> dma_sync_single_for_{cpu,device} is what you would need in order to make
> a partial cache line invalidation. You would still need to unmap the
> same address+length pair that was used for the initial mapping otherwise
> the DMA-API debugging will rightfully complain.
But often you don't unmap it, you call dma_sync_single_for_device and
put it back into the ring.
Andrew
