Re: [PATCH v2 1/4] rust: sync: reword the `Arc` safety comment for `Send`

[Benno Lossin]

On 5/23/23 16:44, Alice Ryhl wrote:
> The safety comment on `impl Send for Arc` talks about "directly"
> accessing the value, when it really means "accessing the value with a
> mutable reference". This commit clarifies that.
> 
> Suggested-by: Boqun Feng <boqun.feng@xxxxxxxxx>
> Signed-off-by: Alice Ryhl <aliceryhl@xxxxxxxxxx>
> Reviewed-by: Andreas Hindborg <a.hindborg@xxxxxxxxxxx>
> Reviewed-by: Boqun Feng <boqun.feng@xxxxxxxxx>

Reviewed-by: Benno Lossin <benno.lossin@xxxxxxxxx>

> ---
>   rust/kernel/sync/arc.rs | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs
> index e6d206242465..87a4c9ed712b 100644
> --- a/rust/kernel/sync/arc.rs
> +++ b/rust/kernel/sync/arc.rs
> @@ -146,8 +146,8 @@ impl<T: ?Sized + Unsize<U>, U: ?Sized> core::ops::DispatchFromDyn<Arc<U>> for Ar
> 
>   // SAFETY: It is safe to send `Arc<T>` to another thread when the underlying `T` is `Sync` because
>   // it effectively means sharing `&T` (which is safe because `T` is `Sync`); additionally, it needs
> -// `T` to be `Send` because any thread that has an `Arc<T>` may ultimately access `T` directly, for
> -// example, when the reference count reaches zero and `T` is dropped.
> +// `T` to be `Send` because any thread that has an `Arc<T>` may ultimately access `T` using a
> +// mutable reference, for example, when the reference count reaches zero and `T` is dropped.
>   unsafe impl<T: ?Sized + Sync + Send> Send for Arc<T> {}
> 
>   // SAFETY: It is safe to send `&Arc<T>` to another thread when the underlying `T` is `Sync` for the
> --
> 2.40.1.698.g37aff9b760-goog
> 

-- 
Cheers,
Benno