Re: [PATCH v3 00/13] rust: drm: Higher-Ranked Lifetime private data

[Danilo Krummrich]

On Sat Jun 20, 2026 at 2:51 AM CEST, Danilo Krummrich wrote:
>   rust: drm: Add RegistrationGuard for drm_dev_enter/exit critical
>     sections

As also pointed out by Sashiko, I forgot to consider that constructing a
RegistrationGuard still requires that the drm::Device has been registered at
some point.

Theoretically, this could be addressed in a way that it is still valid to
construct a RegistrationGuard from a drm::Device<Normal> (e.g. by leveraging
dev->unplugged with corresponding synchronization), but other than from IOCTLs
there is no use-case for this guard. Since IOCTLs already carry the required
invariant implicitly, I went with a separate Ioctl typestate.

This and the fact that we can't let drivers infer any other typestate than
Normal before the RegistrationGuard is in place, results in a few changes that
are worth considering for review, so I decided to resend early.