Re: [PATCH 12/21] dma-iommu: factor atomic pool allocations into helpers

[Robin Murphy]

On 18/04/2019 17:35, Christoph Hellwig wrote:
> On Thu, Apr 18, 2019 at 04:06:56PM +0100, Robin Murphy wrote:
> > OK, I'm still looking at mmap and get_sgtable, but for now I've pushed out
> > a partial branch that consolidates alloc and free in a way which makes
> > sense to me:
> >
> >    git://linux-arm.org/linux-rm  dma/rework
> >
> > Please let me know what you think.
>
>  From a very high level POV this looks ok, but sometimes a bit to
> convoluted to me.  The major issue why I went with the version I posted
> is that I can cleanly ifdef out the remap code in just a few sections.
> In this version it is spread out a lot more, and the use of IS_ENABLED
> means that we'd need a lot more stubs for functionality that won't
> ever be called but needs to be compilable.

What functionality do you have planned in that regard? I did do a quick 
build test of my arm64 config with DMA_DIRECT_REMAP hacked out, and 
dma-iommu.o appeared to link OK (although other bits of arm64 and 
dma-direct didn't, as expected). I will try x86 with IOMMU_DMA to make 
sure, though.

Robin.