[PATCH v7 20/23] mm/pagemap: Recognize uffd-wp bit for shmem/hugetlbfs

Peter Xu
2022-03-04T05:20:27Z

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.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
fs/proc/task_mmu.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 2c48b1eaaa9c..46e5896b82d2 100644
--- 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) {
--
2.32.0