On Thu, May 05, 2022 at 04:34:36PM -0500, Alex Sierra wrote: > diff --git a/mm/memory.c b/mm/memory.c > index 76e3af9639d9..892c4cc54dc2 100644 > +++ b/mm/memory.c > @@ -621,6 +621,13 @@ struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, > if (is_zero_pfn(pfn)) > return NULL; > if (pte_devmap(pte)) > +/* > + * NOTE: Technically this should goto check_pfn label. However, page->_mapcount > + * is never incremented for device pages that are mmap through DAX mechanism > + * using pmem driver mounted into ext4 filesystem. When these pages are unmap, > + * zap_pte_range is called and vm_normal_page return a valid page with > + * page_mapcount() = 0, before page_remove_rmap is called. > + */ > return NULL; ? Where does this series cause device coherent to be returned? Wasn't the plan to not set pte_devmap() ? Jason
