Messages in this thread | | | Date | Wed, 30 Oct 2019 14:41:40 -0700 | From | Christoph Hellwig <> | Subject | Re: [PATCH v2 1/2] dma-direct: check for overflows on 32 bit DMA addresses |
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On Fri, Oct 18, 2019 at 01:00:43PM +0200, Nicolas Saenz Julienne wrote: > +#ifndef CONFIG_ARCH_DMA_ADDR_T_64BIT > + /* Check if DMA address overflowed */ > + if (min(addr, addr + size - 1) < > + __phys_to_dma(dev, (phys_addr_t)(min_low_pfn << PAGE_SHIFT))) > + return false; > +#endif
Would be nice to use IS_ENABLED and PFN_PHYS here, and I also think we need to use phys_to_dma to take care of the encryption bit. If you then also introduce an end variable we can make the whole thing actually look nice:
static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size) { dma_addr_t end = addr + size - 1;
if (!dev->dma_mask) return false;
if (!IS_ENABLED(CONFIG_ARCH_DMA_ADDR_T_64BIT) && min(addr, end) < phys_to_dma(dev, PFN_PHYS(min_low_pfn))) return false;
return end <= min_not_zero(*dev->dma_mask, dev->bus_dma_mask); }
Otherwise this looks sensible to me.
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