ReturnIrp(
  IN  PIRP     pIrp,
  IN  int      status
  );

Routine Description:

    This function completes an IRP, and arranges for return parameters,
    if any, to be copied.

    Although somewhat a misnomer, this function is named after a similar
    function in the SpiderSTREAMS emulator.

Arguments:

    pIrp     -  pointer to the IRP to complete
    status  -  completion status of the IRP

Return Value:

    number of bytes copied back to the user.