Messages in this thread | | | Date | Fri, 27 Aug 2021 09:40:41 +0200 | From | Christoph Hellwig <> | Subject | Re: [GIT PULL] arm64 fix for 5.14 |
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On Thu, Aug 26, 2021 at 11:41:34AM -0700, Linus Torvalds wrote: > "pfn_valid()" is more about whether you can do a "pfn_to_page()" lookup on it. > > II get the feeling that the dma-mapping code should allow pages that > are PageReserved() to be mapped - they aren't "ram" in the kernel > sense. > > Perhaps also make sure it's not the zero page (which is > PageReserved(), but most definitely RAM). > > In a PC world that would be (for example) the legacy PCI space at > 0xa0000-0xfffff, but I could easily imagine other platforms having > other situations.
So what would be the correct check for "this is not actually page backed normal RAM"?
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