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Date:   Mon, 23 Oct 2023 07:01:28 +0000
To:     Alice Ryhl <alice@ryhl.io>
From:   Benno Lossin <benno.lossin@proton.me>
Cc:     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>,
        Andreas Hindborg <nmi@metaspace.dk>,
        rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org,
        Miguel Ojeda <ojeda@kernel.org>,
        Wedson Almeida Filho <wedsonaf@gmail.com>,
        Alex Gaynor <alex.gaynor@gmail.com>
Subject: Re: [PATCH v2] rust: macros: improve `#[vtable]` documentation
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References: <20231019171540.259173-1-benno.lossin@proton.me> <1cc11492-248e-4b37-9608-b475acde3da2@ryhl.io>
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On 21.10.23 14:45, Alice Ryhl wrote:
> On 10/19/23 19:15, Benno Lossin 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>
>=20
> Reviewed-by: Alice Ryhl <aliceryhl@google.com>
>=20
> There is a minor nit below, and in reviews sent by others, but overall
> this looks fine to me.
>=20
>>    /// # Examples
>>    ///
>>    /// ```ignore
>> +/// # use kernel::error::VTABLE_DEFAULT_ERROR;
>>    /// use kernel::prelude::*;
> I probably wouldn't hide the import of VTABLE_DEFAULT_ERROR from this
> example.

What do you guys think of putting the const it in the prelude?

--=20
Cheers,
Benno