pipe: add pipe_buf_confirm() helper

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index d82414a..e5d5cc9 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -728,7 +728,7 @@
 		struct pipe_buffer *buf = cs->pipebufs;
 
 		if (!cs->write) {
-			err = buf->ops->confirm(cs->pipe, buf);
+			err = pipe_buf_confirm(cs->pipe, buf);
 			if (err)
 				return err;
 
@@ -828,7 +828,7 @@
 
 	fuse_copy_finish(cs);
 
-	err = buf->ops->confirm(cs->pipe, buf);
+	err = pipe_buf_confirm(cs->pipe, buf);
 	if (err)
 		return err;