wp_clean_pmd_entry() need not check pmd_trans_unstable() or pmd_none(), wp_clean_pud_entry() need not check pud_trans_unstable() or pud_none(): it's just the ACTION_CONTINUE when trans_huge or devmap that's needed to prevent splitting, and we're hoping to remove pmd_trans_unstable(). Is that PUD #ifdef necessary? Maybe some configs are missing a stub. Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx> --- mm/mapping_dirty_helpers.c | 34 +++++++++------------------------- 1 file changed, 9 insertions(+), 25 deletions(-) diff --git a/mm/mapping_dirty_helpers.c b/mm/mapping_dirty_helpers.c index e1eb33f49059..87b4beeda4fa 100644 --- a/mm/mapping_dirty_helpers.c +++ b/mm/mapping_dirty_helpers.c @@ -128,19 +128,11 @@ static int wp_clean_pmd_entry(pmd_t *pmd, unsigned long addr, unsigned long end, { pmd_t pmdval = pmdp_get_lockless(pmd); - if (!pmd_trans_unstable(&pmdval)) - return 0; - - if (pmd_none(pmdval)) { - walk->action = ACTION_AGAIN; - return 0; - } - - /* Huge pmd, present or migrated */ - walk->action = ACTION_CONTINUE; - if (pmd_trans_huge(pmdval) || pmd_devmap(pmdval)) + /* Do not split a huge pmd, present or migrated */ + if (pmd_trans_huge(pmdval) || pmd_devmap(pmdval)) { WARN_ON(pmd_write(pmdval) || pmd_dirty(pmdval)); - + walk->action = ACTION_CONTINUE; + } return 0; } @@ -156,23 +148,15 @@ static int wp_clean_pmd_entry(pmd_t *pmd, unsigned long addr, unsigned long end, static int wp_clean_pud_entry(pud_t *pud, unsigned long addr, unsigned long end, struct mm_walk *walk) { +#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD pud_t pudval = READ_ONCE(*pud); - if (!pud_trans_unstable(&pudval)) - return 0; - - if (pud_none(pudval)) { - walk->action = ACTION_AGAIN; - return 0; - } - -#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD - /* Huge pud */ - walk->action = ACTION_CONTINUE; - if (pud_trans_huge(pudval) || pud_devmap(pudval)) + /* Do not split a huge pud */ + if (pud_trans_huge(pudval) || pud_devmap(pudval)) { WARN_ON(pud_write(pudval) || pud_dirty(pudval)); + walk->action = ACTION_CONTINUE; + } #endif - return 0; } -- 2.35.3