Messages in this thread | | | Subject | Re: [PATCH 02/21] arm64/iommu: improve mmap bounds checking | From | Robin Murphy <> | Date | Tue, 9 Apr 2019 16:12:51 +0100 |
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On 07/04/2019 07:59, Christoph Hellwig wrote: > 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. >
Fair enough, but in that case why isn't the dma_mmap_from_coherent() path also covered?
Robin.
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