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From:   Asahi Lina <lina@asahilina.net>
Date:   Fri, 14 Jul 2023 18:13:53 +0900
Subject: [PATCH RFC 01/11] rust: types: Add Opaque::zeroed()
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To:     Miguel Ojeda <ojeda@kernel.org>,
        Alex Gaynor <alex.gaynor@gmail.com>,
        Wedson Almeida Filho <wedsonaf@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>,
        Benno Lossin <benno.lossin@proton.me>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Nicolas Schier <nicolas@fjasle.eu>, Tom Rix <trix@redhat.com>,
        Daniel Vetter <daniel@ffwll.ch>
Cc:     Hector Martin <marcan@marcan.st>, Sven Peter <sven@svenpeter.dev>,
        Alyssa Rosenzweig <alyssa@rosenzweig.io>,
        asahi@lists.linux.dev, rust-for-linux@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org,
        llvm@lists.linux.dev, Asahi Lina <lina@asahilina.net>
Precedence: bulk

Opaque types are internally MaybeUninit, so it's safe to actually
zero-initialize them as long as we don't claim they are initialized.
This is useful for many FFI types that are expected to be zero-inited by
the user.

Signed-off-by: Asahi Lina <lina@asahilina.net>
---
 rust/kernel/types.rs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs
index 1e5380b16ed5..185d3493857e 100644
--- a/rust/kernel/types.rs
+++ b/rust/kernel/types.rs
@@ -237,6 +237,11 @@ pub const fn uninit() -> Self {
         Self(MaybeUninit::uninit())
     }
 
+    /// Creates a zeroed value.
+    pub fn zeroed() -> Self {
+        Self(MaybeUninit::zeroed())
+    }
+
     /// Creates a pin-initializer from the given initializer closure.
     ///
     /// The returned initializer calls the given closure with the pointer to the inner `T` of this

-- 
2.40.1