rust: auxiliary: add registration_data_with() for ForLt types

Add registration_data_with() taking a for<'a> closure that receives
Pin<&'a F::Of<'a>>, which works with any ForLt type. Taking a for<'a>
closure rather than returning a direct reference prevents callers from
choosing a concrete lifetime for the data, which is required for
soundness with non-covariant ForLt types.

Extract the common null-check, TypeId-check and KBox-borrow logic into a
private registration_data_pinned() helper shared by both
registration_data_with() and the existing registration_data().

Relax Registration's bound from CovariantForLt to ForLt so that
non-covariant types can be registered.

Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Link: https://patch.msgid.link/20260626183630.2585057-4-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

0 files changed, 0 insertions, 0 deletions