IRP.Tail.ListEntry

IRP.Tail.ListEntry 用于用户自定义LIST_ENTRY使用。
如我们对IRP进行链表管理：

VOID RecycleIrp(IN PFDO_DEVICE_EXTENSION DeviceExtension, PIRP Irp)
{
    KIRQL OldLevel;
    KeAcquireSpinLock(&DeviceExtension->IrpRecyledListLock, &OldLevel);
    InsertTailList(&DeviceExtension->IrpRecyledListHead, &Irp->Tail.Overlay.ListEntry);
    KeReleaseSpinLock(&DeviceExtension->IrpRecyledListLock, OldLevel);
}

VOID ResetIrp(IN PFDO_DEVICE_EXTENSION DeviceExtension)
{
    KIRQL OldLevel;
    KeAcquireSpinLock(&DeviceExtension->IrpRecyledListLock, &OldLevel);
    while (!IsListEmpty(&DeviceExtension->IrpRecyledListHead))
    {
        PLIST_ENTRY entry = RemoveHeadList(&DeviceExtension->IrpRecyledListHead);
        IRP* irp = CONTAINING_RECORD(entry, IRP, Tail.Overlay.ListEntry);
        IoFreeIrp(irp);
    }
    KeReleaseSpinLock(&DeviceExtension->IrpRecyledListLock, OldLevel);
}


PIRP
GetIrp(
    IN PFDO_DEVICE_EXTENSION DeviceExtension)
{
    KIRQL OldLevel;
    PIRP Irp = NULL;
    PLIST_ENTRY ListEntry;

    KeAcquireSpinLock(&DeviceExtension->IrpRecyledListLock, &OldLevel);
    if (!IsListEmpty(&DeviceExtension->IrpRecyledListHead))
    {
        ListEntry = RemoveHeadList(&DeviceExtension->IrpRecyledListHead);
        Irp = CONTAINING_RECORD(ListEntry, IRP, Tail.Overlay.ListEntry);
    }

    KeReleaseSpinLock(&DeviceExtension->IrpRecyledListLock, OldLevel);
    return Irp;
}

PIRP
BuildIrp(
    IN PFDO_DEVICE_EXTENSION DeviceExtension)
{
    PIRP Irp;
    Irp = GetIrp(DeviceExtension);
    if (!Irp)
    {
        Irp = IoAllocateIrp(DeviceExtension->NextDeviceObject->StackSize + 1, FALSE);
        if (!Irp)
        {
            return NULL;
        }
    }
    else
    {
        IoReuseIrp(Irp, STATUS_SUCCESS);
    }

    return  Irp;
}

IRP关于 IRP.Tail.ListEntry的结构体如下：

             struct {

                //
                // List entry - used to queue the packet to completion queue, among
                // others.
                //

                LIST_ENTRY ListEntry;

                union {

                    //
                    // Current stack location - contains a pointer to the current
                    // IO_STACK_LOCATION structure in the IRP stack.  This field
                    // should never be directly accessed by drivers.  They should
                    // use the standard functions.
                    //

                    struct _IO_STACK_LOCATION *CurrentStackLocation;

                    //
                    // Minipacket type.
                    //

                    ULONG PacketType;
                };
            };

            //
            // Original file object - pointer to the original file object
            // that was used to open the file.  This field is owned by the
            // I/O system and should not be used by any other drivers.
            //

            PFILE_OBJECT OriginalFileObject;

        } Overlay;

可参考代码如下：