[PATCH v14 2/9] rust: rename `AlwaysRefCounted` to `RefCounted`.

[Gary Guo]

On Wed Feb 4, 2026 at 11:56 AM GMT, Andreas Hindborg wrote:
> From: Oliver Mangold <oliver.mangold at pm.me>
> 
> There are types where it may both be reference counted in some cases and
> owned in others. In such cases, obtaining `ARef<T>` from `&T` would be
> unsound as it allows creation of `ARef<T>` copy from `&Owned<T>`.
> 
> Therefore, we split `AlwaysRefCounted` into `RefCounted` (which `ARef<T>`
> would require) and a marker trait to indicate that the type is always
> reference counted (and not `Ownable`) so the `&T` -> `ARef<T>` conversion
> is possible.
> 
> - Rename `AlwaysRefCounted` to `RefCounted`.
> - Add a new unsafe trait `AlwaysRefCounted`.
> - Implement the new trait `AlwaysRefCounted` for the newly renamed
>   `RefCounted` implementations. This leaves functionality of existing
>   implementers of `AlwaysRefCounted` intact.
> 
> Original patch by Oliver Mangold <oliver.mangold at pm.me> [1].
> 
> Link: https://lore.kernel.org/r/20251117-unique-ref-v13-2-b5b243df1250@pm.me [1]
> Suggested-by: Alice Ryhl <aliceryhl at google.com>
> Reviewed-by: Daniel Almeida <daniel.almeida at collabora.com>
> Signed-off-by: Andreas Hindborg <a.hindborg at kernel.org>

I think you also need to update the `AlwaysRefCounted` reference mentioned in
the `Owned` patch too? (Or perhaps this patch should be moved before `Owned`
instead?)

With that fixed:

Reviewed-by: Gary Guo <gary at garyguo.net>

> ---
>  rust/kernel/auxiliary.rs        |  7 +++++-
>  rust/kernel/block/mq/request.rs | 15 +++++++------
>  rust/kernel/cred.rs             | 13 ++++++++++--
>  rust/kernel/device.rs           | 10 ++++++---
>  rust/kernel/device/property.rs  |  7 +++++-
>  rust/kernel/drm/device.rs       | 10 ++++++---
>  rust/kernel/drm/gem/mod.rs      |  8 ++++---
>  rust/kernel/fs/file.rs          | 16 ++++++++++----
>  rust/kernel/i2c.rs              | 16 +++++++++-----
>  rust/kernel/mm.rs               | 15 +++++++++----
>  rust/kernel/mm/mmput_async.rs   |  9 ++++++--
>  rust/kernel/opp.rs              | 10 ++++++---
>  rust/kernel/owned.rs            |  2 +-
>  rust/kernel/pci.rs              | 10 ++++++++-
>  rust/kernel/pid_namespace.rs    | 12 +++++++++--
>  rust/kernel/platform.rs         |  7 +++++-
>  rust/kernel/sync/aref.rs        | 47 ++++++++++++++++++++++++++---------------
>  rust/kernel/task.rs             | 10 ++++++---
>  rust/kernel/types.rs            |  3 ++-
>  19 files changed, 164 insertions(+), 63 deletions(-)