[PATCH v3 17/25] mm/filemap: Convert end_page_writeback to end_folio_writeback

[Matthew Wilcox (Oracle)]

Add a wrapper function for users that are not yet converted to folios.
With a distro config, this function shrinks from 213 bytes to 105 bytes
due to elimination of repeated calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <wi...@infradead.org>
---
 include/linux/pagemap.h |  6 +++++-
 mm/filemap.c            | 30 +++++++++++++++---------------
 2 files changed, 20 insertions(+), 16 deletions(-)

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 131d1aa2af61..67d3badc9fe0 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -758,7 +758,11 @@ static inline void wait_on_page_fscache(struct page *page)
 
 int put_and_wait_on_page_locked(struct page *page, int state);
 void wait_on_page_writeback(struct page *page);
-extern void end_page_writeback(struct page *page);
+void end_folio_writeback(struct folio *folio);
+static inline void end_page_writeback(struct page *page)
+{
+       return end_folio_writeback(page_folio(page));
+}
 void wait_for_stable_page(struct page *page);
 
 void page_endio(struct page *page, bool is_write, int err);
diff --git a/mm/filemap.c b/mm/filemap.c
index a54eb4641385..65008c42e47d 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1147,11 +1147,11 @@ static void wake_up_page_bit(struct page *page, int 
bit_nr)
        spin_unlock_irqrestore(&q->lock, flags);
 }
 
-static void wake_up_page(struct page *page, int bit)
+static void wake_up_folio(struct folio *folio, int bit)
 {
-       if (!PageWaiters(page))
+       if (!FolioWaiters(folio))
                return;
-       wake_up_page_bit(page, bit);
+       wake_up_page_bit(&folio->page, bit);
 }
 
 /*
@@ -1443,10 +1443,10 @@ void unlock_page_fscache(struct page *page)
 EXPORT_SYMBOL(unlock_page_fscache);
 
 /**
- * end_page_writeback - end writeback against a page
- * @page: the page
+ * end_folio_writeback - End writeback against a page.
+ * @folio: The page.
  */
-void end_page_writeback(struct page *page)
+void end_folio_writeback(struct folio *folio)
 {
        /*
         * TestClearPageReclaim could be used here but it is an atomic
@@ -1455,26 +1455,26 @@ void end_page_writeback(struct page *page)
         * justify taking an atomic operation penalty at the end of
         * ever page writeback.
         */
-       if (PageReclaim(page)) {
-               ClearPageReclaim(page);
-               rotate_reclaimable_page(page);
+       if (FolioReclaim(folio)) {
+               ClearFolioReclaim(folio);
+               rotate_reclaimable_page(&folio->page);
        }
 
        /*
         * Writeback does not hold a page reference of its own, relying
         * on truncation to wait for the clearing of PG_writeback.
         * But here we must make sure that the page is not freed and
-        * reused before the wake_up_page().
+        * reused before the wake_up_folio().
         */
-       get_page(page);
-       if (!test_clear_page_writeback(page))
+       get_folio(folio);
+       if (!test_clear_page_writeback(&folio->page))
                BUG();
 
        smp_mb__after_atomic();
-       wake_up_page(page, PG_writeback);
-       put_page(page);
+       wake_up_folio(folio, PG_writeback);
+       put_folio(folio);
 }
-EXPORT_SYMBOL(end_page_writeback);
+EXPORT_SYMBOL(end_folio_writeback);
 
 /*
  * After completing I/O on a page, call this routine to update the page
-- 
2.29.2