diff options
Diffstat (limited to 'mm/mprotect.c')
| -rw-r--r-- | mm/mprotect.c | 50 |
1 files changed, 24 insertions, 26 deletions
diff --git a/mm/mprotect.c b/mm/mprotect.c index ace93454ce8..44727811bf4 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -75,37 +75,35 @@ 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++; - } else if (IS_ENABLED(CONFIG_MIGRATION) && !pte_file(oldpte)) { + + 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); if (is_write_migration_entry(entry)) { |