mm/fs: convert inode_attach_wb() to take a folio

Patch series "Writeback folio conversions".

Remove more calls to compound_head() by passing folios around instead of
pages.


This patch (of 2):

The only caller of inode_attach_wb() which doesn't pass NULL already has a
folio, so convert the whole call-chain to take folios.

Link: https://lkml.kernel.org/r/20230116192507.2146150-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20230116192507.2146150-2-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/fs-writeback.c

@@ -237,7 +237,7 @@ void wb_wait_for_completion(struct wb_completion *done)
 static atomic_t isw_nr_in_flight = ATOMIC_INIT(0);
 static struct workqueue_struct *isw_wq;
 
-void __inode_attach_wb(struct inode *inode, struct page *page)
+void __inode_attach_wb(struct inode *inode, struct folio *folio)
 {
 	struct backing_dev_info *bdi = inode_to_bdi(inode);
 	struct bdi_writeback *wb = NULL;
@@ -245,8 +245,8 @@ void __inode_attach_wb(struct inode *inode, struct page *page)
 	if (inode_cgwb_enabled(inode)) {
 		struct cgroup_subsys_state *memcg_css;
 
-		if (page) {
-			memcg_css = mem_cgroup_css_from_page(page);
+		if (folio) {
+			memcg_css = mem_cgroup_css_from_page(&folio->page);
 			wb = wb_get_create(bdi, memcg_css, GFP_ATOMIC);
 		} else {
 			/* must pin memcg_css, see wb_get_create() */

include/linux/writeback.h

@@ -207,7 +207,7 @@ static inline void wait_on_inode(struct inode *inode)
 #include <linux/cgroup.h>
 #include <linux/bio.h>
 
-void __inode_attach_wb(struct inode *inode, struct page *page);
+void __inode_attach_wb(struct inode *inode, struct folio *folio);
 void wbc_attach_and_unlock_inode(struct writeback_control *wbc,
 				 struct inode *inode)
 	__releases(&inode->i_lock);
@@ -222,16 +222,16 @@ bool cleanup_offline_cgwb(struct bdi_writeback *wb);
 /**
  * inode_attach_wb - associate an inode with its wb
  * @inode: inode of interest
- * @page: page being dirtied (may be NULL)
+ * @folio: folio being dirtied (may be NULL)
  *
  * If @inode doesn't have its wb, associate it with the wb matching the
- * memcg of @page or, if @page is NULL, %current.  May be called w/ or w/o
+ * memcg of @folio or, if @folio is NULL, %current.  May be called w/ or w/o
  * @inode->i_lock.
  */
-static inline void inode_attach_wb(struct inode *inode, struct page *page)
+static inline void inode_attach_wb(struct inode *inode, struct folio *folio)
 {
 	if (!inode->i_wb)
-		__inode_attach_wb(inode, page);
+		__inode_attach_wb(inode, folio);
 }
 
 /**
@@ -290,7 +290,7 @@ static inline void wbc_init_bio(struct writeback_control *wbc, struct bio *bio)
 
 #else	/* CONFIG_CGROUP_WRITEBACK */
 
-static inline void inode_attach_wb(struct inode *inode, struct page *page)
+static inline void inode_attach_wb(struct inode *inode, struct folio *folio)
 {
 }
 

mm/page-writeback.c

@@ -2652,7 +2652,7 @@ static void folio_account_dirtied(struct folio *folio,
 		struct bdi_writeback *wb;
 		long nr = folio_nr_pages(folio);
 
-		inode_attach_wb(inode, &folio->page);
+		inode_attach_wb(inode, folio);
 		wb = inode_to_wb(inode);
 
 		__lruvec_stat_mod_folio(folio, NR_FILE_DIRTY, nr);