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From: Andreas Hindborg <a.hindborg@kernel.org>
To: "Benno Lossin" <benno.lossin@proton.me>
Cc: "Miguel Ojeda" <ojeda@kernel.org>,  "Alex Gaynor"
 <alex.gaynor@gmail.com>,  "Boqun Feng" <boqun.feng@gmail.com>,  "Gary Guo"
 <gary@garyguo.net>,  =?utf-8?Q?Bj=C3=B6rn?= Roy Baron
 <bjorn3_gh@protonmail.com>,  "Alice
 Ryhl" <aliceryhl@google.com>,  "Trevor Gross" <tmgross@umich.edu>,
  <stable@vger.kernel.org>,  <rust-for-linux@vger.kernel.org>,
  <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] rust: init: fix `Zeroable` implementation for
 `Option<NonNull<T>>` and `Option<KBox<T>>`
In-Reply-To: <20250305132836.2145476-1-benno.lossin@proton.me> (Benno Lossin's
	message of "Wed, 05 Mar 2025 13:29:01 +0000")
References: <t9wrOFEcf8XZ-aKch1r7feu9gBB6Wqs6_KgnLoSF6eZ01wvr4zV4Rbl4McWKaM25TlwevH55D6Yy_gLi2idFLA==@protonmail.internalid>
	<20250305132836.2145476-1-benno.lossin@proton.me>
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Date: Wed, 05 Mar 2025 19:52:08 +0100
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"Benno Lossin" <benno.lossin@proton.me> writes:

> According to [1], `NonNull<T>` and `#[repr(transparent)]` wrapper types
> such as our custom `KBox<T>` have the null pointer optimization only if
> `T: Sized`. Thus remove the `Zeroable` implementation for the unsized
> case.
>
> Link: https://doc.rust-lang.org/stable/std/option/index.html#representation [1]
> Cc: stable@vger.kernel.org # v6.12+ (a custom patch will be needed for 6.6.y)
> Fixes: 38cde0bd7b67 ("rust: init: add `Zeroable` trait and `init::zeroed` function")
> Signed-off-by: Benno Lossin <benno.lossin@proton.me>
> ---

Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>


Best regards,
Andreas Hindborg