WDF_IO_QUEUE_FORWARD_PROGRESS_POLICY_PAGINGIO_INIT function (wdfio.h)

Article
10/21/2021

[Applies to KMDF only]

The WDF_IO_QUEUE_FORWARD_PROGRESS_POLICY_PAGINGIO_INIT function initializes a driver's WDF_IO_QUEUE_FORWARD_PROGRESS_POLICY structure.

Syntax

void WDF_IO_QUEUE_FORWARD_PROGRESS_POLICY_PAGINGIO_INIT(
  [out] PWDF_IO_QUEUE_FORWARD_PROGRESS_POLICY Policy,
  [in]  ULONG                                 TotalForwardProgressRequests
);

Parameters

[out] Policy

A pointer to the driver's WDF_IO_QUEUE_FORWARD_PROGRESS_POLICY structure.

[in] TotalForwardProgressRequests

The number of request objects that the framework will attempt to reserve for use in low-memory situations. This number must be greater than zero.

Return value

None

Remarks

The WDF_IO_QUEUE_FORWARD_PROGRESS_POLICY_PAGINGIO_INIT function zeros the specified WDF_IO_QUEUE_FORWARD_PROGRESS_POLICY structure and sets its Size member. It also sets the ForwardProgressReservedPolicy member to WdfIoForwardProgressReservedPolicyUseExamine.

Examples

The following code example initializes a WDF_IO_QUEUE_FORWARD_PROGRESS_POLICY structure and then calls WdfIoQueueAssignForwardProgressPolicy. In the example, the driver is specifying that the framework should allocate and reserve 10 request objects for low-memory situations, and that the framework should use one of the reserved requests during low-memory situations only if the I/O request is a paging operation.

#define MAX_RESERVED_REQUESTS 10

WDF_IO_QUEUE_FORWARD_PROGRESS_POLICY queueForwardProgressPolicy;
WDFQUEUE readQueue;
NTSTATUS status = STATUS_SUCCESS;

WDF_IO_QUEUE_FORWARD_PROGRESS_POLICY_PAGINGIO_INIT(
    &queueForwardProgressPolicy,
    MAX_RESERVED_REQUESTS
    );
status = WdfIoQueueAssignForwardProgressPolicy(
    readQueue,
    &queueForwardProgressPolicy
    );

Requirements

Requirement	Value
Target Platform	Universal
Minimum KMDF version	1.9
Header	wdfio.h (include Wdf.h)

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