Messages in this thread | | | Date | Mon, 13 Feb 2023 22:12:57 -0800 | From | Christoph Hellwig <> | Subject | Re: [PATCH v2 4/4] crypto: starfive - Add hash and HMAC support |
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On Thu, Feb 09, 2023 at 05:43:34PM +0800, Herbert Xu wrote: > On Thu, Feb 09, 2023 at 09:33:06AM +0000, JiaJie Ho wrote: > > > > The DMA can only support 32-bit addressing. > > So, I am copying everything in case kernel allocated memory region >32-bit for a user app. > > Does your hardware support scatter-and-gather? If so you should > at least allocate individual pages rather than one contiguous buffer. > > Then you can allocate them on-demand rather than before-hand. > > It would also be nice to not do the copy if the input you were > given was in low memory (and contiguous if your hardware doesn't > do SG).
All of that is done by the DMA API, or more specifically swiotlb and does not need to be duplicated in individual drivers.
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