1 files changed, 34 insertions, 44 deletions

diff --git a/mm/page_table_check.c b/mm/page_table_check.c
index 509c6ef8de40..4eeca782b888 100644
--- a/mm/page_table_check.c
+++ b/mm/page_table_check.c
@@ -62,24 +62,20 @@ static struct page_table_check *get_page_table_check(struct page_ext *page_ext)
  */
 static void page_table_check_clear(unsigned long pfn, unsigned long pgcnt)
 {
+	struct page_ext_iter iter;
 	struct page_ext *page_ext;
 	struct page *page;
-	unsigned long i;
 	bool anon;
 
 	if (!pfn_valid(pfn))
 		return;
 
 	page = pfn_to_page(pfn);
-	page_ext = page_ext_get(page);
-
-	if (!page_ext)
-		return;
-
 	BUG_ON(PageSlab(page));
 	anon = PageAnon(page);
 
-	for (i = 0; i < pgcnt; i++) {
+	rcu_read_lock();
+	for_each_page_ext(page, pgcnt, page_ext, iter) {
 		struct page_table_check *ptc = get_page_table_check(page_ext);
 
 		if (anon) {
@@ -89,9 +85,8 @@ static void page_table_check_clear(unsigned long pfn, unsigned long pgcnt)
 			BUG_ON(atomic_read(&ptc->anon_map_count));
 			BUG_ON(atomic_dec_return(&ptc->file_map_count) < 0);
 		}
-		page_ext = page_ext_next(page_ext);
 	}
-	page_ext_put(page_ext);
+	rcu_read_unlock();
 }
 
 /*
@@ -102,24 +97,20 @@ static void page_table_check_clear(unsigned long pfn, unsigned long pgcnt)
 static void page_table_check_set(unsigned long pfn, unsigned long pgcnt,
 				 bool rw)
 {
+	struct page_ext_iter iter;
 	struct page_ext *page_ext;
 	struct page *page;
-	unsigned long i;
 	bool anon;
 
 	if (!pfn_valid(pfn))
 		return;
 
 	page = pfn_to_page(pfn);
-	page_ext = page_ext_get(page);
-
-	if (!page_ext)
-		return;
-
 	BUG_ON(PageSlab(page));
 	anon = PageAnon(page);
 
-	for (i = 0; i < pgcnt; i++) {
+	rcu_read_lock();
+	for_each_page_ext(page, pgcnt, page_ext, iter) {
 		struct page_table_check *ptc = get_page_table_check(page_ext);
 
 		if (anon) {
@@ -129,9 +120,8 @@ static void page_table_check_set(unsigned long pfn, unsigned long pgcnt,
 			BUG_ON(atomic_read(&ptc->anon_map_count));
 			BUG_ON(atomic_inc_return(&ptc->file_map_count) < 0);
 		}
-		page_ext = page_ext_next(page_ext);
 	}
-	page_ext_put(page_ext);
+	rcu_read_unlock();
 }
 
 /*
@@ -140,24 +130,19 @@ static void page_table_check_set(unsigned long pfn, unsigned long pgcnt,
  */
 void __page_table_check_zero(struct page *page, unsigned int order)
 {
+	struct page_ext_iter iter;
 	struct page_ext *page_ext;
-	unsigned long i;
 
 	BUG_ON(PageSlab(page));
 
-	page_ext = page_ext_get(page);
-
-	if (!page_ext)
-		return;
-
-	for (i = 0; i < (1ul << order); i++) {
+	rcu_read_lock();
+	for_each_page_ext(page, 1 << order, page_ext, iter) {
 		struct page_table_check *ptc = get_page_table_check(page_ext);
 
 		BUG_ON(atomic_read(&ptc->anon_map_count));
 		BUG_ON(atomic_read(&ptc->file_map_count));
-		page_ext = page_ext_next(page_ext);
 	}
-	page_ext_put(page_ext);
+	rcu_read_unlock();
 }
 
 void __page_table_check_pte_clear(struct mm_struct *mm, pte_t pte)
@@ -196,9 +181,8 @@ EXPORT_SYMBOL(__page_table_check_pud_clear);
 /* Whether the swap entry cached writable information */
 static inline bool swap_cached_writable(swp_entry_t entry)
 {
-	return is_writable_device_exclusive_entry(entry) ||
-	    is_writable_device_private_entry(entry) ||
-	    is_writable_migration_entry(entry);
+	return is_writable_device_private_entry(entry) ||
+	       is_writable_migration_entry(entry);
 }
 
 static inline void page_table_check_pte_flags(pte_t pte)
@@ -234,33 +218,39 @@ static inline void page_table_check_pmd_flags(pmd_t pmd)
 		WARN_ON_ONCE(swap_cached_writable(pmd_to_swp_entry(pmd)));
 }
 
-void __page_table_check_pmd_set(struct mm_struct *mm, pmd_t *pmdp, pmd_t pmd)
+void __page_table_check_pmds_set(struct mm_struct *mm, pmd_t *pmdp, pmd_t pmd,
+		unsigned int nr)
 {
+	unsigned long stride = PMD_SIZE >> PAGE_SHIFT;
+	unsigned int i;
+
 	if (&init_mm == mm)
 		return;
 
 	page_table_check_pmd_flags(pmd);
 
-	__page_table_check_pmd_clear(mm, *pmdp);
-	if (pmd_user_accessible_page(pmd)) {
-		page_table_check_set(pmd_pfn(pmd), PMD_SIZE >> PAGE_SHIFT,
-				     pmd_write(pmd));
-	}
+	for (i = 0; i < nr; i++)
+		__page_table_check_pmd_clear(mm, *(pmdp + i));
+	if (pmd_user_accessible_page(pmd))
+		page_table_check_set(pmd_pfn(pmd), stride * nr, pmd_write(pmd));
 }
-EXPORT_SYMBOL(__page_table_check_pmd_set);
+EXPORT_SYMBOL(__page_table_check_pmds_set);
 
-void __page_table_check_pud_set(struct mm_struct *mm, pud_t *pudp, pud_t pud)
+void __page_table_check_puds_set(struct mm_struct *mm, pud_t *pudp, pud_t pud,
+		unsigned int nr)
 {
+	unsigned long stride = PUD_SIZE >> PAGE_SHIFT;
+	unsigned int i;
+
 	if (&init_mm == mm)
 		return;
 
-	__page_table_check_pud_clear(mm, *pudp);
-	if (pud_user_accessible_page(pud)) {
-		page_table_check_set(pud_pfn(pud), PUD_SIZE >> PAGE_SHIFT,
-				     pud_write(pud));
-	}
+	for (i = 0; i < nr; i++)
+		__page_table_check_pud_clear(mm, *(pudp + i));
+	if (pud_user_accessible_page(pud))
+		page_table_check_set(pud_pfn(pud), stride * nr, pud_write(pud));
 }
-EXPORT_SYMBOL(__page_table_check_pud_set);
+EXPORT_SYMBOL(__page_table_check_puds_set);
 
 void __page_table_check_pte_clear_range(struct mm_struct *mm,
 					unsigned long addr,