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-rw-r--r--mm/hugetlb.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 03cbb75bcb54..c0012b4a8eec 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4790,7 +4790,7 @@ again:
is_hugetlb_entry_hwpoisoned(entry))) {
swp_entry_t swp_entry = pte_to_swp_entry(entry);
- if (is_writable_migration_entry(swp_entry) && cow) {
+ if (!is_readable_migration_entry(swp_entry) && cow) {
/*
* COW mappings require pages in both
* parent and child to be set to read.
@@ -5190,6 +5190,8 @@ retry_avoidcopy:
set_huge_ptep_writable(vma, haddr, ptep);
return 0;
}
+ VM_BUG_ON_PAGE(PageAnon(old_page) && PageAnonExclusive(old_page),
+ old_page);
/*
* If the process that created a MAP_PRIVATE mapping is about to
@@ -6187,12 +6189,17 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
}
if (unlikely(is_hugetlb_entry_migration(pte))) {
swp_entry_t entry = pte_to_swp_entry(pte);
+ struct page *page = pfn_swap_entry_to_page(entry);
- if (is_writable_migration_entry(entry)) {
+ if (!is_readable_migration_entry(entry)) {
pte_t newpte;
- entry = make_readable_migration_entry(
- swp_offset(entry));
+ if (PageAnon(page))
+ entry = make_readable_exclusive_migration_entry(
+ swp_offset(entry));
+ else
+ entry = make_readable_migration_entry(
+ swp_offset(entry));
newpte = swp_entry_to_pte(entry);
set_huge_swap_pte_at(mm, address, ptep,
newpte, huge_page_size(h));