Re: [PATCH] sparc: use asm-generic/scatterlist.h

[Arnd Bergmann <arnd@arndb.de>]

On Tuesday 02 March 2010, FUJITA Tomonori wrote:
> Yeah, but IIRC, Alpha, x86_64 GART, parisc, and IA64 don't have
> CONFIG_ option for IOMMU virtual merging. I prefer to avoid to adding
> something like CONFIG_HAVE_IOMMU_VMERGE for them. If we add
> CONFIG_HAVE_IOMMU_VMERGE to them, it's a bit strange not to add the
> feature to disable virtual merging for them (I guess GART already has
> the feature though).

While I think the runtime feature (actually a workaround for broken device
drivers) should be consistently used on all architectures, or removed
entirely, it's orthogonal to this discussion. I'm sure you'll come
up with a reasonable name for a new option if you introduce one.
CONFIG_HAVE_IOMMU_VMERGE and CONFIG_NEED_SG_DMA_LENGTH both seem ok
to me.

> Actually, I want to use dma_length on all the architectures (if nobody
> complains).

Fine with me as well. It wastes a small amount of memory but makes
the code more consistent.

	Arnd