Re: [RFC/RFT PATCH 1/2] dma-contiguous: Simplify dma_*_from_contiguous() function calls

[Robin Murphy]

On 30/04/2019 11:56, Christoph Hellwig wrote:
> So while I really, really like this cleanup it turns out it isn't
> actually safe for arm :(  arm remaps the CMA allocation in place
> instead of using a new mapping, which can be done because they don't
> share PMDs with the kernel.
>
> So we'll probably need a __dma_alloc_from_contiguous version with
> an additional bool fallback argument - everyone but arms uses
> dma_alloc_from_contiguous as in your patch, just arm will get the
> non-fallback one.

Or we even just implement dma_{alloc,free}_contiguous() as a wrapper 
around the existing APIs so that users can be thoroughly checked and 
converted one-by-one.

Robin.