On Thu, Oct 29, 2020 at 10:38:16AM +0100, Daniel Vetter wrote: > Hm so Jason and me discussed this, but e.g. the s390 is safe with with > just the pagetable locks. So we'd need two versions. > > The more practical problem is that I haven't found a reasonable way to > check that a passed in mmu_notifier is registered against the mm we're > working on, and without that check it feels a bit silly. But if you > see how to do that I think we can do an EXPORT_SYMBOL_GPL follow_pfn > which takes the notifier, and an __follow_pfn for s390 and similar > internal code which isn't exported. True, this is a bit of a mess. So maybe just rename it to __follow_pfn, proper documentation of the requirements and a switch to EXPORT_SYMBOL_GPL.
