Re: [PATCH V6 1/3] dma-mapping: Introduce device_is_coherent() as ahelper

[Christoph Hellwig]

On Fri, Sep 22, 2017 at 02:44:51PM +0100, Robin Murphy wrote:
> Not quite - I mean instead of adding an ops->device_is_coherent callback
> (which cannot really have a safe fallback value either way) and trying
> to enforce that dma_get_cache_alignment() should be the only valid
> caller, just add an ops->get_cache_alignment callback directly.

Exactly - and then fall back to ARCH_DMA_MINALIGN/1 if the ops vector
is not provided, to keep the existing behavior.