NDIS_BUFFER_TO_SPAN_PAGES (Windows Embedded CE 6.0)

1/6/2010

This macro determines how many physical pages of memory are being used to back a specified buffer.

Syntax

ULONG NDIS_BUFFER_TO_SPAN_PAGES(
  PNDIS_BUFFER _Buffer
);

Parameters

• _Buffer
  Specifies the buffer descriptor mapping the buffer.

Return Value

The return value is the Windows Embedded CE version, which is always 1.

Remarks

This macro is used by DMA drivers to determine how many physical discontiguities exist in a specified virtual buffer.

The NDIS_BUFFER_TO_SPAN_PAGES macro is defined as follows.

#define NDIS_BUFFER_TO_SPAN_PAGES(_Buffer)                  \
    (MmGetMdlByteCount(_Buffer)==0 ?                        \
                1 :                                         \
                (COMPUTE_PAGES_SPANNED(                     \
                        MmGetMdlVirtualAddress(_Buffer),    \
                        MmGetMdlByteCount(_Buffer))))

Requirements

See Also

Reference

Network Driver Macros
NDIS_BUFFER
NdisAllocateBuffer
NdisFreeBuffer
NdisBufferVirtualAddress

Concepts

Subordinate DMA Network Adapters