Re: [PATCH v2 1/2] random: move add_hwgenerator_randomness()'s wait outside function

[Sven van Ashbrook]

On Mon, Sep 19, 2022 at 11:06 AM Jason A. Donenfeld <Jason@xxxxxxxxx> wrote:
>
> By the way, there was a recent ath9k patch that kind of went to a
> similar tune. [...] Maybe that's a potential solution here, or
> something similar to it.

Jason was kind enough to point me to the patch in question:
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=36cb6494429bd64b27b7ff8b4af56f8e526da2b4

This patch limits the long sleep inside the fillfn kthread, by
terminating the sleep on
hwrng_unregister().

This doesn't appear like a viable approach for the suspend/resume issue?
- there is a great multitude of tpm_msleep()/msleep() calls in the tpm's
  rng_get_data() path. They would all have to be made interruptible.
- even if interrupted successfully, now the kthread must be blocked until
  after resume. If so, what is the point of using a non-freezable kthread.