Re: [PATCH v2] rust: doc: Clarify safety invariants for Revocable type

["Benno Lossin" <lossin@kernel.org>]

On Fri May 23, 2025 at 9:19 AM CEST, Danilo Krummrich wrote:
> On 5/19/25 2:26 PM, Benno Lossin wrote:
>> I'm not happy with the sentence structure, so how about:
>> 
>> * `data` is valid for reads in two cases:
>>      * while `is_available` is true, or
>>      * while the RCU read-side lock is taken and it was acquired while `is_available` was `true`.
>
> That sounds good!
>
>> * `data` is valid for writes when `is_available` was atomically changed from `true` to `false`.
>> 
>> The last one is needed in order to call `drop_in_place`.
>
> If think for this you have the same conditional, in the RCU case you can't call
> drop_in_place() immediately after is_available was altered, but have to wait for
> synchronize_rcu() to return.

Oh yeah, how about:

* `data` is valid for writes when `is_available` was atomically changed from `true to `false`
  and no thread is holding an RCU read-side lock that was acquired prior to the change in
  `is_available`.

---
Cheers,
Benno