From aeef0f8a3af2e3003c1c4019cf8fcb5f4b14f17f Mon Sep 17 00:00:00 2001
From: Alice Ryhl <aliceryhl@google.com>
Date: Tue, 13 Oct 2026 12:37:54 +0000
Subject: [PATCH] rust: error: implement ZeroableOption for Error

Rust Binder wants to store an Option<Error> in TransactionInfo, which
derives Zeroable. Implement ZeroableOption for Error so that
Option<Error> implements Zeroable.

Acked-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20261013-binder-consolidate-txn-prints-v2-1-cf78927dab23@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 rust/kernel/error.rs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs
index e52793f77196..9003a1b86da8 100644
--- a/rust/kernel/error.rs
+++ b/rust/kernel/error.rs
@@ -199,8 +199,13 @@ macro_rules! declare_err {
 ///
 /// The value is a valid `errno` (i.e. `>= -MAX_ERRNO && < 0`).
 #[derive(Clone, Copy, PartialEq, Eq)]
+#[repr(transparent)]
 pub struct Error(NonZeroI32);
 
+// SAFETY: `Error` is `repr(transparent)` over `NonZeroI32`, which is part of the option layout
+// optimization guarantee, so all zeroes is a valid representation for `None`.
+unsafe impl pin_init::ZeroableOption for Error {}
+
 impl Error {
     /// Creates an [`Error`] from a kernel error code.
     ///