Re: [PATCH 2/2] rust: arc: remove `ArcBorrow` in favour of `WithRef`

[Gary Guo]

On Thu, 21 Sep 2023 18:34:40 -0300
Wedson Almeida Filho <wedsonaf@xxxxxxxxx> wrote:

> From: Wedson Almeida Filho <walmeida@xxxxxxxxxxxxx>
> 
> With GATs, we don't need a separate type to represent a borrowed object
> with a refcount, we can just use Rust's regular shared borrowing. In
> this case, we use `&WithRef<T>` instead of `ArcBorrow<'_, T>`.
> 
> Co-developed-by: Boqun Feng <boqun.feng@xxxxxxxxx>
> Signed-off-by: Boqun Feng <boqun.feng@xxxxxxxxx>
> Signed-off-by: Wedson Almeida Filho <walmeida@xxxxxxxxxxxxx>

Reviewed-by: Gary Guo <gary@xxxxxxxxxxx>

The implementation looks good to me, thanks Wedson.

A minor thing that worth considering is to implement `AlwaysRefCounted`
to `WithRef` and reimplement `Arc` with `ARef<TaskRef<T>>` or add
conversion functions between them.

It feels natural to have this this impl (because `WithRef` is indeed
always ref counted), but on the other hand I don't currently foresee
anyone to currently want to use this API :(

> ---
>  rust/kernel/sync.rs     |   2 +-
>  rust/kernel/sync/arc.rs | 180 ++++++++++++++--------------------------
>  2 files changed, 62 insertions(+), 120 deletions(-)