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From: Alice Ryhl <aliceryhl@google.com>
Date: Tue, 27 Feb 2024 16:56:51 +0100
Message-ID: <CAH5fLggmaemG8EJamSy6oEDneZAWhJWJ7OrcbG52rdrdukyaxA@mail.gmail.com>
Subject: Re: [PATCH v2 4/4] rust: add abstraction for `struct page`
To: Matthew Wilcox <willy@infradead.org>
Cc: Miguel Ojeda <ojeda@kernel.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>, 
	Benno Lossin <benno.lossin@proton.me>, Andreas Hindborg <a.hindborg@samsung.com>, 
	Kees Cook <keescook@chromium.org>, Al Viro <viro@zeniv.linux.org.uk>, 
	Andrew Morton <akpm@linux-foundation.org>, 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>
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On Tue, Feb 27, 2024 at 4:37=E2=80=AFPM Matthew Wilcox <willy@infradead.org=
> wrote:
>
> On Thu, Feb 08, 2024 at 03:47:54PM +0000, Alice Ryhl wrote:
> > +impl Page {
> > +    /// Allocates a new page.
> > +    pub fn new() -> Result<Self, AllocError> {
> > +        // SAFETY: These are the correct arguments to allocate a singl=
e page.
> > +        let page =3D unsafe {
> > +            bindings::alloc_pages(
> > +                bindings::GFP_KERNEL | bindings::__GFP_ZERO | bindings=
::__GFP_HIGHMEM,
>
> I thought I raised this last time, but this is over-specialised for
> Binder's purposes.  Many places that want to allocate a page want
> different GFP flags from this; they shouldn't even be the default flags.
> So either what you're defining here is a BinderPage, or new() needs
> to take GFP flags.

Ah, yeah, sorry. I never got around to figuring that out.

I can change it to take GFP flags.

Thank you for taking another look!
Alice