relay_consume_bytes(rbuf, buf->private);
 }
 
-static struct pipe_buf_operations relay_pipe_buf_ops = {
+static const struct pipe_buf_operations relay_pipe_buf_ops = {
        .can_merge = 0,
        .map = generic_pipe_buf_map,
        .unmap = generic_pipe_buf_unmap,
 
        __free_page(spd->pages[idx]);
 }
 
-static struct pipe_buf_operations tracing_pipe_buf_ops = {
+static const struct pipe_buf_operations tracing_pipe_buf_ops = {
        .can_merge              = 0,
        .map                    = generic_pipe_buf_map,
        .unmap                  = generic_pipe_buf_unmap,
 }
 
 /* Pipe buffer operations for a buffer. */
-static struct pipe_buf_operations buffer_pipe_buf_ops = {
+static const struct pipe_buf_operations buffer_pipe_buf_ops = {
        .can_merge              = 0,
        .map                    = generic_pipe_buf_map,
        .unmap                  = generic_pipe_buf_unmap,
 
 
 
 /* Pipe buffer operations for a socket. */
-static struct pipe_buf_operations sock_pipe_buf_ops = {
+static const struct pipe_buf_operations sock_pipe_buf_ops = {
        .can_merge = 0,
        .map = generic_pipe_buf_map,
        .unmap = generic_pipe_buf_unmap,