1 files changed, 26 insertions, 36 deletions

diff --git a/mm/mapping_dirty_helpers.c b/mm/mapping_dirty_helpers.c
index 2c7d03675903..2f8829b3541a 100644
--- a/mm/mapping_dirty_helpers.c
+++ b/mm/mapping_dirty_helpers.c
@@ -3,6 +3,7 @@
 #include <linux/hugetlb.h>
 #include <linux/bitops.h>
 #include <linux/mmu_notifier.h>
+#include <linux/mm_inline.h>
 #include <asm/cacheflush.h>
 #include <asm/tlbflush.h>
 
@@ -23,7 +24,8 @@ struct wp_walk {
 /**
  * wp_pte - Write-protect a pte
  * @pte: Pointer to the pte
- * @addr: The virtual page address
+ * @addr: The start of protecting virtual address
+ * @end: The end of protecting virtual address
  * @walk: pagetable walk callback argument
  *
  * The function write-protects a pte and records the range in
@@ -33,7 +35,7 @@ static int wp_pte(pte_t *pte, unsigned long addr, unsigned long end,
 		  struct mm_walk *walk)
 {
 	struct wp_walk *wpwalk = walk->private;
-	pte_t ptent = *pte;
+	pte_t ptent = ptep_get(pte);
 
 	if (pte_write(ptent)) {
 		pte_t old_pte = ptep_modify_prot_start(walk->vma, addr, pte);
@@ -74,7 +76,8 @@ struct clean_walk {
  * clean_record_pte - Clean a pte and record its address space offset in a
  * bitmap
  * @pte: Pointer to the pte
- * @addr: The virtual page address
+ * @addr: The start of virtual address to be clean
+ * @end: The end of virtual address to be clean
  * @walk: pagetable walk callback argument
  *
  * The function cleans a pte and records the range in
@@ -88,7 +91,7 @@ static int clean_record_pte(pte_t *pte, unsigned long addr,
 {
 	struct wp_walk *wpwalk = walk->private;
 	struct clean_walk *cwalk = to_clean_walk(wpwalk);
-	pte_t ptent = *pte;
+	pte_t ptent = ptep_get(pte);
 
 	if (pte_dirty(ptent)) {
 		pgoff_t pgoff = ((addr - walk->vma->vm_start) >> PAGE_SHIFT) +
@@ -123,21 +126,13 @@ static int clean_record_pte(pte_t *pte, unsigned long addr,
 static int wp_clean_pmd_entry(pmd_t *pmd, unsigned long addr, unsigned long end,
 			      struct mm_walk *walk)
 {
-	pmd_t pmdval = pmd_read_atomic(pmd);
+	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;
 }
 
@@ -153,21 +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;
-	}
-
-	/* 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;
 }
 
@@ -186,7 +175,7 @@ static int wp_clean_pre_vma(unsigned long start, unsigned long end,
 	wpwalk->tlbflush_end = start;
 
 	mmu_notifier_range_init(&wpwalk->range, MMU_NOTIFY_PROTECTION_PAGE, 0,
-				walk->vma, walk->mm, start, end);
+				walk->mm, start, end);
 	mmu_notifier_invalidate_range_start(&wpwalk->range);
 	flush_cache_range(walk->vma, start, end);
 
@@ -299,13 +288,14 @@ EXPORT_SYMBOL_GPL(wp_shared_mapping_range);
  * @end: Pointer to the number of the last set bit in @bitmap.
  * none set. The value is modified as new bits are set by the function.
  *
- * Note: When this function returns there is no guarantee that a CPU has
+ * When this function returns there is no guarantee that a CPU has
  * not already dirtied new ptes. However it will not clean any ptes not
  * reported in the bitmap. The guarantees are as follows:
- * a) All ptes dirty when the function starts executing will end up recorded
- *    in the bitmap.
- * b) All ptes dirtied after that will either remain dirty, be recorded in the
- *    bitmap or both.
+ *
+ * * All ptes dirty when the function starts executing will end up recorded
+ *   in the bitmap.
+ * * All ptes dirtied after that will either remain dirty, be recorded in the
+ *   bitmap or both.
  *
  * If a caller needs to make sure all dirty ptes are picked up and none
  * additional are added, it first needs to write-protect the address-space
@@ -313,7 +303,7 @@ EXPORT_SYMBOL_GPL(wp_shared_mapping_range);
  * pfn_mkwrite(). And then after a TLB flush following the write-protection
  * pick up all dirty bits.
  *
- * Note: This function currently skips transhuge page-table entries, since
+ * This function currently skips transhuge page-table entries, since
  * it's intended for dirty-tracking on the PTE level. It will warn on
  * encountering transhuge dirty entries, though, and can easily be extended
  * to handle them as well.