linux-kernel - [PATCH v2 14/15] rust: pin-init: internal: init: simplify Zeroable safety check

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Message-ID: <20260111122554.2662175-15-lossin@kernel.org>
Date: Sun, 11 Jan 2026 13:25:12 +0100
From: Benno Lossin <lossin@...nel.org>
To: Benno Lossin <lossin@...nel.org>,
	Gary Guo <gary@...yguo.net>,
	Miguel Ojeda <ojeda@...nel.org>,
	Boqun Feng <boqun.feng@...il.com>,
	Björn Roy Baron <bjorn3_gh@...tonmail.com>,
	Andreas Hindborg <a.hindborg@...nel.org>,
	Alice Ryhl <aliceryhl@...gle.com>,
	Trevor Gross <tmgross@...ch.edu>,
	Danilo Krummrich <dakr@...nel.org>
Cc: rust-for-linux@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2 14/15] rust: pin-init: internal: init: simplify Zeroable safety check

The `Zeroable` type check uses a small dance with a raw pointer to aid
type inference. It turns out that this is not necessary and type
inference is powerful enough to resolve any ambiguity. Thus remove it.

Suggested-by: Gary Guo <gary@...yguo.net>
Signed-off-by: Benno Lossin <lossin@...nel.org>
---
Changes in v2: added this patch
---
 rust/pin-init/internal/src/init.rs | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/rust/pin-init/internal/src/init.rs b/rust/pin-init/internal/src/init.rs
index 40df01635a3a..17ae7b2e4f70 100644
--- a/rust/pin-init/internal/src/init.rs
+++ b/rust/pin-init/internal/src/init.rs
@@ -415,17 +415,12 @@ fn make_field_check(
             #[allow(unreachable_code, clippy::diverging_sub_expression, unused_assignments)]
             // SAFETY: this code is never executed.
             let _ = || unsafe {
-                let mut zeroed = ::core::mem::zeroed();
-                // We have to use type inference here to make zeroed have the correct type. This
-                // does not get executed, so it has no effect.
-                ::core::ptr::write(slot, zeroed);
-                zeroed = ::core::mem::zeroed();
                 ::core::ptr::write(slot, #path {
                     #(
                         #(#field_attrs)*
                         #field_name: ::core::panic!(),
                     )*
-                    ..zeroed
+                    ..::core::mem::zeroed()
                 })
             };
         },
-- 
2.52.0