From: Ondrej Mosnáček on
gitlab.com
https://gitlab.com/cki-project/kernel-ark/-/merge_requests/1304#note_6482...
I like how you used `filp->private_data` to stash the module pointer, but you
could also put there the whole rng pointer and use it here, avoiding the need
to use `rcu_dereference_raw()`. (Sorry for another nitpick, but I think it'll
be easier to understand the code that way.)