NTSTATUS
NTGetIrpIfNotCancelled(
  IN  PIRP            pIrp,
  IN  PIRP            *ppIrpInStruct
  );
Routine Description:

    This Routine gets the IOCancelSpinLock to coordinate with cancelling
    irps It then returns STATUS_SUCCESS. It also nulls the irp in the structure
    pointed to by the second parameter - so that the irp cancel routine
    will not also be called.

Arguments:

    status - a completion status for the Irp

Return Value:

    NTSTATUS - status of the request