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-rw-r--r--mm/mprotect.c48
1 files changed, 23 insertions, 25 deletions
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 3312166..4472781 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -75,36 +75,34 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
oldpte = *pte;
if (pte_present(oldpte)) {
pte_t ptent;
- bool updated = false;
- if (!prot_numa) {
- ptent = ptep_modify_prot_start(mm, addr, pte);
- if (pte_numa(ptent))
- ptent = pte_mknonnuma(ptent);
- ptent = pte_modify(ptent, newprot);
- /*
- * Avoid taking write faults for pages we
- * know to be dirty.
- */
- if (dirty_accountable && pte_dirty(ptent) &&
- (pte_soft_dirty(ptent) ||
- !(vma->vm_flags & VM_SOFTDIRTY)))
- ptent = pte_mkwrite(ptent);
- ptep_modify_prot_commit(mm, addr, pte, ptent);
- updated = true;
- } else {
+ /*
+ * Avoid trapping faults against the zero or KSM
+ * pages. See similar comment in change_huge_pmd.
+ */
+ if (prot_numa) {
struct page *page;
page = vm_normal_page(vma, addr, oldpte);
- if (page && !PageKsm(page)) {
- if (!pte_numa(oldpte)) {
- ptep_set_numa(mm, addr, pte);
- updated = true;
- }
- }
+ if (!page || PageKsm(page))
+ continue;
+
+ /* Avoid TLB flush if possible */
+ if (pte_protnone(oldpte))
+ continue;
}
- if (updated)
- pages++;
+
+ ptent = ptep_modify_prot_start(mm, addr, pte);
+ ptent = pte_modify(ptent, newprot);
+
+ /* Avoid taking write faults for known dirty pages */
+ if (dirty_accountable && pte_dirty(ptent) &&
+ (pte_soft_dirty(ptent) ||
+ !(vma->vm_flags & VM_SOFTDIRTY))) {
+ ptent = pte_mkwrite(ptent);
+ }
+ ptep_modify_prot_commit(mm, addr, pte, ptent);
+ pages++;
} else if (IS_ENABLED(CONFIG_MIGRATION)) {
swp_entry_t entry = pte_to_swp_entry(oldpte);

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