Re: [PATCH] dma-direct: avoid redundant memory sync for swiotlb

From: Christoph Hellwig
Date: Wed Apr 13 2022 - 12:44:58 EST


On Wed, Apr 13, 2022 at 02:10:56PM +0100, Robin Murphy wrote:
> Are you sure? AFAICS swiotlb_map() does the right thing, and
> dma_direct_{sync,unmap} are working off the DMA address, which is that of
> the bounce slot when SWIOTLB is involved (not least, how would the
> is_swiotlb_buffer() checks work otherwise?)

Yeah, actually this should be fine.