[RFC PATCH v1 05/10] mm: add filemap_dirty_folio_pages() helper

[Joanne Koong <joannelkoong@gmail.com>]

Add filemap_dirty_folio_pages() which takes in the number of pages to dirty.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
---
 fs/buffer.c               |  4 ++--
 include/linux/pagemap.h   |  2 +-
 include/linux/writeback.h |  2 ++
 mm/page-writeback.c       | 25 +++++++++++++++++++++----
 4 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index 327bae3f724d..7c05f6205d39 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -752,7 +752,7 @@ bool block_dirty_folio(struct address_space *mapping, struct folio *folio)
 
 	if (newly_dirty)
 		__folio_mark_dirty(folio, mapping, 1,
-				   folio_nr_pages(folio));
+				   folio_nr_pages(folio), true);
 
 	if (newly_dirty)
 		__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
@@ -1211,7 +1211,7 @@ void mark_buffer_dirty(struct buffer_head *bh)
 			mapping = folio->mapping;
 			if (mapping)
 				__folio_mark_dirty(folio, mapping, 0,
-						   folio_nr_pages(folio));
+						   folio_nr_pages(folio), true);
 		}
 		if (mapping)
 			__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 0ae2c1e93ca5..64f17aec9141 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -1205,7 +1205,7 @@ void folio_end_writeback(struct folio *folio);
 void folio_end_writeback_pages(struct folio *folio, long nr_pages);
 void folio_wait_stable(struct folio *folio);
 void __folio_mark_dirty(struct folio *folio, struct address_space *, int warn,
-		long nr_pages);
+		long nr_pages, bool newly_dirty);
 void folio_account_cleaned(struct folio *folio, struct bdi_writeback *wb);
 void __folio_cancel_dirty(struct folio *folio);
 static inline void folio_cancel_dirty(struct folio *folio)
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index eda4b62511f7..34afa6912a1c 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -383,6 +383,8 @@ void tag_pages_for_writeback(struct address_space *mapping,
 			     pgoff_t start, pgoff_t end);
 
 bool filemap_dirty_folio(struct address_space *mapping, struct folio *folio);
+bool filemap_dirty_folio_pages(struct address_space *mapping,
+			       struct folio *folio, long nr_pages);
 bool folio_redirty_for_writepage(struct writeback_control *, struct folio *);
 bool redirty_page_for_writepage(struct writeback_control *, struct page *);
 
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index b0ae10a6687d..a3805988f3ad 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2732,7 +2732,7 @@ void folio_account_cleaned(struct folio *folio, struct bdi_writeback *wb)
  * try_to_free_buffers() to fail.
  */
 void __folio_mark_dirty(struct folio *folio, struct address_space *mapping,
-			     int warn, long nr_pages)
+			     int warn, long nr_pages, bool newly_dirty)
 {
 	unsigned long flags;
 
@@ -2740,12 +2740,29 @@ void __folio_mark_dirty(struct folio *folio, struct address_space *mapping,
 	if (folio->mapping) {	/* Race with truncate? */
 		WARN_ON_ONCE(warn && !folio_test_uptodate(folio));
 		folio_account_dirtied(folio, mapping, nr_pages);
-		__xa_set_mark(&mapping->i_pages, folio_index(folio),
-				PAGECACHE_TAG_DIRTY);
+		if (newly_dirty)
+			__xa_set_mark(&mapping->i_pages, folio_index(folio),
+					PAGECACHE_TAG_DIRTY);
 	}
 	xa_unlock_irqrestore(&mapping->i_pages, flags);
 }
 
+bool filemap_dirty_folio_pages(struct address_space *mapping, struct folio *folio,
+			long nr_pages)
+{
+	bool newly_dirty = !folio_test_set_dirty(folio);
+
+	__folio_mark_dirty(folio, mapping, !folio_test_private(folio),
+			nr_pages, newly_dirty);
+
+	if (newly_dirty && mapping->host) {
+		/* !PageAnon && !swapper_space */
+		__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
+	}
+
+	return newly_dirty;
+}
+
 /**
  * filemap_dirty_folio - Mark a folio dirty for filesystems which do not use buffer_heads.
  * @mapping: Address space this folio belongs to.
@@ -2771,7 +2788,7 @@ bool filemap_dirty_folio(struct address_space *mapping, struct folio *folio)
 		return false;
 
 	__folio_mark_dirty(folio, mapping, !folio_test_private(folio),
-			folio_nr_pages(folio));
+			folio_nr_pages(folio), true);
 
 	if (mapping->host) {
 		/* !PageAnon && !swapper_space */
-- 
2.47.3