NDK_FN_READ routine

The NdkRead (NDK_FN_READ) function posts a read request on an NDK queue pair (QP).

Syntax


NDK_FN_READ NdkRead;

NTSTATUS NdkRead(
  _In_      NDK_QP *pNdkQp,
  _In_opt_  PVOID RequestContext,
  _In_reads_(nSge) CONST NDK_SGE *pSgl,
  _In_      ULONG nSge,
  _In_      UINT64 RemoteAddress,
  _In_      UINT32 RemoteToken,
  _In_      ULONG Flags
)
{ ... }

Parameters

pNdkQp [in]

A pointer to an NDK queue pair (QP) object (NDK_QP).

RequestContext [in, optional]

A context value to be returned in the RequestContext member of the NDK_RESULT structure for this request.

pSgl

An array of SGE structures (NDK_SGE) that represent the buffers to place incoming data into.

nSge [in]

The number of SGE structures in the array that is specified in the pSgl parameter.

RemoteAddress [in]

A remote address to read from that is presented in the local host's byte order. The NDK consumer can add an offset to the remotely-provided value.

RemoteToken [in]

A remotely-provided memory token that is an opaque array of bytes from the NDK consumer.

Flags [in]

A bitwise OR of flags which specifies the operations that are allowed. The following flags are supported:

ValueMeaning
NDK_OP_FLAG_SILENT_SUCCESS
0x00000001

Indicates the successful completion of this request does not generate a completion event in the outbound completion queue. However, requests that fail do generate an event in the completion queue.

NDK_OP_FLAG_READ_FENCE
0x00000002

Indicates that all prior read requests must be complete before the hardware begins processing this request.

NDK_OP_FLAG_RDMA_READ_LOCAL_INVALIDATE
0x00000200

If this flag is set and the provider also reports NDK_ADAPTER_FLAG_RDMA_READ_LOCAL_INVALIDATE_SUPPORTED adapter capability in the NDK_ADAPTER_INFO structure, successful completion of the NdkRead function means that the first buffer specified in the pSgl parameter is invalidated. Unsuccessful completion leaves the buffer and token in an undefined state. This flag is ignored if the provider does not report NDK_ADAPTER_FLAG_RDMA_READ_LOCAL_INVALIDATE_SUPPORTED adapter capability in the NDK_ADAPTER_INFO structure.

Note  This flag is supported only in NDKPI 1.2 (Windows Server 2012 R2) and later.

NDK_OP_FLAG_DEFER
0x00000200

Indicates to the NDK provider that it may defer indicating the request to hardware for processing. For more information about this flag, see NDKPI Deferred Processing Scheme.

Note  This flag is supported only in NDKPI 1.2 (Windows Server 2012 R2) and later.

 

Return value

The NdkRead function returns one of the following NTSTATUS codes.

Return codeDescription
STATUS_SUCCESS

The request was posted successfully. A completion entry will be queued to the CQ when the work request is completed.

STATUS_CONNECTION_INVALID

The QP is not connected.

STATUS_REMOTE_RESOURCES

The request tried to read beyond the size of the remote memory.

Other status codes

An error occurred.

 

Remarks

NdkRead posts a read request on a queue pair (QP).

Requirements

Minimum supported client

None supported

Minimum supported server

Windows Server 2012

Version

Supported in NDIS 6.30 and later.

Header

Ndkpi.h (include Ndkpi.h)

IRQL

<=DISPATCH_LEVEL

See also

NDK_FN_ARM_CQ
NDK_ADAPTER_INFO
NDK_QP
NDK_RESULT
NDK_SGE
NDKPI Deferred Processing Scheme
NDKPI Work Request Posting Requirements

 

 

Send comments about this topic to Microsoft

Show:
© 2014 Microsoft