Re: [PATCH net v1 2/2] lan743x: boost performance: limit PCIe bandwidth requirement

[Andrew Lunn]

> 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