linux-kernel - Re: [PATCH v3 0/5] rust: time: Convert hrtimer to use Instant and Delta

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: <20250617.070708.74052163124048514.fujita.tomonori@gmail.com>
Date: Tue, 17 Jun 2025 07:07:08 +0900 (JST)
From: FUJITA Tomonori <fujita.tomonori@...il.com>
To: a.hindborg@...nel.org
Cc: alex.gaynor@...il.com, ojeda@...nel.org, aliceryhl@...gle.com,
 anna-maria@...utronix.de, bjorn3_gh@...tonmail.com, boqun.feng@...il.com,
 dakr@...nel.org, frederic@...nel.org, gary@...yguo.net,
 jstultz@...gle.com, linux-kernel@...r.kernel.org, lossin@...nel.org,
 lyude@...hat.com, rust-for-linux@...r.kernel.org, sboyd@...nel.org,
 tglx@...utronix.de, tmgross@...ch.edu
Subject: Re: [PATCH v3 0/5] rust: time: Convert hrtimer to use Instant and
 Delta

On Tue, 10 Jun 2025 22:28:18 +0900
FUJITA Tomonori <fujita.tomonori@...il.com> wrote:

> Convert hrtimer to use `Instant` and `Delta`; remove the use of
> `Ktime` from the hrtimer code, which was originally introduced as a
> temporary workaround.
> 
> hrtimer uses either an `Instant` or a `Delta` as its expiration value,
> depending on the mode specified at creation time. This patchset
> replaces `HrTimerMode` enum with a trait-based abstraction and
> associates each mode with either an `Instant` or a `Delta`. By
> leveraging Rust's type system, this change enables `HrTimer` to be
> statically associated with a specific `HrTimerMode`, the corresponding
> `Instant` or `Delta`, and a `ClockSource`.
> 
> The `impl_has_hr_timer` macro is extended to allow specifying the
> `HrTimerMode`. In the following example, it guarantees that the
> `start()` method for `Foo` only accepts `Instant<Monotonic>`. Using a
> `Delta` or an `Instant` with a different clock source will result in a
> compile-time error:
> 
> struct Foo {
>     #[pin]
>     timer: HrTimer<Self>,
> }
> 
> impl_has_hr_timer! {
>     impl HasHrTimer<Self> for Foo {
>         mode : AbsoluteMode<Monotonic>,
>         field : self.timer
>     }
> }
> 
> This design eliminates runtime mismatches between expires types and
> clock sources, and enables stronger type-level guarantees throughout
> hrtimer.
> 
> This patchset can be applied on top of the typed clock sources patchset (v4):
> 
> https://lore.kernel.org/lkml/20250610093258.3435874-1-fujita.tomonori@gmail.com/

Andreas, whenever you get a chance, could you create a
timekeeping-next branch and merge the typed clock sources patchset and
this?

That would make it easier for me to work on top of them.

Thanks a lot for the review!