HidClassFDO_DispatchRequest

NTSTATUS
HidClassFDO_DispatchRequest(
    IN PDEVICE_OBJECT DeviceObject,
    IN PIRP Irp)
{
    PHIDCLASS_COMMON_DEVICE_EXTENSION CommonDeviceExtension;
    NTSTATUS Status;
    PIO_STACK_LOCATION IoStack;

    //
    // get device extension
    //
    CommonDeviceExtension = DeviceObject->DeviceExtension;

    ASSERT(Irp->CurrentLocation > 0);

    //
    // create stack location
    //
    IoSetNextIrpStackLocation(Irp);

    //
    // get next stack location
    //
    IoStack = IoGetCurrentIrpStackLocation(Irp);

    //
    // store device object
    //
    IoStack->DeviceObject = DeviceObject;

    //
    // sanity check
    //
    ASSERT(CommonDeviceExtension->DriverExtension->MajorFunction[IoStack->MajorFunction] != NULL);

    //
    // call driver
    //
    Status = CommonDeviceExtension->DriverExtension->MajorFunction[IoStack->MajorFunction](DeviceObject, Irp);

    //
    // done
    //
    return Status;
}

IoSetNextIrpStackLocationion源代码

FORCEINLINE
VOID
IoSetNextIrpStackLocation (
   _Inout_ PIRP Irp
    )
/*--

Routine Description:

    This routine is invoked to set the current IRP stack location to
    the next stack location, i.e. it "pushes" the stack.

Arguments:

    Irp - Pointer to the I/O Request Packet (IRP).

Return Value:

    None.

--*/
{
    NT_ASSERT(Irp->CurrentLocation > 0);
    Irp->CurrentLocation--;
    Irp->Tail.Overlay.CurrentStackLocation--;
}