Re: [PATCH v5 3/5] rust: sync: Add abstraction for rcu_barrier()

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] The function name `rcu_barrier` causes module-level stuttering (`rcu::rcu_barrier()`).
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commit 7b2bfcaf9137cfae11ac6cf2b69d559a4e731460
Author: Philipp Stanner <phasta@kernel.org>

rust: sync: Add abstraction for rcu_barrier()

This commit adds a safe Rust abstraction for the C function rcu_barrier(),
which waits for all in-flight call_rcu() callbacks to complete.

> diff --git a/rust/kernel/sync/rcu.rs b/rust/kernel/sync/rcu.rs
> index a32bef6e490b0..7031ca5d24738 100644
> --- a/rust/kernel/sync/rcu.rs
> +++ b/rust/kernel/sync/rcu.rs
[ ... ]
> @@ -50,3 +50,23 @@ fn drop(&mut self) {
>  pub fn read_lock() -> Guard {
>      Guard::new()
>  }
> +
> +/// Wait until all in-flight call_rcu() callbacks complete.
> +///
> +/// Note that this primitive does not necessarily wait for an RCU grace period
> +/// to complete.  For example, if there are no RCU callbacks queued anywhere
> +/// in the system, then rcu_barrier() is within its rights to return
> +/// immediately, without waiting for anything, much less an RCU grace period.
> +/// In fact, rcu_barrier() will normally not result in any RCU grace periods
> +/// beyond those that were already destined to be executed.
> +///
> +/// In kernels built with CONFIG_RCU_LAZY=y, this function also hurries all
> +/// pending lazy RCU callbacks.
> +///
> +/// Note that this is one of the RCU primitives which must not be called in
> +/// atomic context.
> +#[inline]
> +pub fn rcu_barrier() {

[Severity: Low]
This isn't a bug, but naming this function rcu_barrier() inside the rcu
module leads to stuttering when called (i.e., rcu::rcu_barrier()). Would it
be better to name this simply barrier() so it can be called as
rcu::barrier(), similar to how rcu_read_lock() is exposed as
rcu::read_lock()?

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

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Sashiko AI review · https://sashiko.dev/#/patchset/20260703073141.3962604-2-phasta@kernel.org?part=3