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References: <20231012132131.300014-1-benno.lossin@proton.me>
In-Reply-To: <20231012132131.300014-1-benno.lossin@proton.me>
From:   Alice Ryhl <aliceryhl@google.com>
Date:   Thu, 12 Oct 2023 15:43:29 +0200
Message-ID: <CAH5fLgg=AmuR-93vuVmdr_oVUYCYuYas7Unrm0UFtQ2Yc3x6wA@mail.gmail.com>
Subject: Re: [PATCH] rust: macros: improve `#[vtable]` documentation
To:     Benno Lossin <benno.lossin@proton.me>
Cc:     Miguel Ojeda <ojeda@kernel.org>,
        Wedson Almeida Filho <wedsonaf@gmail.com>,
        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>,
        Andreas Hindborg <nmi@metaspace.dk>,
        rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org
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On Thu, Oct 12, 2023 at 3:22=E2=80=AFPM Benno Lossin <benno.lossin@proton.m=
e> wrote:
>
> Traits marked with `#[vtable]` need to provide default implementations
> for optional functions. The C side represents these with `NULL` in the
> vtable, so the default functions are never actually called. We do not
> want to replicate the default behavior from C in Rust, because that is
> not maintainable. Therefore we should use `build_error` in those default
> implementations. The error message for that is provided at
> `kernel::error::VTABLE_DEFAULT_ERROR`.
>
> Signed-off-by: Benno Lossin <benno.lossin@proton.me>

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