On Wed, Feb 02, 2022 at 10:33:04PM +0800, Muchun Song wrote: > page_vma_mapped_walk() is supposed to check if a page is mapped into a vma. > However, not all page frames (e.g. PFN_DEV) have a associated struct page > with it. There is going to be some duplicate codes similar with this function > if someone want to check if a pfn (without a struct page) is mapped into a > vma. So add support for checking if a pfn is mapped into a vma. In the next > patch, the dax will use this new feature.
I'm coming to more or less the same solution for fixing the bug in page_mapped_in_vma(). If you call it with a head page, it will look for any page in the THP instead of the precise page. I think we can do a fairly significant simplification though, so I'm going to go off and work on that next ...
