VOID
NdisProtCancelWrite(
IN PDEVICE_OBJECT pDeviceObject,
IN PIRP pIrp
)
/*++
Routine Description:
Cancel a pending write IRP. This routine attempt to cancel the NDIS send.
Arguments:
pDeviceObject - pointer to our device object
pIrp - IRP to be cancelled
Return Value:
None
--*/
{
PNDISPROT_OPEN_CONTEXT pOpenContext;
PLIST_ENTRY pIrpEntry;
PNDIS_PACKET pNdisPacket;
UNREFERENCED_PARAMETER(pDeviceObject);
IoReleaseCancelSpinLock(pIrp->CancelIrql);
//
// The NDIS packet representing this Write IRP.
//
pNdisPacket = NULL;
pOpenContext = (PNDISPROT_OPEN_CONTEXT) pIrp->Tail.Overlay.DriverContext[0];
NPROT_STRUCT_ASSERT(pOpenContext, oc);
//
// Try to locate the IRP in the pended write queue. The send completion
// routine may be running and might have removed it from there.
//
NPROT_ACQUIRE_LOCK(&pOpenContext->Lock);
for (pIrpEntry = pOpenContext->PendedWrites.Flink;
pIrpEntry != &pOpenContext->PendedWrites;
pIrpEntry = pIrpEntry->Flink)
{
if (pIrp == CONTAINING_RECORD(pIrpEntry, IRP, Tail.Overlay.ListEntry))
{
pNdisPacket = (PNDIS_PACKET) pIrp->Tail.Overlay.DriverContext[1];
//
// Place a reference on this packet so that it won't get
// freed/reused until we are done with it.
//
NPROT_REF_SEND_PKT(pNdisPacket);
break;
}
}
NPROT_RELEASE_LOCK(&pOpenContext->Lock);
if (pNdisPacket != NULL)
{
//
// Either the send completion routine hasn't run, or we got a peak
// at the IRP/packet before it had a chance to take it out of the
// pending IRP queue.
//
// We do not complete the IRP here - note that we didn't dequeue it
// above. This is because we always want the send complete routine to
// complete the IRP. And this in turn is because the packet that was
// prepared from the IRP has a buffer chain pointing to data associated
// with this IRP. Therefore we cannot complete the IRP before the driver
// below us is done with the data it pointed to.
//
//
// Request NDIS to cancel this send. The result of this call is that
// our SendComplete handler will be called (if not already called).
//
DEBUGP(DL_INFO, ("CancelWrite: cancelling pkt %p on Open %p\n",
pNdisPacket, pOpenContext));
NdisCancelSendPackets(
pOpenContext->BindingHandle,
NDIS_GET_PACKET_CANCEL_ID(pNdisPacket)
);
//
// It is now safe to remove the reference we had placed on the packet.
//
NPROT_DEREF_SEND_PKT(pNdisPacket);
}
//
// else the send completion routine has already picked up this IRP.
//
}
VOID
SecLabCancelWrite(
IN PDEVICE_OBJECT pDeviceObject,
IN PIRP pIrp
)
/*++
Routine Description:
Cancel a pending write IRP. This routine attempt to cancel the NDIS send.
Arguments:
pDeviceObject - pointer to our device object
pIrp - IRP to be cancelled
Return Value:
None
--*/
{
PADAPT pAdapt;
PLIST_ENTRY pIrpEntry;
PNDIS_PACKET pNdisPacket;
IoReleaseCancelSpinLock(pIrp->CancelIrql);
//
// 一个封包代表一个写IRP.
//
pNdisPacket = NULL;
pAdapt = (PADAPT) pIrp->Tail.Overlay.DriverContext[0];
if(pAdapt==NULL)
{
DbgPrint("The Adapt handle is NULL");
DbgBreakPoint();
}
DbgPrint("once enter the cancel routain");
//
// 在写IRP阻塞队列中定位要取消的IRP. 发送完成例程可能已经运行并将其释放
//
NdisAcquireSpinLock(&WriteIrpLock);
for (pIrpEntry = PendedWritesList.Flink;
pIrpEntry != &PendedWritesList;
pIrpEntry = pIrpEntry->Flink)
{
if (pIrp == CONTAINING_RECORD(pIrpEntry, IRP, Tail.Overlay.ListEntry))
{
pNdisPacket = (PNDIS_PACKET) pIrp->Tail.Overlay.DriverContext[1];
//
// 将此等待IRP代表的封包结构中的RefCount置1.这样在它
// 完成之前就不会被释放或重用了
//
SECLAB_REF_SEND_PKT(pNdisPacket);
break;
}
}
NdisReleaseSpinLock(&WriteIrpLock);
if (pNdisPacket != NULL)
{
//
// Either the send completion routine hasn't run, or we got a peak
// at the IRP/packet before it had a chance to take it out of the
// pending IRP queue.
//
// We do not complete the IRP here - note that we didn't dequeue it
// above. This is because we always want the send complete routine to
// complete the IRP. And this in turn is because the packet that was
// prepared from the IRP has a buffer chain pointing to data associated
// with this IRP. Therefore we cannot complete the IRP before the driver
// below us is done with the data it pointed to.
//
//
// Request NDIS to cancel this send. The result of this call is that
// our SendComplete handler will be called (if not already called).
//
NdisCancelSendPackets(
pAdapt->BindingHandle,
NDIS_GET_PACKET_CANCEL_ID(pNdisPacket)
);
//
// It is now safe to remove the reference we had placed on the packet.
//
SECLAB_DEREF_SEND_PKT(pNdisPacket);
}
//
// else the send completion routine has already picked up this IRP.
//
}
