1 files changed, 80 insertions, 35 deletions

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index b7944a833668..683a04088f3f 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -171,7 +171,7 @@ static inline void anon_vma_merge(struct vm_area_struct *vma,
 	unlink_anon_vmas(next);
 }
 
-struct anon_vma *folio_get_anon_vma(struct folio *folio);
+struct anon_vma *folio_get_anon_vma(const struct folio *folio);
 
 /* RMAP flags, currently only relevant for some anon rmap operations. */
 typedef int __bitwise rmap_t;
@@ -194,12 +194,15 @@ enum rmap_level {
 	RMAP_LEVEL_PMD,
 };
 
-static inline void __folio_rmap_sanity_checks(struct folio *folio,
-		struct page *page, int nr_pages, enum rmap_level level)
+static inline void __folio_rmap_sanity_checks(const struct folio *folio,
+		const struct page *page, int nr_pages, enum rmap_level level)
 {
 	/* hugetlb folios are handled separately. */
 	VM_WARN_ON_FOLIO(folio_test_hugetlb(folio), folio);
 
+	/* When (un)mapping zeropages, we should never touch ref+mapcount. */
+	VM_WARN_ON_FOLIO(is_zero_folio(folio), folio);
+
 	/*
 	 * TODO: we get driver-allocated folios that have nothing to do with
 	 * the rmap using vm_insert_page(); therefore, we cannot assume that
@@ -241,7 +244,7 @@ void folio_add_anon_rmap_ptes(struct folio *, struct page *, int nr_pages,
 void folio_add_anon_rmap_pmd(struct folio *, struct page *,
 		struct vm_area_struct *, unsigned long address, rmap_t flags);
 void folio_add_new_anon_rmap(struct folio *, struct vm_area_struct *,
-		unsigned long address);
+		unsigned long address, rmap_t flags);
 void folio_add_file_rmap_ptes(struct folio *, struct page *, int nr_pages,
 		struct vm_area_struct *);
 #define folio_add_file_rmap_pte(folio, page, vma) \
@@ -273,6 +276,7 @@ static inline int hugetlb_try_dup_anon_rmap(struct folio *folio,
 		ClearPageAnonExclusive(&folio->page);
 	}
 	atomic_inc(&folio->_entire_mapcount);
+	atomic_inc(&folio->_large_mapcount);
 	return 0;
 }
 
@@ -284,7 +288,7 @@ static inline int hugetlb_try_share_anon_rmap(struct folio *folio)
 	VM_WARN_ON_FOLIO(!PageAnonExclusive(&folio->page), folio);
 
 	/* Paired with the memory barrier in try_grab_folio(). */
-	if (IS_ENABLED(CONFIG_HAVE_FAST_GUP))
+	if (IS_ENABLED(CONFIG_HAVE_GUP_FAST))
 		smp_mb();
 
 	if (unlikely(folio_maybe_dma_pinned(folio)))
@@ -295,7 +299,7 @@ static inline int hugetlb_try_share_anon_rmap(struct folio *folio)
 	 * This is conceptually a smp_wmb() paired with the smp_rmb() in
 	 * gup_must_unshare().
 	 */
-	if (IS_ENABLED(CONFIG_HAVE_FAST_GUP))
+	if (IS_ENABLED(CONFIG_HAVE_GUP_FAST))
 		smp_mb__after_atomic();
 	return 0;
 }
@@ -306,6 +310,7 @@ static inline void hugetlb_add_file_rmap(struct folio *folio)
 	VM_WARN_ON_FOLIO(folio_test_anon(folio), folio);
 
 	atomic_inc(&folio->_entire_mapcount);
+	atomic_inc(&folio->_large_mapcount);
 }
 
 static inline void hugetlb_remove_rmap(struct folio *folio)
@@ -313,21 +318,31 @@ static inline void hugetlb_remove_rmap(struct folio *folio)
 	VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio);
 
 	atomic_dec(&folio->_entire_mapcount);
+	atomic_dec(&folio->_large_mapcount);
 }
 
 static __always_inline void __folio_dup_file_rmap(struct folio *folio,
 		struct page *page, int nr_pages, enum rmap_level level)
 {
+	const int orig_nr_pages = nr_pages;
+
 	__folio_rmap_sanity_checks(folio, page, nr_pages, level);
 
 	switch (level) {
 	case RMAP_LEVEL_PTE:
+		if (!folio_test_large(folio)) {
+			atomic_inc(&folio->_mapcount);
+			break;
+		}
+
 		do {
 			atomic_inc(&page->_mapcount);
 		} while (page++, --nr_pages > 0);
+		atomic_add(orig_nr_pages, &folio->_large_mapcount);
 		break;
 	case RMAP_LEVEL_PMD:
 		atomic_inc(&folio->_entire_mapcount);
+		atomic_inc(&folio->_large_mapcount);
 		break;
 	}
 }
@@ -347,8 +362,12 @@ static inline void folio_dup_file_rmap_ptes(struct folio *folio,
 {
 	__folio_dup_file_rmap(folio, page, nr_pages, RMAP_LEVEL_PTE);
 }
-#define folio_dup_file_rmap_pte(folio, page) \
-	folio_dup_file_rmap_ptes(folio, page, 1)
+
+static __always_inline void folio_dup_file_rmap_pte(struct folio *folio,
+		struct page *page)
+{
+	__folio_dup_file_rmap(folio, page, 1, RMAP_LEVEL_PTE);
+}
 
 /**
  * folio_dup_file_rmap_pmd - duplicate a PMD mapping of a page range of a folio
@@ -373,6 +392,7 @@ static __always_inline int __folio_try_dup_anon_rmap(struct folio *folio,
 		struct page *page, int nr_pages, struct vm_area_struct *src_vma,
 		enum rmap_level level)
 {
+	const int orig_nr_pages = nr_pages;
 	bool maybe_pinned;
 	int i;
 
@@ -401,11 +421,20 @@ static __always_inline int __folio_try_dup_anon_rmap(struct folio *folio,
 				if (PageAnonExclusive(page + i))
 					return -EBUSY;
 		}
+
+		if (!folio_test_large(folio)) {
+			if (PageAnonExclusive(page))
+				ClearPageAnonExclusive(page);
+			atomic_inc(&folio->_mapcount);
+			break;
+		}
+
 		do {
 			if (PageAnonExclusive(page))
 				ClearPageAnonExclusive(page);
 			atomic_inc(&page->_mapcount);
 		} while (page++, --nr_pages > 0);
+		atomic_add(orig_nr_pages, &folio->_large_mapcount);
 		break;
 	case RMAP_LEVEL_PMD:
 		if (PageAnonExclusive(page)) {
@@ -414,6 +443,7 @@ static __always_inline int __folio_try_dup_anon_rmap(struct folio *folio,
 			ClearPageAnonExclusive(page);
 		}
 		atomic_inc(&folio->_entire_mapcount);
+		atomic_inc(&folio->_large_mapcount);
 		break;
 	}
 	return 0;
@@ -448,8 +478,13 @@ static inline int folio_try_dup_anon_rmap_ptes(struct folio *folio,
 	return __folio_try_dup_anon_rmap(folio, page, nr_pages, src_vma,
 					 RMAP_LEVEL_PTE);
 }
-#define folio_try_dup_anon_rmap_pte(folio, page, vma) \
-	folio_try_dup_anon_rmap_ptes(folio, page, 1, vma)
+
+static __always_inline int folio_try_dup_anon_rmap_pte(struct folio *folio,
+		struct page *page, struct vm_area_struct *src_vma)
+{
+	return __folio_try_dup_anon_rmap(folio, page, 1, src_vma,
+					 RMAP_LEVEL_PTE);
+}
 
 /**
  * folio_try_dup_anon_rmap_pmd - try duplicating a PMD mapping of a page range
@@ -541,7 +576,7 @@ static __always_inline int __folio_try_share_anon_rmap(struct folio *folio,
 	 */
 
 	/* Paired with the memory barrier in try_grab_folio(). */
-	if (IS_ENABLED(CONFIG_HAVE_FAST_GUP))
+	if (IS_ENABLED(CONFIG_HAVE_GUP_FAST))
 		smp_mb();
 
 	if (unlikely(folio_maybe_dma_pinned(folio)))
@@ -552,7 +587,7 @@ static __always_inline int __folio_try_share_anon_rmap(struct folio *folio,
 	 * This is conceptually a smp_wmb() paired with the smp_rmb() in
 	 * gup_must_unshare().
 	 */
-	if (IS_ENABLED(CONFIG_HAVE_FAST_GUP))
+	if (IS_ENABLED(CONFIG_HAVE_GUP_FAST))
 		smp_mb__after_atomic();
 	return 0;
 }
@@ -649,16 +684,6 @@ struct page_vma_mapped_walk {
 	unsigned int flags;
 };
 
-#define DEFINE_PAGE_VMA_WALK(name, _page, _vma, _address, _flags)	\
-	struct page_vma_mapped_walk name = {				\
-		.pfn = page_to_pfn(_page),				\
-		.nr_pages = compound_nr(_page),				\
-		.pgoff = page_to_pgoff(_page),				\
-		.vma = _vma,						\
-		.address = _address,					\
-		.flags = _flags,					\
-	}
-
 #define DEFINE_FOLIO_VMA_WALK(name, _folio, _vma, _address, _flags)	\
 	struct page_vma_mapped_walk name = {				\
 		.pfn = folio_pfn(_folio),				\
@@ -678,12 +703,33 @@ static inline void page_vma_mapped_walk_done(struct page_vma_mapped_walk *pvmw)
 		spin_unlock(pvmw->ptl);
 }
 
-bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw);
-
-/*
- * Used by swapoff to help locate where page is expected in vma.
+/**
+ * page_vma_mapped_walk_restart - Restart the page table walk.
+ * @pvmw: Pointer to struct page_vma_mapped_walk.
+ *
+ * It restarts the page table walk when changes occur in the page
+ * table, such as splitting a PMD. Ensures that the PTL held during
+ * the previous walk is released and resets the state to allow for
+ * a new walk starting at the current address stored in pvmw->address.
  */
-unsigned long page_address_in_vma(struct page *, struct vm_area_struct *);
+static inline void
+page_vma_mapped_walk_restart(struct page_vma_mapped_walk *pvmw)
+{
+	WARN_ON_ONCE(!pvmw->pmd && !pvmw->pte);
+
+	if (likely(pvmw->ptl))
+		spin_unlock(pvmw->ptl);
+	else
+		WARN_ON_ONCE(1);
+
+	pvmw->ptl = NULL;
+	pvmw->pmd = NULL;
+	pvmw->pte = NULL;
+}
+
+bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw);
+unsigned long page_address_in_vma(const struct folio *folio,
+		const struct page *, const struct vm_area_struct *);
 
 /*
  * Cleans the PTEs of shared mappings.
@@ -696,9 +742,12 @@ int folio_mkclean(struct folio *);
 int pfn_mkclean_range(unsigned long pfn, unsigned long nr_pages, pgoff_t pgoff,
 		      struct vm_area_struct *vma);
 
-void remove_migration_ptes(struct folio *src, struct folio *dst, bool locked);
+enum rmp_flags {
+	RMP_LOCKED		= 1 << 0,
+	RMP_USE_SHARED_ZEROPAGE	= 1 << 1,
+};
 
-int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma);
+void remove_migration_ptes(struct folio *src, struct folio *dst, int flags);
 
 /*
  * rmap_walk_control: To control rmap traversing for specific needs
@@ -722,14 +771,14 @@ struct rmap_walk_control {
 	bool (*rmap_one)(struct folio *folio, struct vm_area_struct *vma,
 					unsigned long addr, void *arg);
 	int (*done)(struct folio *folio);
-	struct anon_vma *(*anon_lock)(struct folio *folio,
+	struct anon_vma *(*anon_lock)(const struct folio *folio,
 				      struct rmap_walk_control *rwc);
 	bool (*invalid_vma)(struct vm_area_struct *vma, void *arg);
 };
 
 void rmap_walk(struct folio *folio, struct rmap_walk_control *rwc);
 void rmap_walk_locked(struct folio *folio, struct rmap_walk_control *rwc);
-struct anon_vma *folio_lock_anon_vma_read(struct folio *folio,
+struct anon_vma *folio_lock_anon_vma_read(const struct folio *folio,
 					  struct rmap_walk_control *rwc);
 
 #else	/* !CONFIG_MMU */
@@ -755,8 +804,4 @@ static inline int folio_mkclean(struct folio *folio)
 }
 #endif	/* CONFIG_MMU */
 
-static inline int page_mkclean(struct page *page)
-{
-	return folio_mkclean(page_folio(page));
-}
 #endif	/* _LINUX_RMAP_H */