Messages in this thread | | | Date | Tue, 3 Oct 2017 09:07:52 +0200 | From | Christoph Hellwig <> | Subject | Re: [PATCH v3] dma-debug: fix incorrect pfn calculation |
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On Mon, Oct 02, 2017 at 06:30:41PM +0800, Miles Chen wrote: > ARCHs like metag and xtensa define their mappings (non-vmalloc and > non-linear) for dma allocation.
metag basically is a reimplementation of the vmalloc map mechanism that should be easy to consolidate into the common one :( xtensa has a weird remapping into a different segment, something that I vaguely remember mips used to support as well.
> These mapping types are architecture-dependent and should not be used > outside arch folders. So it is hard to check the mappings and convert > a virtual address to a correct pfn in lib/dam-debug.c > > How about recording only vmalloc (by is_vmalloc_addr()) and linear > address (by virt_addr_valid()) in lib/dma-debug? Since current > implementation is not correct for those ARCHs. > > if (!is_vmalloc_addr(addr) && !virt_addr_valid(addr)) > return; > > or
This looks like a good start, although I'm not sure I'd trust virt_addr_valid on every little arch. In the worse case we'll have to exclude offenders from supporting dma debug, so let's go with that version.
> > > > + entry->pfn = is_vmalloc_addr(virt) ? vmalloc_to_pfn(virt) : > > > > + page_to_pfn(virt_to_page(virt)); > > > > Please use normal if/else conditionsals: > > Is this for better readability? I'll send another patch for this.
Yes.
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