mm: Turn page_anon_vma() into folio_anon_vma()

Move the prototype from mm.h to mm/internal.h and convert all callers
to pass a folio.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Author: Matthew Wilcox (Oracle)

include/linux/mm.h

@@ -1730,7 +1730,6 @@ static inline void *folio_address(const struct folio *folio)
 }
 
 extern void *page_rmapping(struct page *page);
-extern struct anon_vma *page_anon_vma(struct page *page);
 extern pgoff_t __page_file_index(struct page *page);
 
 /*

mm/internal.h

@@ -392,6 +392,7 @@ static inline bool is_data_mapping(vm_flags_t flags)
 void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
 		struct vm_area_struct *prev);
 void __vma_unlink_list(struct mm_struct *mm, struct vm_area_struct *vma);
+struct anon_vma *folio_anon_vma(struct folio *folio);
 
 #ifdef CONFIG_MMU
 void unmap_mapping_folio(struct folio *folio);

mm/ksm.c

@@ -2554,7 +2554,8 @@ void __ksm_exit(struct mm_struct *mm)
 struct page *ksm_might_need_to_copy(struct page *page,
 			struct vm_area_struct *vma, unsigned long address)
 {
-	struct anon_vma *anon_vma = page_anon_vma(page);
+	struct folio *folio = page_folio(page);
+	struct anon_vma *anon_vma = folio_anon_vma(folio);
 	struct page *new_page;
 
 	if (PageKsm(page)) {

mm/rmap.c

@@ -737,8 +737,9 @@ static bool should_defer_flush(struct mm_struct *mm, enum ttu_flags flags)
  */
 unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
 {
-	if (PageAnon(page)) {
-		struct anon_vma *page__anon_vma = page_anon_vma(page);
+	struct folio *folio = page_folio(page);
+	if (folio_test_anon(folio)) {
+		struct anon_vma *page__anon_vma = folio_anon_vma(folio);
 		/*
 		 * Note: swapoff's unuse_vma() is more efficient with this
 		 * check, and needs it to match anon_vma when KSM is active.
@@ -748,7 +749,7 @@ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
 			return -EFAULT;
 	} else if (!vma->vm_file) {
 		return -EFAULT;
-	} else if (vma->vm_file->f_mapping != compound_head(page)->mapping) {
+	} else if (vma->vm_file->f_mapping != folio->mapping) {
 		return -EFAULT;
 	}
 
@@ -1103,6 +1104,7 @@ static void __page_set_anon_rmap(struct page *page,
 static void __page_check_anon_rmap(struct page *page,
 	struct vm_area_struct *vma, unsigned long address)
 {
+	struct folio *folio = page_folio(page);
 	/*
 	 * The page's anon-rmap details (mapping and index) are guaranteed to
 	 * be set up correctly at this point.
@@ -1114,7 +1116,8 @@ static void __page_check_anon_rmap(struct page *page,
 	 * are initially only visible via the pagetables, and the pte is locked
 	 * over the call to page_add_new_anon_rmap.
 	 */
-	VM_BUG_ON_PAGE(page_anon_vma(page)->root != vma->anon_vma->root, page);
+	VM_BUG_ON_FOLIO(folio_anon_vma(folio)->root != vma->anon_vma->root,
+			folio);
 	VM_BUG_ON_PAGE(page_to_pgoff(page) != linear_page_index(vma, address),
 		       page);
 }
@@ -2177,6 +2180,7 @@ void __put_anon_vma(struct anon_vma *anon_vma)
 static struct anon_vma *rmap_walk_anon_lock(struct page *page,
 					struct rmap_walk_control *rwc)
 {
+	struct folio *folio = page_folio(page);
 	struct anon_vma *anon_vma;
 
 	if (rwc->anon_lock)
@@ -2188,7 +2192,7 @@ static struct anon_vma *rmap_walk_anon_lock(struct page *page,
 	 * are holding mmap_lock. Users without mmap_lock are required to
 	 * take a reference count to prevent the anon_vma disappearing
 	 */
-	anon_vma = page_anon_vma(page);
+	anon_vma = folio_anon_vma(folio);
 	if (!anon_vma)
 		return NULL;
 
@@ -2208,14 +2212,15 @@ static struct anon_vma *rmap_walk_anon_lock(struct page *page,
 static void rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc,
 		bool locked)
 {
+	struct folio *folio = page_folio(page);
 	struct anon_vma *anon_vma;
 	pgoff_t pgoff_start, pgoff_end;
 	struct anon_vma_chain *avc;
 
 	if (locked) {
-		anon_vma = page_anon_vma(page);
+		anon_vma = folio_anon_vma(folio);
 		/* anon_vma disappear under us? */
-		VM_BUG_ON_PAGE(!anon_vma, page);
+		VM_BUG_ON_FOLIO(!anon_vma, folio);
 	} else {
 		anon_vma = rmap_walk_anon_lock(page, rwc);
 	}

mm/util.c

@@ -679,9 +679,8 @@ bool folio_mapped(struct folio *folio)
 }
 EXPORT_SYMBOL(folio_mapped);
 
-struct anon_vma *page_anon_vma(struct page *page)
+struct anon_vma *folio_anon_vma(struct folio *folio)
 {
-	struct folio *folio = page_folio(page);
 	unsigned long mapping = (unsigned long)folio->mapping;
 
 	if ((mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON)