Received-SPF: pass (google.com: domain of linux-kernel+bounces-134971-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.48.161 as permitted sender) client-ip=147.75.48.161;
Precedence: bulk
MIME-Version: 1.0
References: <20240404-alice-mm-v4-0-49a84242cf02@google.com>
 <20240404-alice-mm-v4-4-49a84242cf02@google.com> <a48b2347-b58b-432e-bdb8-d5449016ab57@proton.me>
 <CAH5fLgg3wpcDE+n6nd0CGtDzyXSrD2nLhY8RxdTHjAD8hQ9VDQ@mail.gmail.com> <c130a6f5-77d7-4d9e-984d-7a8bf48ff918@proton.me>
In-Reply-To: <c130a6f5-77d7-4d9e-984d-7a8bf48ff918@proton.me>
From: Alice Ryhl <aliceryhl@google.com>
Date: Mon, 8 Apr 2024 09:54:40 +0200
Message-ID: <CAH5fLgigLV17+6U75MC43XFnYeqtgvrrTWD7JmDSB-ebNjCVvw@mail.gmail.com>
Subject: Re: [PATCH v4 4/4] rust: add abstraction for `struct page`
To: Benno Lossin <benno.lossin@proton.me>
Cc: Miguel Ojeda <ojeda@kernel.org>, Matthew Wilcox <willy@infradead.org>, 
	Al Viro <viro@zeniv.linux.org.uk>, Andrew Morton <akpm@linux-foundation.org>, 
	Kees Cook <keescook@chromium.org>, Alex Gaynor <alex.gaynor@gmail.com>, 
	Wedson Almeida Filho <wedsonaf@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 <a.hindborg@samsung.com>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, 
	=?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= <arve@android.com>, 
	Todd Kjos <tkjos@android.com>, Martijn Coenen <maco@android.com>, 
	Joel Fernandes <joel@joelfernandes.org>, Carlos Llamas <cmllamas@google.com>, 
	Suren Baghdasaryan <surenb@google.com>, Arnd Bergmann <arnd@arndb.de>, linux-mm@kvack.org, 
	linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, 
	Christian Brauner <brauner@kernel.org>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

On Sun, Apr 7, 2024 at 10:59=E2=80=AFAM Benno Lossin <benno.lossin@proton.m=
e> wrote:
>
> On 05.04.24 09:44, Alice Ryhl wrote:
> > On Fri, Apr 5, 2024 at 12:33=E2=80=AFAM Benno Lossin <benno.lossin@prot=
on.me> wrote:
> >>
> >> On 04.04.24 14:31, Alice Ryhl wrote:
> >>> +/// A bitwise shift for the page size.
> >>> +#[allow(clippy::unnecessary_cast)]
> >>
> >> Why can't you remove the cast?
> >
> > Bindgen could decide to use a different type in the future or on
> > different platforms.
>
> Did that already happen?
>
> I think that we might want to know if the type changes, since then the
> value might change?

I mean, it's quite unlikely that the page size will not fit in an
usize, even if it changes?

From bindgen's point of view, this constant is just an integer literal
with no type information. So I don't see how we can expect it to
always be generated as a usize?

Alice