Re: [PATCH] x86-64: dma_ops for DMA mapping -K4

From: Muli Ben-Yehuda
Date: Fri Nov 18 2005 - 14:46:35 EST

On Thu, Nov 17, 2005 at 10:03:48PM +0000, Christoph Hellwig wrote:
> On Thu, Nov 17, 2005 at 03:16:22PM +0200, Muli Ben-Yehuda wrote:
> > Hi Andi,
> >
> > Here's the latest version of the dma_ops patch. The patch is against
> > Linus's tree as of yesterday and applies cleanly to
> > 2.6.15-rc1-git5. Tested on AMD64 and Intel EM64 (x366) with gart,
> > swiotlb, nommu and iommu=off. Please apply...
> Any chance you could move struct dma_mapping_ops to generic code and
> implement the dma_ operations ontop of them in linux/dma-mapping.h if
> the arch sets a WANT_DMA_MAPPING_OPS symbol? This kind of switch is
> duplicated in far too many architectures.

I'm looking at this now. PPC, IA64 and parisc have something like
this, as well as x86-64 with my patch applied. The others either have
dma_ops with completely different semantics or choose the dma ops
implementation at compile time. However, each arch needs a slightly
different definition of dma_mapping_ops - I'm not sure having one
definition catering to all archs is better than what we have now,
considering the DMA mapping implementation is inherently arch

Muli Ben-Yehuda |

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