ScsiPortWmiDispatchFunction function (scsiwmi.h)

Article
10/21/2021

The ScsiPortWmiDispatchFunction routine is a dispatch routine for miniport drivers that support WMI.

Note The SCSI port driver and SCSI miniport driver models may be altered or unavailable in the future. Instead, we recommend using the Storport driver and Storport miniport driver models.

Syntax

BOOLEAN ScsiPortWmiDispatchFunction(
  [in] PSCSI_WMILIB_CONTEXT     WmiLibInfo,
  [in] UCHAR                    MinorFunction,
  [in] PVOID                    DeviceContext,
  [in] PSCSIWMI_REQUEST_CONTEXT RequestContext,
  [in] PVOID                    DataPath,
  [in] ULONG                    BufferSize,
  [in] PVOID                    Buffer
);

Parameters

[in] WmiLibInfo

Pointer to a SCSI_WMILIB_CONTEXT structure that contains registration information for a miniport driver's data blocks and event blocks and defines entry points for the miniport driver's WMI library callback routines.

[in] MinorFunction

Indicates the WMI action to perform. The miniport driver sets MinorFunction to Srb->WmiSubFunction from the input SRB.

[in] DeviceContext

Pointer to a miniport driver-defined context value. The port driver will pass DeviceContext to the miniport driver's HwScsiWmiXxx callback routine. This value would typically point to a HW_DEVICE_EXTENSION structure.

[in] RequestContext

Pointer to a SCSIWMI_REQUEST_CONTEXT structure that contains context information for the WMI SRB. If the SRB can pend, the miniport driver must allocate this structure from the SRB extension because the request context must remain valid until after ScsiPortWmiPostProcess returns with the final SRB return status and buffer size. ScsiPortWmiDispatchFunction will pass RequestContext to the miniport driver's callback routine that processes this request.

[in] DataPath

Pointer to a GUID that represents the data block associated with the request. The miniport driver sets DataPath to Srb->DataPath from the input SRB.

[in] BufferSize

Specifies the size in bytes of the data buffer. The miniport driver sets BufferSize to Srb->DataTransferLength from the input SRB.

[in] Buffer

Pointer to the data buffer. The miniport driver sets Buffer to Srb->DataBuffer from the input SRB.

Return value

ScsiPortWmiDispatchFunction returns TRUE if the request is pending, or FALSE if the request was completed.

Remarks

When a miniport driver receives an SRB in which the Function member is set to SRB_FUNCTION_WMI, it calls ScsiPortWmiDispatchFunction with request parameters, including a pointer to an initialized SCSI_WMILIB_CONTEXT structure. This structure contains information about the miniport driver's data blocks and event blocks and defines entry points for the miniport driver's HwScsiWmiXxx callback routines.

ScsiPortWmiDispatchFunction confirms that the SRB is a WMI request and determines whether the block specified by the request is valid for the miniport driver. If these conditions are met, ScsiPortWmiDispatchFunction processes the SRB by calling the appropriate HwScsiWmiXxx entry point in the miniport driver's SCSI_WMILIB_CONTEXT structure. If the miniport driver does not define an entry point for an optional HwScsiWmiXxx routine, the port driver handles the request.

In either case, after ScsiPortWmiDispatchFunction returns, the miniport driver should do the following for requests that it does not pend:

Set Srb->DataTransferLength to the value returned by ScsiPortWmiGetReturnSize
Set Srb->SrbStatus to the value returned by ScsiPortWmiGetReturnStatus
Call ScsiPortNotification with RequestComplete and again with NextRequest

Requirements

Requirement	Value
Target Platform	Desktop
Header	scsiwmi.h (include Miniport.h, Scsi.h)