Re: [PATCH v3 07/16] rust: add `Revocable` type

[Alice Ryhl]

On Tue, Dec 3, 2024 at 10:21 AM Danilo Krummrich <dakr@xxxxxxxxxx> wrote:
>
> On 10/29/24 2:26 PM, Alice Ryhl wrote:
> > On Tue, Oct 22, 2024 at 11:33 PM Danilo Krummrich <dakr@xxxxxxxxxx> wrote:
> >> +/// A guard that allows access to a revocable object and keeps it alive.
> >> +///
> >> +/// CPUs may not sleep while holding on to [`RevocableGuard`] because it's in atomic context
> >> +/// holding the RCU read-side lock.
> >> +///
> >> +/// # Invariants
> >> +///
> >> +/// The RCU read-side lock is held while the guard is alive.
> >> +pub struct RevocableGuard<'a, T> {
> >> +    data_ref: *const T,
> >> +    _rcu_guard: rcu::Guard,
> >> +    _p: PhantomData<&'a ()>,
> >> +}
> >
> > Is this needed? Can't all users just use `try_access_with_guard`?
>
> Without this guard, how to we access `T` with just the `rcu::Guard`?

I don't think `try_access_with_guard` provides any access that you
can't get by doing `try_access_with_guard`.

That said, I guess this guard functions as a convenience accessors, so
I don't mind it.

Alice