Messages in this thread | | | Date | Fri, 20 Apr 2018 05:46:25 -0700 | From | Christoph Hellwig <> | Subject | Re: [PATCH 4/8] dma-buf: add peer2peer flag |
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On Fri, Apr 20, 2018 at 12:44:01PM +0200, Christian König wrote: > > > What we need is an sg_alloc_table_from_resources(dev, resources, > > > num_resources) which does the handling common to all drivers. > > A structure that contains > > > > {page,offset,len} + {dma_addr+dma_len} > > > > is not a good container for storing > > > > {virt addr, dma_addr, len} > > > > no matter what interface you build arond it. > > Why not? I mean at least for my use case we actually don't need the virtual > address.
If you don't need the virtual address you need scatterlist even list.
> What we need is {dma_addr+dma_len} in a consistent interface which can come > from both {page,offset,len} as well as {resource, len}.
Ok.
> What I actually don't need is separate handling for system memory and > resources, but that would we get exactly when we don't use sg_table.
At the very lowest level they will need to be handled differently for many architectures, the questions is at what point we'll do the branching out.
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