[PATCH v2 1/4] mm: convert FPB_IGNORE_* into FPB_RESPECT_*

[David Hildenbrand <david@redhat.com>]

Respecting these PTE bits is the exception, so let's invert the meaning.

With this change, most callers don't have to pass any flags. This is
a preparation for splitting folio_pte_batch() into a non-inlined
variant that doesn't consume any flags.

Long-term, we want folio_pte_batch() to probably ignore most common
PTE bits (e.g., write/dirty/young/soft-dirty) that are not relevant for
most page table walkers: uffd-wp and protnone might be bits to consider in
the future. Only walkers that care about them can opt-in to respect them.

No functional change intended.

Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 mm/internal.h  | 16 ++++++++--------
 mm/madvise.c   |  3 +--
 mm/memory.c    | 11 +++++------
 mm/mempolicy.c |  4 +---
 mm/mlock.c     |  3 +--
 mm/mremap.c    |  3 +--
 mm/rmap.c      |  3 +--
 7 files changed, 18 insertions(+), 25 deletions(-)

diff --git a/mm/internal.h b/mm/internal.h
index e84217e27778d..170d55b6851ff 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -202,17 +202,17 @@ static inline void vma_close(struct vm_area_struct *vma)
 /* Flags for folio_pte_batch(). */
 typedef int __bitwise fpb_t;
 
-/* Compare PTEs after pte_mkclean(), ignoring the dirty bit. */
-#define FPB_IGNORE_DIRTY		((__force fpb_t)BIT(0))
+/* Compare PTEs respecting the dirty bit. */
+#define FPB_RESPECT_DIRTY		((__force fpb_t)BIT(0))
 
-/* Compare PTEs after pte_clear_soft_dirty(), ignoring the soft-dirty bit. */
-#define FPB_IGNORE_SOFT_DIRTY		((__force fpb_t)BIT(1))
+/* Compare PTEs respecting the soft-dirty bit. */
+#define FPB_RESPECT_SOFT_DIRTY		((__force fpb_t)BIT(1))
 
 static inline pte_t __pte_batch_clear_ignored(pte_t pte, fpb_t flags)
 {
-	if (flags & FPB_IGNORE_DIRTY)
+	if (!(flags & FPB_RESPECT_DIRTY))
 		pte = pte_mkclean(pte);
-	if (likely(flags & FPB_IGNORE_SOFT_DIRTY))
+	if (likely(!(flags & FPB_RESPECT_SOFT_DIRTY)))
 		pte = pte_clear_soft_dirty(pte);
 	return pte_wrprotect(pte_mkold(pte));
 }
@@ -236,8 +236,8 @@ static inline pte_t __pte_batch_clear_ignored(pte_t pte, fpb_t flags)
  * pages of the same large folio.
  *
  * All PTEs inside a PTE batch have the same PTE bits set, excluding the PFN,
- * the accessed bit, writable bit, dirty bit (with FPB_IGNORE_DIRTY) and
- * soft-dirty bit (with FPB_IGNORE_SOFT_DIRTY).
+ * the accessed bit, writable bit, dirty bit (unless FPB_RESPECT_DIRTY is set)
+ * and soft-dirty bit (unless FPB_RESPECT_SOFT_DIRTY is set).
  *
  * start_ptep must map any page of the folio. max_nr must be at least one and
  * must be limited by the caller so scanning cannot exceed a single page table.
diff --git a/mm/madvise.c b/mm/madvise.c
index e61e32b2cd91f..661bb743d2216 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -347,10 +347,9 @@ static inline int madvise_folio_pte_batch(unsigned long addr, unsigned long end,
 					  pte_t pte, bool *any_young,
 					  bool *any_dirty)
 {
-	const fpb_t fpb_flags = FPB_IGNORE_DIRTY | FPB_IGNORE_SOFT_DIRTY;
 	int max_nr = (end - addr) / PAGE_SIZE;
 
-	return folio_pte_batch(folio, addr, ptep, pte, max_nr, fpb_flags, NULL,
+	return folio_pte_batch(folio, addr, ptep, pte, max_nr, 0, NULL,
 			       any_young, any_dirty);
 }
 
diff --git a/mm/memory.c b/mm/memory.c
index 0f9b32a20e5b7..0a47583ca9937 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -990,10 +990,10 @@ copy_present_ptes(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma
 	 * by keeping the batching logic separate.
 	 */
 	if (unlikely(!*prealloc && folio_test_large(folio) && max_nr != 1)) {
-		if (src_vma->vm_flags & VM_SHARED)
-			flags |= FPB_IGNORE_DIRTY;
-		if (!vma_soft_dirty_enabled(src_vma))
-			flags |= FPB_IGNORE_SOFT_DIRTY;
+		if (!(src_vma->vm_flags & VM_SHARED))
+			flags |= FPB_RESPECT_DIRTY;
+		if (vma_soft_dirty_enabled(src_vma))
+			flags |= FPB_RESPECT_SOFT_DIRTY;
 
 		nr = folio_pte_batch(folio, addr, src_pte, pte, max_nr, flags,
 				     &any_writable, NULL, NULL);
@@ -1535,7 +1535,6 @@ static inline int zap_present_ptes(struct mmu_gather *tlb,
 		struct zap_details *details, int *rss, bool *force_flush,
 		bool *force_break, bool *any_skipped)
 {
-	const fpb_t fpb_flags = FPB_IGNORE_DIRTY | FPB_IGNORE_SOFT_DIRTY;
 	struct mm_struct *mm = tlb->mm;
 	struct folio *folio;
 	struct page *page;
@@ -1565,7 +1564,7 @@ static inline int zap_present_ptes(struct mmu_gather *tlb,
 	 * by keeping the batching logic separate.
 	 */
 	if (unlikely(folio_test_large(folio) && max_nr != 1)) {
-		nr = folio_pte_batch(folio, addr, pte, ptent, max_nr, fpb_flags,
+		nr = folio_pte_batch(folio, addr, pte, ptent, max_nr, 0,
 				     NULL, NULL, NULL);
 
 		zap_present_folio_ptes(tlb, vma, folio, page, pte, ptent, nr,
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 1ff7b2174eb77..2a25eedc3b1c0 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -675,7 +675,6 @@ static void queue_folios_pmd(pmd_t *pmd, struct mm_walk *walk)
 static int queue_folios_pte_range(pmd_t *pmd, unsigned long addr,
 			unsigned long end, struct mm_walk *walk)
 {
-	const fpb_t fpb_flags = FPB_IGNORE_DIRTY | FPB_IGNORE_SOFT_DIRTY;
 	struct vm_area_struct *vma = walk->vma;
 	struct folio *folio;
 	struct queue_pages *qp = walk->private;
@@ -713,8 +712,7 @@ static int queue_folios_pte_range(pmd_t *pmd, unsigned long addr,
 			continue;
 		if (folio_test_large(folio) && max_nr != 1)
 			nr = folio_pte_batch(folio, addr, pte, ptent,
-					     max_nr, fpb_flags,
-					     NULL, NULL, NULL);
+					     max_nr, 0, NULL, NULL, NULL);
 		/*
 		 * vm_normal_folio() filters out zero pages, but there might
 		 * still be reserved folios to skip, perhaps in a VDSO.
diff --git a/mm/mlock.c b/mm/mlock.c
index 3cb72b579ffd3..2238cdc5eb1c1 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -307,14 +307,13 @@ void munlock_folio(struct folio *folio)
 static inline unsigned int folio_mlock_step(struct folio *folio,
 		pte_t *pte, unsigned long addr, unsigned long end)
 {
-	const fpb_t fpb_flags = FPB_IGNORE_DIRTY | FPB_IGNORE_SOFT_DIRTY;
 	unsigned int count = (end - addr) >> PAGE_SHIFT;
 	pte_t ptent = ptep_get(pte);
 
 	if (!folio_test_large(folio))
 		return 1;
 
-	return folio_pte_batch(folio, addr, pte, ptent, count, fpb_flags, NULL,
+	return folio_pte_batch(folio, addr, pte, ptent, count, 0, NULL,
 			       NULL, NULL);
 }
 
diff --git a/mm/mremap.c b/mm/mremap.c
index 36585041c760d..d4d3ffc931502 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -173,7 +173,6 @@ static pte_t move_soft_dirty_pte(pte_t pte)
 static int mremap_folio_pte_batch(struct vm_area_struct *vma, unsigned long addr,
 		pte_t *ptep, pte_t pte, int max_nr)
 {
-	const fpb_t flags = FPB_IGNORE_DIRTY | FPB_IGNORE_SOFT_DIRTY;
 	struct folio *folio;
 
 	if (max_nr == 1)
@@ -183,7 +182,7 @@ static int mremap_folio_pte_batch(struct vm_area_struct *vma, unsigned long addr
 	if (!folio || !folio_test_large(folio))
 		return 1;
 
-	return folio_pte_batch(folio, addr, ptep, pte, max_nr, flags, NULL,
+	return folio_pte_batch(folio, addr, ptep, pte, max_nr, 0, NULL,
 			       NULL, NULL);
 }
 
diff --git a/mm/rmap.c b/mm/rmap.c
index 34311f654d0c2..98ed3e49e8bbe 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1849,7 +1849,6 @@ static inline unsigned int folio_unmap_pte_batch(struct folio *folio,
 			struct page_vma_mapped_walk *pvmw,
 			enum ttu_flags flags, pte_t pte)
 {
-	const fpb_t fpb_flags = FPB_IGNORE_DIRTY | FPB_IGNORE_SOFT_DIRTY;
 	unsigned long end_addr, addr = pvmw->address;
 	struct vm_area_struct *vma = pvmw->vma;
 	unsigned int max_nr;
@@ -1869,7 +1868,7 @@ static inline unsigned int folio_unmap_pte_batch(struct folio *folio,
 	if (pte_unused(pte))
 		return 1;
 
-	return folio_pte_batch(folio, addr, pvmw->pte, pte, max_nr, fpb_flags,
+	return folio_pte_batch(folio, addr, pvmw->pte, pte, max_nr, 0,
 			       NULL, NULL, NULL);
 }
 
-- 
2.49.0