WdfRequestForwardToIoQueue method

[Applies to KMDF and UMDF]

The WdfRequestForwardToIoQueue method requeues an I/O request to one of the calling driver's I/O queues.

Syntax


NTSTATUS WdfRequestForwardToIoQueue(
  [in] WDFREQUEST Request,
  [in] WDFQUEUE   DestinationQueue
);

Parameters

Request [in]

A handle to a framework request object.

DestinationQueue [in]

A handle to a framework queue object.

Return value

WdfRequestForwardToIoQueue returns STATUS_SUCCESS if the operation succeeds. Otherwise, this method might return one of the following values:

Return codeDescription
STATUS_INVALID_DEVICE_REQUEST

This value is returned if one of the following occurs:

  • The driver did not obtain the request from an I/O queue.

  • The source and destination queues are the same.

  • The source and destination queues do not belong to the same device.

  • The driver does not own the request.

  • The request is cancelable.

STATUS_WDF_BUSY

The destination queue is not accepting new requests.

 

This method might also return other NTSTATUS values.

A bug check occurs if the driver supplies an invalid object handle.

Remarks

The driver must own the I/O request and must have obtained the request from one of its I/O queues.

The source and destination queues cannot be the same. In other words, the driver cannot call WdfRequestForwardToIoQueue to return a request to the queue that it came from. To requeue a request to the same queue, use WdfRequestRequeue.

Both the source and destination queues must belong to the same device.

The request must not be cancelable. If the driver has called WdfRequestMarkCancelable or WdfRequestMarkCancelableEx to make the request cancelable, it must call WdfRequestUnmarkCancelable before calling WdfRequestForwardToIoQueue.

After the driver calls WdfRequestForwardToIoQueue, the driver does not own the requeued request until the framework delivers the request from the new queue to the driver. While the request is in the new queue, the framework owns the request and can cancel it without notifying the driver.

Before WdfRequestForwardToIoQueue returns, the following events can occur:

  • If the destination queue was empty, the framework can deliver the requeued I/O request to one of the destination queue's request handlers.

  • If the source queue's dispatching method is sequential or parallel, the framework can deliver another request to one of the source queue's request handlers.

For more information about WdfRequestForwardToIoQueue, see Requeuing I/O Requests and Managing I/O Queues.

Examples

The following code example is an EvtIoDeviceControl callback function from the PCIDRV sample driver. If a received request contains an I/O control code of IOCTL_NDISPROT_INDICATE_STATUS, the driver calls WdfRequestForwardToIoQueue to move the request to a different I/O queue.


VOID
PciDrvEvtIoDeviceControl(
    IN WDFQUEUE  Queue,
    IN WDFREQUEST  Request,
    IN size_t  OutputBufferLength,
    IN size_t  InputBufferLength,
    IN ULONG  IoControlCode
    )
{
    NTSTATUS  status= STATUS_SUCCESS;
    PFDO_DATA  fdoData = NULL;
    WDFDEVICE  hDevice;
    WDF_REQUEST_PARAMETERS  params;

    UNREFERENCED_PARAMETER(OutputBufferLength);
    UNREFERENCED_PARAMETER(InputBufferLength);

    hDevice = WdfIoQueueGetDevice(Queue);
    fdoData = FdoGetData(hDevice);

    WDF_REQUEST_PARAMETERS_INIT(&params);
    WdfRequestGetParameters(
                            Request,
                            &params
                            );

    switch (IoControlCode)
    {
        case IOCTL_NDISPROT_QUERY_OID_VALUE:
            NICHandleQueryOidRequest(
                                     Queue,
                                     Request,
                                     &params
                                     );
            break;

        case IOCTL_NDISPROT_SET_OID_VALUE:
            NICHandleSetOidRequest(
                                   Queue,
                                   Request,
                                   &params
                                   );
            break;

        case IOCTL_NDISPROT_INDICATE_STATUS:
            status = WdfRequestForwardToIoQueue(
                                                Request,
                                                fdoData->PendingIoctlQueue
                                                );
            if(!NT_SUCCESS(status)){
                WdfRequestComplete(
                                   Request,
                                   status
                                   );
                break;
            }
            break;

        default:
            WdfRequestComplete(
                               Request,
                               STATUS_INVALID_DEVICE_REQUEST
                               );
            break;
    }
    return;
}

Requirements

Target platform

Universal

Minimum KMDF version

1.0

Minimum UMDF version

2.0

Header

Wdfrequest.h (include Wdf.h)

Library

Wdf01000.sys (KMDF);
WUDFx02000.dll (UMDF)

IRQL

<=DISPATCH_LEVEL

DDI compliance rules

DeferredRequestCompleted, DriverCreate, InvalidReqAccess, InvalidReqAccessLocal, KmdfIrql, KmdfIrql2, RequestCompleted, RequestCompletedLocal

See also

WdfRequestMarkCancelable
WdfRequestMarkCancelableEx
WdfRequestUnmarkCancelable
WdfRequestRequeue
EvtDestroyCallback

 

 

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