mm/pagemap: recognize uffd-wp bit for shmem/hugetlbfs

This requires the pagemap code to be able to recognize the newly
introduced swap special pte for uffd-wp, meanwhile the general case for
hugetlb that we recently start to support.  It should make pagemap uffd-wp
support complete.

Link: https://lkml.kernel.org/r/20220405014923.15047-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index a843d13..2d04e34 100644 (file)
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1421,6 +1421,8 @@ static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm,
                migration = is_migration_entry(entry);
                if (is_pfn_swap_entry(entry))
                        page = pfn_swap_entry_to_page(entry);
+               if (pte_marker_entry_uffd_wp(entry))
+                       flags |= PM_UFFD_WP;
        }
 
        if (page && !PageAnon(page))
@@ -1556,10 +1558,15 @@ static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask,
                if (page_mapcount(page) == 1)
                        flags |= PM_MMAP_EXCLUSIVE;
 
+               if (huge_pte_uffd_wp(pte))
+                       flags |= PM_UFFD_WP;
+
                flags |= PM_PRESENT;
                if (pm->show_pfn)
                        frame = pte_pfn(pte) +
                                ((addr & ~hmask) >> PAGE_SHIFT);
+       } else if (pte_swp_uffd_wp_any(pte)) {
+               flags |= PM_UFFD_WP;
        }
 
        for (; addr != end; addr += PAGE_SIZE) {