Re: [PATCH v2 01/13] rust: sync: introduce `LockClassKey`

Greg KH
2023-04-05T18:00:23Z

On Wed, Apr 05, 2023 at 02:50:59PM -0300, Wedson Almeida Filho wrote:
> From: Wedson Almeida Filho <walmeida@microsoft.com>
>
> It is a wrapper around C's `lock_class_key`, which is used by the
> synchronisation primitives that are checked with lockdep. This is in
> preparation for introducing Rust abstractions for these primitives.
>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Waiman Long <longman@redhat.com>
> Co-developed-by: Boqun Feng <boqun.feng@gmail.com>
> Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
> Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
> ---
> v1 -> v2: Fixed a typo in comment
>
> rust/kernel/sync.rs | 45 +++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 45 insertions(+)
>
> diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs
> index 33da23e3076d..84a4b560828c 100644
> --- a/rust/kernel/sync.rs
> +++ b/rust/kernel/sync.rs
> @@ -5,6 +5,51 @@
> //! This module contains the kernel APIs related to synchronisation that have been ported or
> //! wrapped for usage by Rust code in the kernel.
>
> +use crate::types::Opaque;
> +
> mod arc;
>
> pub use arc::{Arc, ArcBorrow, UniqueArc};
> +
> +/// Represents a lockdep class. It's a wrapper around C's `lock_class_key`.
> +#[repr(transparent)]
> +pub struct LockClassKey(Opaque<bindings::lock_class_key>);

Will this disappear into "nothing" if lockdep is disabled in the build?

If not, it should, if so, I couldn't see where that option was, sorry
for the noise.

thanks,

greg k-h