Messages in this thread | | | Date | Wed, 10 Sep 2008 01:49:37 +0900 | Subject | RE: [PATCH 1/4] add is_buffer_dma_capable helper function | From | FUJITA Tomonori <> |
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On Tue, 9 Sep 2008 09:17:05 -0700 "Luck, Tony" <tony.luck@intel.com> wrote:
> +static inline int is_buffer_dma_capable(u64 mask, dma_addr_t addr, size_t size) > +{ > + return addr + size <= mask; > +} > > Do we care about wrap-around (e.g. addr=0xffffffffffffffff size=2)?
We could do something like:
return addr < mask && addr + size <= mask;
But such wrap-around can happen only with a buggy IOMMU implementation. A driver will does DMA from 0xffffffffffffffff to 0x1. Even if this function does the right thing in such case, we will be dead?
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