Messages in this thread | | | Date | Sun, 7 Apr 2019 08:59:23 +0200 | From | Christoph Hellwig <> | Subject | Re: [PATCH 02/21] arm64/iommu: improve mmap bounds checking |
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On Fri, Apr 05, 2019 at 06:30:52PM +0100, Robin Murphy wrote: > On 27/03/2019 08:04, Christoph Hellwig wrote: >> The nr_pages checks should be done for all mmap requests, not just those >> using remap_pfn_range. > > Hmm, the logic in iommu_dma_mmap() inherently returns an error for the "off > >= nr_pages" case already. It's also supposed to be robust against the > "vma_pages(vma) > nr_pages - off" condition, although by making the partial > mapping and treating it as a success, rather than doing nothing and > returning an error. What's the exact motivation here?
Have one error check at the front of the function that is identical to the mmap checks in the other dma_map_ops instances so that:
a) we get the same error behavior for partial requests everywhere b) we can lift these checks into common code in the next round.
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