[readdir] constify ->actor

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/parisc/hpux/fs.c

@@ -111,19 +111,17 @@ int hpux_getdents(unsigned int fd, struct hpux_dirent __user *dirent, unsigned i
 {
 	struct fd arg;
 	struct hpux_dirent __user * lastdirent;
-	struct getdents_callback buf;
+	struct getdents_callback buf = {
+		.ctx.actor = filldir,
+		.current_dir = dirent,
+		.count = count
+	};
 	int error;
 
 	arg = fdget(fd);
 	if (!arg.file)
 		return -EBADF;
 
-	buf.current_dir = dirent;
-	buf.previous = NULL;
-	buf.count = count;
-	buf.error = 0;
-	buf.ctx.actor = filldir;
-
 	error = iterate_dir(arg.file, &buf.ctx);
 	if (error >= 0)
 		error = buf.error;