From: Julia Lawall <redacted>
Date: Mon, 12 Sep 2016 11:07:15 +0200 (CEST)

So foo is protected, but its lifetime of interest is quite short.  But we
can't set the ops field of the type of xxx to be const either, because it
is obviously not - the code above modifies it.

You can definitely make it a pointer to a const thing.

Just like "netdev_ops" in struct net_device is const.