Re: [PATCH] ARC: fix broken noncoherent cache ops

[Christoph Hellwig]

On Tue, Jul 24, 2018 at 05:13:02PM +0300, Eugeniy Paltsev wrote:
> All DMA devices on ARC haven't worked with SW cache control
> since commit a8eb92d02dd7 ("arc: fix arc_dma_{map,unmap}_page")
> This happens because we don't check direction argument at all in
> new implementation. Fix that.
> 
> Fixies: commit a8eb92d02dd7 ("arc: fix arc_dma_{map,unmap}_page")
> Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>

Looks sensible.  Might be worth explaining that ARC can speculate
into the areas under DMA, which is why this is required.