linux-kernel - Re: [PATCH v13 3/5] rust: time: Introduce Instant type

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: <67fc517b.050a0220.301460.dfe7@mx.google.com>
Date: Sun, 13 Apr 2025 17:06:15 -0700
From: Boqun Feng <boqun.feng@...il.com>
To: FUJITA Tomonori <fujita.tomonori@...il.com>
Cc: rust-for-linux@...r.kernel.org, Gary Guo <gary@...yguo.net>,
	Fiona Behrens <me@...enk.dev>,
	Daniel Almeida <daniel.almeida@...labora.com>,
	Andreas Hindborg <a.hindborg@...nel.org>,
	linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
	andrew@...n.ch, hkallweit1@...il.com, tmgross@...ch.edu,
	ojeda@...nel.org, alex.gaynor@...il.com, bjorn3_gh@...tonmail.com,
	benno.lossin@...ton.me, a.hindborg@...sung.com,
	aliceryhl@...gle.com, anna-maria@...utronix.de, frederic@...nel.org,
	tglx@...utronix.de, arnd@...db.de, jstultz@...gle.com,
	sboyd@...nel.org, mingo@...hat.com, peterz@...radead.org,
	juri.lelli@...hat.com, vincent.guittot@...aro.org,
	dietmar.eggemann@....com, rostedt@...dmis.org, bsegall@...gle.com,
	mgorman@...e.de, vschneid@...hat.com, tgunders@...hat.com,
	david.laight.linux@...il.com
Subject: Re: [PATCH v13 3/5] rust: time: Introduce Instant type

On Sun, Apr 13, 2025 at 07:43:08PM +0900, FUJITA Tomonori wrote:
> Introduce a type representing a specific point in time. We could use
> the Ktime type but C's ktime_t is used for both timestamp and
> timedelta. To avoid confusion, introduce a new Instant type for
> timestamp.
> 
> Rename Ktime to Instant and modify their methods for timestamp.
> 
> Implement the subtraction operator for Instant:
> 
> Delta = Instant A - Instant B
> 
> Reviewed-by: Boqun Feng <boqun.feng@...il.com>

I probably need to drop my Reviewed-by because of something below:

> Reviewed-by: Gary Guo <gary@...yguo.net>
> Reviewed-by: Fiona Behrens <me@...enk.dev>
> Tested-by: Daniel Almeida <daniel.almeida@...labora.com>
> Reviewed-by: Andreas Hindborg <a.hindborg@...nel.org>
> Signed-off-by: FUJITA Tomonori <fujita.tomonori@...il.com>
> ---
[...]
> diff --git a/rust/kernel/time/hrtimer.rs b/rust/kernel/time/hrtimer.rs
> index ce53f8579d18..27243eaaf8ed 100644
> --- a/rust/kernel/time/hrtimer.rs
> +++ b/rust/kernel/time/hrtimer.rs
> @@ -68,7 +68,7 @@
>  //! `start` operation.
>  
>  use super::ClockId;
> -use crate::{prelude::*, time::Ktime, types::Opaque};
> +use crate::{prelude::*, time::Instant, types::Opaque};
>  use core::marker::PhantomData;
>  use pin_init::PinInit;
>  
> @@ -189,7 +189,7 @@ pub trait HrTimerPointer: Sync + Sized {
>  
>      /// Start the timer with expiry after `expires` time units. If the timer was
>      /// already running, it is restarted with the new expiry time.
> -    fn start(self, expires: Ktime) -> Self::TimerHandle;
> +    fn start(self, expires: Instant) -> Self::TimerHandle;

We should be able to use what I suggested:

	https://lore.kernel.org/rust-for-linux/Z_ALZsnwN53ZPBrB@boqun-archlinux/	

to make different timer modes (rel or abs) choose different expire type.

I don't think we can merge this patch as it is, unfortunately, because
it doesn't make sense for a relative timer to take an Instant as expires
value.

Regards,
Boqun

>  }
>  
[...]