linux-kernel - Re: [PATCH v3 1/3] rust: clk: use the type-state pattern

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 for Android: free password hash cracker in your pocket

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

Message-Id: <E786E2B1-E233-45D3-923D-A2DBA54BB166@collabora.com>
Date: Tue, 3 Feb 2026 10:37:15 -0300
From: Daniel Almeida <daniel.almeida@...labora.com>
To: Boris Brezillon <boris.brezillon@...labora.com>
Cc: Gary Guo <gary@...yguo.net>,
 "Rafael J. Wysocki" <rafael@...nel.org>,
 Viresh Kumar <viresh.kumar@...aro.org>,
 Danilo Krummrich <dakr@...nel.org>,
 Alice Ryhl <aliceryhl@...gle.com>,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>,
 Thomas Zimmermann <tzimmermann@...e.de>,
 David Airlie <airlied@...il.com>,
 Simona Vetter <simona@...ll.ch>,
 Drew Fustini <fustini@...nel.org>,
 Guo Ren <guoren@...nel.org>,
 Fu Wei <wefu@...hat.com>,
 Uwe Kleine-König <ukleinek@...nel.org>,
 Michael Turquette <mturquette@...libre.com>,
 Stephen Boyd <sboyd@...nel.org>,
 Miguel Ojeda <ojeda@...nel.org>,
 Boqun Feng <boqun.feng@...il.com>,
 Björn Roy Baron <bjorn3_gh@...tonmail.com>,
 Benno Lossin <lossin@...nel.org>,
 Andreas Hindborg <a.hindborg@...nel.org>,
 Trevor Gross <tmgross@...ch.edu>,
 linux-pm@...r.kernel.org,
 linux-kernel@...r.kernel.org,
 dri-devel@...ts.freedesktop.org,
 linux-riscv@...ts.infradead.org,
 linux-pwm@...r.kernel.org,
 linux-clk@...r.kernel.org,
 rust-for-linux@...r.kernel.org
Subject: Re: [PATCH v3 1/3] rust: clk: use the type-state pattern

> On 3 Feb 2026, at 06:09, Boris Brezillon <boris.brezillon@...labora.com> wrote:
> 
> Hello Daniel,
> 
> On Mon, 2 Feb 2026 17:10:38 +0100
> Boris Brezillon <boris.brezillon@...labora.com> wrote:
> 
>>>> -#[pin_data(PinnedDrop)]
>>>> +#[pin_data]
>>>> pub(crate) struct TyrData {
>>>>     pub(crate) pdev: ARef<platform::Device>,
>>>> 
>>>> @@ -92,13 +92,9 @@ fn probe(
>>>>         pdev: &platform::Device<Core>,
>>>>         _info: Option<&Self::IdInfo>,
>>>>     ) -> impl PinInit<Self, Error> {
>>>> -        let core_clk = Clk::get(pdev.as_ref(), Some(c_str!("core")))?;
>>>> -        let stacks_clk = OptionalClk::get(pdev.as_ref(), Some(c_str!("stacks")))?;
>>>> -        let coregroup_clk = OptionalClk::get(pdev.as_ref(), Some(c_str!("coregroup")))?;
>>>> -
>>>> -        core_clk.prepare_enable()?;
>>>> -        stacks_clk.prepare_enable()?;
>>>> -        coregroup_clk.prepare_enable()?;
>>>> +        let core_clk = Clk::<Enabled>::get(pdev.as_ref(), Some(c_str!("core")))?;    
>>> 
>>> Ah, more turbofish.. I'd really want to avoid them if possible.
>>> 
>>> Any disadvantage on just ask the user to chain `.get().prepare_enable()?`? This
>>> way it is also clear that some action is performed.  
>> 
>> I've just disc
> 
> Sorry, I've hit the reply button before I had finished writing my
> answer. So I was about to say that I had started writing something
> similar without knowing this series existed, and I feel like we'd don't
> really need those prepare_enable() shortcuts that exist in C. We might
> has well just go:
> 
> Clk::get(dev, Some(c_str!("core"))).prepare()?.enable()?;
> 
> and have the following variant-specofoc functions
> 
> - Clk<Unprepared>::get[_optional]() (no get on Prepared and Enabled
>  variants)
> - Clk<Unprepared>::prepare()
> - Clk<Prepared>::{enable,unprepare}()
> - Clk<Enabled>::{disable}()
> 
> Regards,
> 
> Boris
> 
> 

I don’t understand how is this better than the turbofish we currently have.

In other words, how is this:

Clk::get(dev, Some(c_str!("core"))).prepare()?.enable()?;

Better than this:

Clk::<Enabled>::get(/*…*/);

— Daniel