jffs2: Convert jffs2 to read_folio

This is a "weak" conversion which converts straight back to using pages.
A full conversion should be performed at some point, hopefully by
someone familiar with the filesystem.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

fs/jffs2/file.c

@@ -27,7 +27,7 @@ static int jffs2_write_end(struct file *filp, struct address_space *mapping,
 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
 			loff_t pos, unsigned len,
 			struct page **pagep, void **fsdata);
-static int jffs2_readpage (struct file *filp, struct page *pg);
+static int jffs2_read_folio(struct file *filp, struct folio *folio);
 
 int jffs2_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 {
@@ -72,7 +72,7 @@ const struct inode_operations jffs2_file_inode_operations =
 
 const struct address_space_operations jffs2_file_address_operations =
 {
-	.readpage =	jffs2_readpage,
+	.read_folio =	jffs2_read_folio,
 	.write_begin =	jffs2_write_begin,
 	.write_end =	jffs2_write_end,
 };
@@ -118,13 +118,13 @@ int jffs2_do_readpage_unlock(void *data, struct page *pg)
 }
 
 
-static int jffs2_readpage (struct file *filp, struct page *pg)
+static int jffs2_read_folio(struct file *file, struct folio *folio)
 {
-	struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host);
+	struct jffs2_inode_info *f = JFFS2_INODE_INFO(folio->mapping->host);
 	int ret;
 
 	mutex_lock(&f->sem);
-	ret = jffs2_do_readpage_unlock(pg->mapping->host, pg);
+	ret = jffs2_do_readpage_unlock(folio->mapping->host, &folio->page);
 	mutex_unlock(&f->sem);
 	return ret;
 }

fs/jffs2/fs.c

@@ -178,7 +178,7 @@ int jffs2_do_setattr (struct inode *inode, struct iattr *iattr)
 	jffs2_complete_reservation(c);
 
 	/* We have to do the truncate_setsize() without f->sem held, since
-	   some pages may be locked and waiting for it in readpage().
+	   some pages may be locked and waiting for it in read_folio().
 	   We are protected from a simultaneous write() extending i_size
 	   back past iattr->ia_size, because do_truncate() holds the
 	   generic inode semaphore. */