linux-kernel - Re: [PATCH v4 24/28] rust: alloc: implement `contains` for `Flags`

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAH5fLgjTRjRx3LYMjSmVUGMa1=kLqcAGfwZO+Q+399fh5FwGOg@mail.gmail.com>
Date: Wed, 7 Aug 2024 15:53:42 +0200
From: Alice Ryhl <aliceryhl@...gle.com>
To: Danilo Krummrich <dakr@...nel.org>
Cc: ojeda@...nel.org, alex.gaynor@...il.com, wedsonaf@...il.com, 
	boqun.feng@...il.com, gary@...yguo.net, bjorn3_gh@...tonmail.com, 
	benno.lossin@...ton.me, a.hindborg@...sung.com, akpm@...ux-foundation.org, 
	daniel.almeida@...labora.com, faith.ekstrand@...labora.com, 
	boris.brezillon@...labora.com, lina@...hilina.net, mcanal@...lia.com, 
	zhiw@...dia.com, acurrid@...dia.com, cjia@...dia.com, jhubbard@...dia.com, 
	airlied@...hat.com, ajanulgu@...hat.com, lyude@...hat.com, 
	linux-kernel@...r.kernel.org, rust-for-linux@...r.kernel.org, 
	linux-mm@...ck.org
Subject: Re: [PATCH v4 24/28] rust: alloc: implement `contains` for `Flags`

On Mon, Aug 5, 2024 at 5:22 PM Danilo Krummrich <dakr@...nel.org> wrote:
>
> Provide a simple helper function to check whether given flags do
> contain one or multiple other flags.
>
> This is used by a subsequent patch implementing the Cmalloc `Allocator`
> to check for __GFP_ZERO.
>
> Signed-off-by: Danilo Krummrich <dakr@...nel.org>

One nit, but:

Reviewed-by: Alice Ryhl <aliceryhl@...gle.com>

>  rust/kernel/alloc.rs | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/rust/kernel/alloc.rs b/rust/kernel/alloc.rs
> index 8a1cecc20d09..615afe69d097 100644
> --- a/rust/kernel/alloc.rs
> +++ b/rust/kernel/alloc.rs
> @@ -34,7 +34,7 @@
>  /// They can be combined with the operators `|`, `&`, and `!`.
>  ///
>  /// Values can be used from the [`flags`] module.
> -#[derive(Clone, Copy)]
> +#[derive(Clone, Copy, PartialEq)]
>  pub struct Flags(u32);
>
>  impl Flags {
> @@ -42,6 +42,11 @@ impl Flags {
>      pub(crate) fn as_raw(self) -> u32 {
>          self.0
>      }
> +
> +    /// Check whether `flags` is contained in `self`.
> +    pub fn contains(&self, flags: Flags) -> bool {
> +        (*self & flags) == flags
> +    }

Since this type is Copy, you can do this:

pub fn contains(self, flags: Flags) -> bool {
    (self & flags) == flags
}

and avoid the asterisk.

Alice