Messages in this thread | | | Date | Sat, 1 Dec 2018 17:56:10 +0100 | From | Christoph Hellwig <> | Subject | Re: [PATCH 1/9] dma-direct: provide page based alloc/free helpers |
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On Fri, Nov 30, 2018 at 07:04:41PM +0000, Robin Murphy wrote: > On 05/11/2018 12:19, Christoph Hellwig wrote: >> Some architectures support remapping highmem into DMA coherent >> allocations. To use the common code for them we need variants of >> dma_direct_{alloc,free}_pages that do not use kernel virtual addresses. > > FWIW it's as much about non-cacheable remapping of lowmem as it is about > highmem. Regardless, the diff looks OK to me.
Yes, but as long as you remap lowmem the current interface work ok, but once you have highmem a kernel virtual address doesn't cut it, and we need a page struct or physical address.
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