diff --git a/mm/ksm.c b/mm/ksm.c index 0f5b2bba4ef0..8e53666bc7b0 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -608,47 +608,6 @@ static inline bool ksm_test_exit(struct mm_struct *mm) return atomic_read(&mm->mm_users) == 0; } -static int break_ksm_pmd_entry(pmd_t *pmd, unsigned long addr, unsigned long next, - struct mm_walk *walk) -{ - struct page *page = NULL; - spinlock_t *ptl; - pte_t *pte; - pte_t ptent; - int ret; - - pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); - if (!pte) - return 0; - ptent = ptep_get(pte); - if (pte_present(ptent)) { - page = vm_normal_page(walk->vma, addr, ptent); - } else if (!pte_none(ptent)) { - swp_entry_t entry = pte_to_swp_entry(ptent); - - /* - * As KSM pages remain KSM pages until freed, no need to wait - * here for migration to end. - */ - if (is_migration_entry(entry)) - page = pfn_swap_entry_to_page(entry); - } - /* return 1 if the page is an normal ksm page or KSM-placed zero page */ - ret = (page && PageKsm(page)) || is_ksm_zero_pte(ptent); - pte_unmap_unlock(pte, ptl); - return ret; -} - -static const struct mm_walk_ops break_ksm_ops = { - .pmd_entry = break_ksm_pmd_entry, - .walk_lock = PGWALK_RDLOCK, -}; - -static const struct mm_walk_ops break_ksm_lock_vma_ops = { - .pmd_entry = break_ksm_pmd_entry, - .walk_lock = PGWALK_WRLOCK, -}; - /* * We use break_ksm to break COW on a ksm page by triggering unsharing, * such that the ksm page will get replaced by an exclusive anonymous page. @@ -665,16 +624,26 @@ static const struct mm_walk_ops break_ksm_lock_vma_ops = { static int break_ksm(struct vm_area_struct *vma, unsigned long addr, bool lock_vma) { vm_fault_t ret = 0; - const struct mm_walk_ops *ops = lock_vma ? - &break_ksm_lock_vma_ops : &break_ksm_ops; + + if (lock_vma) + vma_start_write(vma); do { - int ksm_page; + bool ksm_page = false; + struct folio_walk fw; + struct folio *folio; cond_resched(); - ksm_page = walk_page_range_vma(vma, addr, addr + 1, ops, NULL); - if (WARN_ON_ONCE(ksm_page < 0)) - return ksm_page; + folio = folio_walk_start(&fw, vma, addr, + FW_MIGRATION | FW_ZEROPAGE); + if (folio) { + /* Small folio implies FW_LEVEL_PTE. */ + if (!folio_test_large(folio) && + (folio_test_ksm(folio) || is_ksm_zero_pte(fw.pte))) + ksm_page = true; + folio_walk_end(&fw, vma); + } + if (!ksm_page) return 0; ret = handle_mm_fault(vma, addr,