[PATCH v12 31/33] mm/filemap: Add folio private_2 functions

[Matthew Wilcox (Oracle)]

end_page_private_2() becomes folio_end_private_2(),
wait_on_page_private_2() becomes folio_wait_private_2() and
wait_on_page_private_2_killable() becomes folio_wait_private_2_killable().

Adjust the fscache equivalents to call page_folio() before calling these
functions to avoid adding wrappers.  Ends up costing 1 byte of text
in ceph & netfs, but the core shrinks by three calls to page_folio().

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Reviewed-by: William Kucharski <william.kucharski@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: David Howells <dhowells@xxxxxxxxxx>
---
 include/linux/netfs.h   |  6 +++---
 include/linux/pagemap.h |  6 +++---
 mm/filemap.c            | 37 ++++++++++++++++---------------------
 3 files changed, 22 insertions(+), 27 deletions(-)

diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index 9062adfa2fb9..fad8c6209edd 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -55,7 +55,7 @@ static inline void set_page_fscache(struct page *page)
  */
 static inline void end_page_fscache(struct page *page)
 {
-	end_page_private_2(page);
+	folio_end_private_2(page_folio(page));
 }
 
 /**
@@ -66,7 +66,7 @@ static inline void end_page_fscache(struct page *page)
  */
 static inline void wait_on_page_fscache(struct page *page)
 {
-	wait_on_page_private_2(page);
+	folio_wait_private_2(page_folio(page));
 }
 
 /**
@@ -82,7 +82,7 @@ static inline void wait_on_page_fscache(struct page *page)
  */
 static inline int wait_on_page_fscache_killable(struct page *page)
 {
-	return wait_on_page_private_2_killable(page);
+	return folio_wait_private_2_killable(page_folio(page));
 }
 
 enum netfs_read_source {
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 1330d8d0ca26..6a06224afa2f 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -795,9 +795,9 @@ static inline void set_page_private_2(struct page *page)
 	SetPagePrivate2(page);
 }
 
-void end_page_private_2(struct page *page);
-void wait_on_page_private_2(struct page *page);
-int wait_on_page_private_2_killable(struct page *page);
+void folio_end_private_2(struct folio *folio);
+void folio_wait_private_2(struct folio *folio);
+int folio_wait_private_2_killable(struct folio *folio);
 
 /*
  * Add an arbitrary waiter to a page's wait queue
diff --git a/mm/filemap.c b/mm/filemap.c
index 7d8125f6c955..7b0e4d0e4741 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1451,56 +1451,51 @@ void folio_unlock(struct folio *folio)
 EXPORT_SYMBOL(folio_unlock);
 
 /**
- * end_page_private_2 - Clear PG_private_2 and release any waiters
- * @page: The page
+ * folio_end_private_2 - Clear PG_private_2 and wake any waiters.
+ * @folio: The folio.
  *
- * Clear the PG_private_2 bit on a page and wake up any sleepers waiting for
- * this.  The page ref held for PG_private_2 being set is released.
+ * Clear the PG_private_2 bit on a folio and wake up any sleepers waiting for
+ * it.  The page ref held for PG_private_2 being set is released.
  *
  * This is, for example, used when a netfs page is being written to a local
  * disk cache, thereby allowing writes to the cache for the same page to be
  * serialised.
  */
-void end_page_private_2(struct page *page)
+void folio_end_private_2(struct folio *folio)
 {
-	struct folio *folio = page_folio(page);
-
 	VM_BUG_ON_FOLIO(!folio_private_2(folio), folio);
 	clear_bit_unlock(PG_private_2, folio_flags(folio, 0));
 	folio_wake_bit(folio, PG_private_2);
 	folio_put(folio);
 }
-EXPORT_SYMBOL(end_page_private_2);
+EXPORT_SYMBOL(folio_end_private_2);
 
 /**
- * wait_on_page_private_2 - Wait for PG_private_2 to be cleared on a page
- * @page: The page to wait on
+ * folio_wait_private_2 - Wait for PG_private_2 to be cleared on a page.
+ * @folio: The folio to wait on.
  *
- * Wait for PG_private_2 (aka PG_fscache) to be cleared on a page.
+ * Wait for PG_private_2 (aka PG_fscache) to be cleared on a folio.
  */
-void wait_on_page_private_2(struct page *page)
+void folio_wait_private_2(struct folio *folio)
 {
-	struct folio *folio = page_folio(page);
-
 	while (folio_private_2(folio))
 		folio_wait_bit(folio, PG_private_2);
 }
-EXPORT_SYMBOL(wait_on_page_private_2);
+EXPORT_SYMBOL(folio_wait_private_2);
 
 /**
- * wait_on_page_private_2_killable - Wait for PG_private_2 to be cleared on a page
- * @page: The page to wait on
+ * folio_wait_private_2_killable - Wait for PG_private_2 to be cleared on a folio.
+ * @folio: The folio to wait on.
  *
- * Wait for PG_private_2 (aka PG_fscache) to be cleared on a page or until a
+ * Wait for PG_private_2 (aka PG_fscache) to be cleared on a folio or until a
  * fatal signal is received by the calling task.
  *
  * Return:
  * - 0 if successful.
  * - -EINTR if a fatal signal was encountered.
  */
-int wait_on_page_private_2_killable(struct page *page)
+int folio_wait_private_2_killable(struct folio *folio)
 {
-	struct folio *folio = page_folio(page);
 	int ret = 0;
 
 	while (folio_private_2(folio)) {
@@ -1511,7 +1506,7 @@ int wait_on_page_private_2_killable(struct page *page)
 
 	return ret;
 }
-EXPORT_SYMBOL(wait_on_page_private_2_killable);
+EXPORT_SYMBOL(folio_wait_private_2_killable);
 
 /**
  * folio_end_writeback - End writeback against a folio.
-- 
2.30.2