mm/rmap: Add folio_mkclean()

Transform page_mkclean() into folio_mkclean() and add a page_mkclean()
wrapper around folio_mkclean().

folio_mkclean is 15 bytes smaller than page_mkclean, but the kernel
is enlarged by 33 bytes due to inlining page_folio() into each caller.
This will go away once the callers are converted to use folio_mkclean().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>

include/linux/rmap.h

@@ -235,7 +235,7 @@ unsigned long page_address_in_vma(struct page *, struct vm_area_struct *);
  *
  * returns the number of cleaned PTEs.
  */
-int page_mkclean(struct page *);
+int folio_mkclean(struct folio *);
 
 /*
  * called in munlock()/munmap() path to check for other vmas holding
@@ -295,12 +295,14 @@ static inline void try_to_unmap(struct page *page, enum ttu_flags flags)
 {
 }
 
-static inline int page_mkclean(struct page *page)
+static inline int folio_mkclean(struct folio *folio)
 {
 	return 0;
 }
-
-
 #endif	/* CONFIG_MMU */
 
+static inline int page_mkclean(struct page *page)
+{
+	return folio_mkclean(page_folio(page));
+}
 #endif	/* _LINUX_RMAP_H */

mm/rmap.c

@@ -981,7 +981,7 @@ static bool invalid_mkclean_vma(struct vm_area_struct *vma, void *arg)
 	return true;
 }
 
-int page_mkclean(struct page *page)
+int folio_mkclean(struct folio *folio)
 {
 	int cleaned = 0;
 	struct address_space *mapping;
@@ -991,20 +991,20 @@ int page_mkclean(struct page *page)
 		.invalid_vma = invalid_mkclean_vma,
 	};
 
-	BUG_ON(!PageLocked(page));
+	BUG_ON(!folio_test_locked(folio));
 
-	if (!page_mapped(page))
+	if (!folio_mapped(folio))
 		return 0;
 
-	mapping = page_mapping(page);
+	mapping = folio_mapping(folio);
 	if (!mapping)
 		return 0;
 
-	rmap_walk(page, &rwc);
+	rmap_walk(&folio->page, &rwc);
 
 	return cleaned;
 }
-EXPORT_SYMBOL_GPL(page_mkclean);
+EXPORT_SYMBOL_GPL(folio_mkclean);
 
 /**
  * page_move_anon_rmap - move a page to our anon_vma