linux-next: build failure after merge of the final tree (net-next tree related)

[Benjamin Herrenschmidt]

> > I think the powerpc port is at fault here.
> > 
> > Part of being able to advertise ISA_DMA_API is providing isa_virt_to_bus().

Hrm, that's ancient gunk, I'll have to dig. We potentially can support
ISA devices DMA'ing from an ISA bridge... but via the iommu, which means
isa_virt_to_bus is a non-starter.

But then, do we really care ? IE. Is there single device that actually
requires ISA_DMA_API and that is expected to work on any currently
supported powerpc hw ? :-)

We don't even support PReP anymore, so that leaves us with what ?

Anybody has an objection to turning ISA_DMA_API off ?

Cheers,
Ben.