[PATCH 08/22] mm: Add folio_add_new_anon_rmap()

["Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>]

In contrast to other rmap functions, page_add_new_anon_rmap() is always
called with a freshly allocated page.  That means it can't be called with
a tail page.  Turn page_add_new_anon_rmap() into folio_add_new_anon_rmap()
and add a page_add_new_anon_rmap() wrapper.  Callers can be converted
individually.

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
 include/linux/rmap.h |  2 ++
 mm/folio-compat.c    |  8 ++++++++
 mm/rmap.c            | 23 +++++++++++------------
 3 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index bd3504d11b15..aa682a2a93ce 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -194,6 +194,8 @@ void page_add_anon_rmap(struct page *, struct vm_area_struct *,
 		unsigned long address, rmap_t flags);
 void page_add_new_anon_rmap(struct page *, struct vm_area_struct *,
 		unsigned long address);
+void folio_add_new_anon_rmap(struct folio *, struct vm_area_struct *,
+		unsigned long address);
 void page_add_file_rmap(struct page *, struct vm_area_struct *,
 		bool compound);
 void page_remove_rmap(struct page *, struct vm_area_struct *,
diff --git a/mm/folio-compat.c b/mm/folio-compat.c
index 69ed25790c68..92f53adc0dd9 100644
--- a/mm/folio-compat.c
+++ b/mm/folio-compat.c
@@ -123,3 +123,11 @@ void putback_lru_page(struct page *page)
 {
 	folio_putback_lru(page_folio(page));
 }
+
+void page_add_new_anon_rmap(struct page *page, struct vm_area_struct *vma,
+		unsigned long address)
+{
+	VM_BUG_ON_PAGE(PageTail(page), page);
+
+	return folio_add_new_anon_rmap((struct folio *)page, vma, address);
+}
diff --git a/mm/rmap.c b/mm/rmap.c
index 71fbe4a65b93..3297b88b5698 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1287,29 +1287,28 @@ void page_add_anon_rmap(struct page *page, struct vm_area_struct *vma,
  * This means the inc-and-test can be bypassed.
  * Page does not have to be locked.
  */
-void page_add_new_anon_rmap(struct page *page,
-	struct vm_area_struct *vma, unsigned long address)
+void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *vma,
+		unsigned long address)
 {
 	int nr;
 
 	VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma);
-	__SetPageSwapBacked(page);
+	__folio_set_swapbacked(folio);
 
-	if (likely(!PageCompound(page))) {
+	if (likely(!folio_test_large(folio))) {
 		/* increment count (starts at -1) */
-		atomic_set(&page->_mapcount, 0);
+		atomic_set(&folio->_mapcount, 0);
 		nr = 1;
 	} else {
-		VM_BUG_ON_PAGE(!PageTransHuge(page), page);
 		/* increment count (starts at -1) */
-		atomic_set(compound_mapcount_ptr(page), 0);
-		atomic_set(subpages_mapcount_ptr(page), COMPOUND_MAPPED);
-		nr = thp_nr_pages(page);
-		__mod_lruvec_page_state(page, NR_ANON_THPS, nr);
+		atomic_set(&folio->_entire_mapcount, 0);
+		atomic_set(&folio->_nr_pages_mapped, COMPOUND_MAPPED);
+		nr = folio_nr_pages(folio);
+		__lruvec_stat_mod_folio(folio, NR_ANON_THPS, nr);
 	}
 
-	__mod_lruvec_page_state(page, NR_ANON_MAPPED, nr);
-	__page_set_anon_rmap(page, vma, address, 1);
+	__lruvec_stat_mod_folio(folio, NR_ANON_MAPPED, nr);
+	__page_set_anon_rmap(&folio->page, vma, address, 1);
 }
 
 /**
-- 
2.35.1