mm/writeback: Add folio_cancel_dirty()

Turn __cancel_dirty_page() into __folio_cancel_dirty() and add wrappers.
Move the prototypes into pagemap.h since this is page cache functionality.
Saves 44 bytes of kernel text in total; 33 bytes from __folio_cancel_dirty
and 11 from two callers of cancel_dirty_page().

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>

1 files changed, 11 insertions, 0 deletions

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 8ba7da513ac4..8f4a9ba0bfb0 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -785,6 +785,17 @@ static inline void account_page_cleaned(struct page *page,
 {
 	return folio_account_cleaned(page_folio(page), mapping, wb);
 }
+void __folio_cancel_dirty(struct folio *folio);
+static inline void folio_cancel_dirty(struct folio *folio)
+{
+	/* Avoid atomic ops, locking, etc. when not actually needed. */
+	if (folio_test_dirty(folio))
+		__folio_cancel_dirty(folio);
+}
+static inline void cancel_dirty_page(struct page *page)
+{
+	folio_cancel_dirty(page_folio(page));
+}
 
 int __set_page_dirty_nobuffers(struct page *page);
 int __set_page_dirty_no_writeback(struct page *page);