[PATCH RFC 12/14] treewide: replace PagePrivate() with page_private()

PG_private is going to be removed and its check is replaced by checking
page->private != NULL.

Replace page_buffers() with page_private() and delete page_buffers(),
since only two users left and both can be converted to use page_private().

Assisted-by: Claude:claude-opus-4-8
Assisted-by: Codex:gpt-5
Signed-off-by: Zi Yan <[email protected]>
To: Song Liu <[email protected]>
To: Yu Kuai <[email protected]>
To: Ilya Dryomov <[email protected]>
To: Alex Markuze <[email protected]>
To: Viacheslav Dubeyko <[email protected]>
Cc: Li Nan <[email protected]>
Cc: Xiao Ni <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
---
 drivers/md/md-bitmap.c      | 6 +++---
 fs/ceph/addr.c              | 4 +---
 include/linux/buffer_head.h | 6 ------
 3 files changed, 4 insertions(+), 12 deletions(-)

diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index 0f02e2956398d..affd4807013e1 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -516,7 +516,7 @@ static void end_bitmap_write(struct bio *bio)
 
 static void write_file_page(struct bitmap *bitmap, struct page *page, int wait)
 {
-	struct buffer_head *bh = page_buffers(page);
+	struct buffer_head *bh = (struct buffer_head *)page_private(page);
 
 	while (bh && bh->b_blocknr) {
 		atomic_inc(&bitmap->pending_writes);
@@ -535,10 +535,10 @@ static void free_buffers(struct page *page)
 {
 	struct buffer_head *bh;
 
-	if (!PagePrivate(page))
+	if (!page_private(page))
 		return;
 
-	bh = page_buffers(page);
+	bh = (struct buffer_head *)page_private(page);
 	while (bh) {
 		struct buffer_head *next = bh->b_this_page;
 		free_buffer_head(bh);
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index ecf33b66610c8..92074db8732ac 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -70,9 +70,7 @@ static int ceph_netfs_check_write_begin(struct file *file, loff_t pos, unsigned
 
 static inline struct ceph_snap_context *page_snap_context(struct page *page)
 {
-	if (PagePrivate(page))
-		return (void *)page->private;
-	return NULL;
+	return (void *)page->private;
 }
 
 /*
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index 8b23bc9a244cb..5cf0b8c058ce0 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -175,12 +175,6 @@ static inline unsigned long bh_offset(const struct buffer_head *bh)
 	return (unsigned long)(bh)->b_data & (page_size(bh->b_page) - 1);
 }
 
-/* If we *know* page->private refers to buffer_heads */
-#define page_buffers(page)					\
-	({							\
-		BUG_ON(!PagePrivate(page));			\
-		((struct buffer_head *)page_private(page));	\
-	})
 #define folio_buffers(folio)		folio_get_private(folio)
 
 void buffer_check_dirty_writeback(struct folio *folio,

-- 
2.53.0