Messages in this thread | | | From | Ard Biesheuvel <> | Date | Thu, 21 Apr 2022 10:05:49 +0200 | Subject | Re: [PATCH 07/10] crypto: Use ARCH_DMA_MINALIGN instead of ARCH_KMALLOC_MINALIGN |
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On Thu, 21 Apr 2022 at 09:20, Christoph Hellwig <hch@infradead.org> wrote: > > Btw, there is another option: Most real systems already require having > swiotlb to bounce buffer in some cases. We could simply force bounce > buffering in the dma mapping code for too small or not properly aligned > transfers and just decrease the dma alignment.
Strongly agree. As I pointed out before, we'd only need to do this for misaligned, non-cache coherent inbound DMA, and we'd only have to worry about performance regressions, not data corruption issues. And given the natural alignment of block I/O, and the fact that network drivers typically allocate and map their own RX buffers (which means they could reasonably be fixed if a performance bottleneck pops up), I think the risk for showstopper performance regressions is likely to be acceptable.
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