and has a reference count of == 1
// (or > 1 if EvtIoInCallerContext callback took an additional reference),
// with a FxPkgIoInProcessRequestComplete callback registered.
//
ASSERT(pRequest->GetRefCnt() >= 1);
Irp = pRequest->GetFxIrp();
DoTraceLevelMessage(FxDriverGlobals, TRACE_LEVEL_VERBOSE, TRACINGIO,
"WDFREQUEST 0x%p", pRequest->GetObjectHandle());
status = VerifyEnqueueRequestUpdateFlags(FxDriverGlobals,
pRequest,
&origVerifierFlags);
if (!NT_SUCCESS(status)) {
return status;
}
//
// Get the associated queue
//
pQueue = (FxIoQueue*) pRequest->GetInternalContext();
if (NULL == pQueue) {
pQueue = m_DispatchTable[Irp->GetMajorFunction()];
if (pQueue == NULL) {
//
// No queue configured yet, fail request unless the driver is a filter.
//
if (m_Filter) {
goto Forward;
}
status = STATUS_INVALID_DEVICE_REQUEST;
DoTraceLevelMessage(FxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGIO,
"No queue configured for WDFDEVICE 0x%p, "
"failing WDFREQUEST 0x%p %!STATUS!",
Device->GetHandle(),
pRequest->GetObjectHandle(),
status);
FxVerifierDbgBreakPoint(FxDriverGlobals);
//
// Return it back to the driver to decide the outcome
//
goto Error;
}
}
//
// If the queue is a default-queue and driver is a filter then before
// calling the queue we should make sure the queue can dispatch
// requests to the driver. If the queue cannot dispatch request,
// we should forward it down to the lower driver ourself.
if (m_Filter &&
pQueue == m_DefaultQueue &&
pQueue->IsIoEventHandlerRegistered((WDF_REQUEST_TYPE)Irp->GetMajorFunction()) == FALSE) {
//
// Default queue doesn't have callback events registered to
// handle this request. So forward it down.
//
goto Forward;
}
pQueue->AddRef();
// Must add a reference before releasing the callback and its reference
pRequest->ADDREF(FXREQUEST_STATE_TAG);
// Release the callback
oldState = pRequest->SetCompletionState(FxRequestCompletionStateNone);
ASSERT(oldState != FxRequestCompletionStateNone);
UNREFERENCED_PARAMETER(oldState);
status = pQueue->QueueRequestFromForward(pRequest);
pQueue->Release();
//
// If not successfull, must place the request back
// to the state it was in on entry so that the driver
// can decide what to do next with it
//
if (!NT_SUCCESS(status)) {
//
// If the request comes back to us, it should still
// have a reference count of 1
//
oldState = pRequest->SetCompletionState(FxRequestCompletionStateIoPkg);
ASSERT(oldState == FxRequestCompletionStateNone);
UNREFERENCED_PARAMETER(oldState);
//
// Release the reference count on the request since
// the callback will hold the only one that gets
// decremented when the request is completed
//
pRequest->RELEASE(FXREQUEST_STATE_TAG);
goto Error;
}
else {
//
// On success, can not touch the request since it
// may have already been completed
//
}
return status;
Forward:
//
// Cannot send-and-forget a request with a formatted IO context.
//
if (pRequest->HasContext()) {
status = STATUS_INVALID_DEVICE_REQUEST;
DoTraceLevelMessage(
FxDriverGlobals, TRACE_LEVEL_ERROR, TRACINGIO,
"Cannot send-and-forget WDFREQUEST 0x%p with formatted IO"
" context for filter WDFDEVICE 0x%p, %!STATUS!",
pRequest->GetObjectHandle(),
Device->GetHandle(),
status );
FxVerifierDbgBreakPoint(FxDriverGlobals);
goto Error;
}
//
// This will skip the current stack location and perform
// early dispose on the request.
//
pRequest->PreProcessSendAndForget();
(VOID)Irp->CallDriver(Device->GetAttachedDevice());
//
// This will delete the request and free the memory back
// to the device lookaside list.
//
pRequest->PostProcessSendAndForget();
//
// Return a success status in this code path even if the previous call
// to send the request to the lower driver failed. The status code returned
// by this function should reflect the status of enqueuing the request and
// not the status returned by the lower driver.
//
return STATUS_SUCCESS;
Error:
//
// If not successful, we must set the original verifier flags.
//
VerifyEnqueueRequestRestoreFlags(FxDriverGlobals, pRequest, origVerifierFlags);
return status;
}
