Re: [PATCH v3 3/4] arm64: Add IOMMU dma_ops

[Catalin Marinas <catalin.marinas-5wv7dgnIgG8@public.gmane.org>]

On Wed, Jul 15, 2015 at 05:27:22PM +0100, Robin Murphy wrote:
> On 15/07/15 10:31, Catalin Marinas wrote:
> >On Fri, Jul 10, 2015 at 08:19:34PM +0100, Robin Murphy wrote:
> >>+			if (iommu_dma_mapping_error(dev, *handle)) {
> >>+				if (coherent)
> >>+					__free_pages(page, get_order(size));
> >>+				else
> >>+					__free_from_pool(addr, size);
> >>+				addr = NULL;
> >>+			}
> >>+		}
> >>+	}
> >>+	return addr;
> >>+}
> >
> >In the second case here (!__GFP_WAIT), do we do any cache maintenance? I
> >can't see it and it's needed for the !coherent case.
> 
> In the atomic non-coherent case, we're stealing from the atomic pool, so
> addr is already a non-cacheable alias (and alloc_from_pool does memset(0)
> through that). That shouldn't need anything extra, right?

You are right, we already flushed the cache for the atomic pool when we
allocated it in atomic_pool_init().

-- 
Catalin