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From:   Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Date:   Thu, 10 Aug 2023 09:56:18 +0200
Message-ID: <CANiq72=-NffQz9jMxoznoRGkeQz+1oTb6__r3c1z+BzOsWxfRw@mail.gmail.com>
Subject: Re: [PATCH] rust: macros: add `paste!` proc macro
To:     Greg KH <gregkh@linuxfoundation.org>
Cc:     Gary Guo <gary@garyguo.net>, Miguel Ojeda <ojeda@kernel.org>,
        Alex Gaynor <alex.gaynor@gmail.com>,
        Wedson Almeida Filho <wedsonaf@gmail.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        =?UTF-8?Q?Bj=C3=B6rn_Roy_Baron?= <bjorn3_gh@protonmail.com>,
        Benno Lossin <benno.lossin@proton.me>,
        Andreas Hindborg <a.hindborg@samsung.com>,
        Alice Ryhl <aliceryhl@google.com>,
        linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org
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On Thu, Aug 10, 2023 at 7:08=E2=80=AFAM Greg KH <gregkh@linuxfoundation.org=
> wrote:
>
> The kernel will migrate when we have converted all files in the tree to
> SPDX and can worry about things like the SPDX version level.  We have a
> ways to go still...

I see, thanks!

> Be VERY careful with dual licenses please, and especially non-GPL ones
> in the kernel tree.  It gets tricky very very quickly and you need to
> know what you are doing.  So much so that I really want to see a lawyer
> sign off on such a thing so that everyone involved understands the
> issues that this requires.

It is the common one used in Rust projects, which we are using for
other bits too, e.g. vendoring the `alloc` standard library.

Since these couple functions are essentially a compiler plugin (a proc
macro) that is useful in userspace and other contexts too, Gary wanted
to use that license (he contributes the other kernel code under
GPL-2.0). For instance, he may possibly want to put those functions in
crates.io or similar, I imagine (like the linked crate this replaces
as a simplification).

He is also OK with GPL-2.0, so we can just do that here, of course.
But I am mentioning the above because, if this one is problematic,
then perhaps we should revisit again `rust/alloc`, our `std_vendor.rs`
files and the `pinned-init` library (which all use the same dual
license).

> Otherwise please, just default to GPL-2.0 for kernel code, unless you
> have real reasons why it can't be that way, as remember, the overall
> license of the codebase is that.

That is our default, definitely. I OK'd these two functions for the
reasons above only.

Thanks for keeping an eye on our list, by the way.

Cheers,
Miguel