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From:   Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Date:   Tue, 9 May 2023 13:10:54 +0200
Message-ID: <CANiq72=g=CnEQTkc50qozUdOBZECr7Jr2NCRfGFaKh751i6Sww@mail.gmail.com>
Subject: Re: [PATCH v2] rust: error: add missing error codes
To:     Greg KH <gregkh@linuxfoundation.org>
Cc:     Alice Ryhl <aliceryhl@google.com>, gary@garyguo.net,
        alex.gaynor@gmail.com, benno.lossin@proton.me,
        bjorn3_gh@protonmail.com, boqun.feng@gmail.com,
        linux-kernel@vger.kernel.org, ojeda@kernel.org,
        patches@lists.linux.dev, rust-for-linux@vger.kernel.org,
        wedsonaf@gmail.com
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On Tue, May 9, 2023 at 10:46=E2=80=AFAM Greg KH <gregkh@linuxfoundation.org=
> wrote:
>
> It depends on which arch you are building for.  That's why we have
> per-platform errno.h files, the values are different for different ones.
> So you need to handle them all properly somehow.  How is rust going to
> handle per-arch stuff like this?

We can do conditional compilation in the same file, possibly with a
Rust macro which takes a nice table that shows all arches at once.

We can also split into files like C and move it to each `arch/`, there
are a couple of approaches for this. This is best for `MAINTAINERS`,
although these headers almost never change, so it is not a big
advantage.

We could also automatically do everything based on the C headers, too.
Back then it felt to me like too much complexity for little gain,
given those C headers almost never change, but now it may be worth it.
Or, instead, having a test that verifies they are the same instead,
and that way we don't introduce complexity for the build itself.

Alice only needs `ERESTARTSYS` so far, as far as I understand, so
perhaps it is simplest to only add the rest of the non-generic ones
for the moment; and gather opinions on the approaches above meanwhile.

Cheers,
Miguel