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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Wed, 14 Apr 2021 13:21:52 -0700
Message-ID: <CAHk-=wgdhVW3+YFHG5Le=mZMYf3mGjgv1f-Td=254bj9fYd7fg@mail.gmail.com>
Subject: Re: [PATCH 00/13] [RFC] Rust support
To:     Matthew Wilcox <willy@infradead.org>
Cc:     ojeda@kernel.org, Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        rust-for-linux@vger.kernel.org,
        Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Wed, Apr 14, 2021 at 1:10 PM Matthew Wilcox <willy@infradead.org> wrote:
>
> There's a philosophical point to be discussed here which you're skating
> right over!  Should rust-in-the-linux-kernel provide the same memory
> allocation APIs as the rust-standard-library, or should it provide a Rusty
> API to the standard-linux-memory-allocation APIs?

Yeah, I think that the standard Rust API may simply not be acceptable
inside the kernel, if it has similar behavior to the (completely
broken) C++ "new" operator.

So anything that does "panic!" in the normal Rust API model needs to
be (statically) caught, and never exposed as an actual call to
"panic()/BUG()" in the kernel.

So "Result<T, E>" is basically the way to go, and if the standard Rust
library alloc() model is based on "panic!" then that kind of model
must simply not be used in the kernel.

             Linus

           Linus