[ oops, I should have looked at the replies first, now I see Ben already
had the same thing to say about #3... ]
On 27/09/18 14:49, Christoph Hellwig wrote:
On Thu, Sep 27, 2018 at 11:50:14AM +1000, Benjamin Herrenschmidt wrote:
- * to be able to satisfy them - either by not supporting more physical
- * memory, or by providing a ZONE_DMA32. If neither is the case, the
- * architecture needs to use an IOMMU instead of the direct mapping.
- */
- if (mask < phys_to_dma(dev, DMA_BIT_MASK(32)))
+ u64 min_mask;
+
+ if (IS_ENABLED(CONFIG_ZONE_DMA))
+ min_mask = DMA_BIT_MASK(ARCH_ZONE_DMA_BITS);
+ else
+ min_mask = min_t(u64, DMA_BIT_MASK(32),
+ (max_pfn - 1) << PAGE_SHIFT);
+
+ if (mask >= phys_to_dma(dev, min_mask))
return 0;
nitpick ... to be completely "correct", I would have written
if (IS_ENABLED(CONFIG_ZONE_DMA))
min_mask = DMA_BIT_MASK(ARCH_ZONE_DMA_BITS);
else
min_mask = DMA_BIT_MASK(32);
min_mask = min_t(u64, min_mask, (max_pfn - 1) << PAGE_SHIFT);
In "theory" it's also ok to have a mask < ZONE_DMA_BITS as long as it's
big enough to fit all memory :-)
Yeah, we could do that.
FWIW I like it even if just for looking slightly more readable. With
that fixup,
Reviewed-by: Robin Murphy <robin.mur...@arm.com>
