WDF驱动如何向底层磁盘驱动发送IRP_MJ_READ请求读取原始数据？请给出示例

WDF驱动向底层磁盘驱动发送IRP_MJ_READ请求读取原始数据的示例代码如下：

NTSTATUS ReadFromDisk(WDFDEVICE Device, PVOID Buffer, ULONG Length)
{
    NTSTATUS status = STATUS_SUCCESS;
    WDFREQUEST request = NULL;
    PIRP irp = NULL;
    KEVENT event;
    IO_STATUS_BLOCK ioStatusBlock;

    // 初始化事件
    KeInitializeEvent(&event, NotificationEvent, FALSE);

    // 创建请求对象
    status = WdfRequestCreate(WDF_NO_OBJECT_ATTRIBUTES, WdfDeviceGetIoTarget(Device), &request);
    if (!NT_SUCCESS(status)) {
        return status;
    }

    // 获取IRP对象
    irp = WdfRequestWdmGetIrp(request);

    // 设置IRP参数
    IoSetCompletionRoutine(irp, ReadCompletionRoutine, &event, TRUE, TRUE, TRUE);
    irp->Flags |= IRP_BUFFERED_IO | IRP_DEALLOCATE_BUFFER;
    irp->AssociatedIrp.SystemBuffer = Buffer;
    irp->MdlAddress = NULL;
    irp->IoStatus.Status = STATUS_NOT_SUPPORTED;
    irp->IoStatus.Information = 0;
    irp->Tail.Overlay.Thread = PsGetCurrentThread();
    irp->Tail.Overlay.OriginalFileObject = NULL;
    irp->Tail.Overlay.AuxiliaryBuffer = NULL;
    irp->Flags &= ~(IRP_PAGING_IO | IRP_NOCACHE | IRP_SYNCHRONOUS_API);

    // 设置IO栈位置
    PIO_STACK_LOCATION irpStack = IoGetNextIrpStackLocation(irp);
    irpStack->MajorFunction = IRP_MJ_READ;
    irpStack->Parameters.Read.Length = Length;
    irpStack->Parameters.Read.ByteOffset.QuadPart = 0;

    // 发送IRP请求
    status = WdfRequestSend(request, WdfDeviceGetIoTarget(Device), WDF_NO_SEND_OPTIONS);
    if (!NT_SUCCESS(status)) {
        WdfRequestComplete(request, status);
        return status;
    }

    // 等待请求完成
    KeWaitForSingleObject(&event, Executive, KernelMode, FALSE, NULL);

    // 获取IO状态
    status = irp->IoStatus.Status;

    // 完成请求
    WdfRequestComplete(request, status);

    return status;
}

在以上代码中，我们创建了一个WDF请求对象，并获取了其对应的IRP对象，然后设置了IRP的各项参数，最终发送请求并等待请求完成。一旦请求完成，我们就可以通过IRP的IoStatus成员获取IO操作的状态，然后使用WdfRequestComplete函数完成请求。