Re: [PATCH 05/67] dma-mapping: replace PCI_DMA_BUS_IS_PHYS with a flag in struct dma_map_ops

[Geert Uytterhoeven]

On Fri, Dec 29, 2017 at 9:18 AM, Christoph Hellwig <hch@xxxxxx> wrote:
> The current PCI_DMA_BUS_IS_PHYS decided if a dma implementation is bound
> by the dma mask in the device because it directly maps to a physical
> address range (modulo an offset in the device), or if it is virtualized
> by an iommu and can map any address (that includes virtual iommus like
> swiotlb).  The problem with this scheme is that it is per-architecture and
> not per dma_ops instance, and we are growing more and more setups that
> have multiple different dma operations in use on a single system, for
> which this scheme can't provide a correct answer.  Depending on the
> architecture that means we either get a false positive or false negative
> at the moment.
>
> This patch instead extents the is_phys flag in struct dma_map_ops that
> is currently only used by a few architectures to be used tree wide.
>
> Note that this means that we now need a struct device parent in the
> Scsi_Host or netdevice.  Every modern driver has these, but there might
> still be a few outdated legacy drivers out there, which now won't make
> an intelligent decision.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>

For m68k:
Acked-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

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                                -- Linus Torvalds