NdisFlushBuffer

This function flushes the memory region described by a specified buffer descriptor from all processor caches.

At a Glance

Syntax

VOID NdisFlushBuffer( IN PNDIS_BUFFER Buffer,
IN BOOLEAN WriteToDevice );

Parameters

Buffer

Pointer to a buffer description mapping a buffer from which or into which data is transferred as a busmaster DMA operation.

WriteToDevice

Specifies TRUE if the NIC driver calls this function to flush a buffer before making a transfer from host memory to the NIC.

If the NIC driver specifies FALSE, it must ensure the buffer begins and ends on a cache-line boundary.

Remarks

Drivers of busmaster DMA NICs call this function to maintain data integrity in shared memory. Flushing the buffer ensures coherency between the host memory cache and processor physical memory before a DMA transfer to or from the network interface card.

The driver flushes such a buffer when data that it shares with its NIC might be cached. For any transfer between host memory and a busmaster DMA NIC, the miniport must flush the buffer before the transfer starts. Such a driver also must ensure that host memory is not accessed until the transfer completes.

A driver that calls this function runs at IRQL <= DISPATCH_LEVEL.