Re: [PATCH v2 3/6] rust: sync: Add abstraction for synchronize_rcu()

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [Low] Missing `#[inline]` annotation on the `synchronize_rcu()` abstraction.
- [Low] Existing uses of `bindings::synchronize_rcu()` were not updated to use the new safe abstraction.
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commit 3f3ebd383ebd5385e032e8ee41ba8e2dc2c9f4e9
Author: Philipp Stanner <phasta@kernel.org>

rust: sync: Add abstraction for synchronize_rcu()

This commit adds a safe Rust abstraction for the synchronize_rcu() function
to wait for a grace period.

> diff --git a/rust/kernel/sync/rcu.rs b/rust/kernel/sync/rcu.rs
> index eef34bf862596..d86d615467b1e 100644
> --- a/rust/kernel/sync/rcu.rs
> +++ b/rust/kernel/sync/rcu.rs
[ ... ]
> @@ -56,3 +56,11 @@ pub fn rcu_barrier() {
>      // SAFETY: `rcu_barrier()` is always safe to be called. It just might wait for a grace period.
>      unsafe { bindings::rcu_barrier() };
>  }
> +
> +/// Wait for one RCU grace period.
> +///
> +/// You typically do this to wait for everyone holding a [`Guard`].
> +pub fn synchronize_rcu() {

[Severity: Low]
This isn't a bug, but should this function have an #[inline] annotation?

According to the Rust subsystem guidelines, functions in abstractions that
are small or simply forward to a binding call should be annotated with
#[inline].

Additionally, should the existing usages of the raw C binding be updated
to use this new safe abstraction?

For example, drop() in rust/kernel/sync/poll.rs currently does:

    unsafe { bindings::synchronize_rcu() };

And revoke_internal() in rust/kernel/revocable.rs:

    unsafe { bindings::synchronize_rcu() };

Updating these existing callers would help reduce unnecessary unsafe blocks
across the codebase now that a safe wrapper is available.

> +    // SAFETY: `synchronize_rcu()` is always safe to be called. It just waits for a grace period.
> +    unsafe { bindings::synchronize_rcu() };
> +}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260616082819.2943886-2-phasta@kernel.org?part=3