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From: Alice Ryhl <aliceryhl@google.com>
To: Sagar Taunk <sagartaunk2@gmail.com>
Cc: "Miguel Ojeda" <ojeda@kernel.org>,
	"Boqun Feng" <boqun@kernel.org>, "Gary Guo" <gary@garyguo.net>,
	"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
	"Benno Lossin" <lossin@kernel.org>,
	"Andreas Hindborg" <a.hindborg@kernel.org>,
	"Trevor Gross" <tmgross@umich.edu>,
	"Danilo Krummrich" <dakr@kernel.org>,
	"Tamir Duberstein" <tamird@kernel.org>,
	"Daniel Almeida" <daniel.almeida@collabora.com>,
	"Viresh Kumar" <viresh.kumar@linaro.org>,
	rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] rust: workqueue: replace SAFETY TODO for `WorkItemPointer` impl on `Pin<KBox<T>>`
Date: Thu, 30 Apr 2026 08:41:41 +0000	[thread overview]
Message-ID: <afMVxV9iVgfllkkE@google.com> (raw)
In-Reply-To: <20260430071930.73696-1-sagartaunk2@gmail.com>

On Thu, Apr 30, 2026 at 12:49:28PM +0530, Sagar Taunk wrote:
> The original implementation left a `SAFETY: TODO` comment on the
> `WorkItemPointer` implementation for `Pin<KBox<T>>`. This patch documents
> the safety requirements that make this implementation sound.
> 
> The safety argument follows the same structure as the `Arc<T>`
> implementation and relies on three guarantees:
>  `__enqueue` strips the `Pin` wrapper via `Pin::into_inner_unchecked`
> and leaks the box via `KBox::into_raw`, producing `*mut T` whose
> allocation remains live for the duration of the queued work;
> `work_container_of` safely reverses the `raw_get_work` offset arithmetic to
> recover the exact `*mut T` that `__enqueue` produced; and the workqueue
> guarantees `run` is called exactly once, making `KBox::from_raw` sound.
> 
> Signed-off-by: Sagar Taunk <sagartaunk2@gmail.com>

Thanks

Reviewed-by: Alice Ryhl <aliceryhl@google.com>

      reply	other threads:[~2026-04-30  8:41 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-04-30  7:19 [PATCH v2] rust: workqueue: replace SAFETY TODO for `WorkItemPointer` impl on `Pin<KBox<T>>` Sagar Taunk
2026-04-30  8:41 ` Alice Ryhl [this message]

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