linux-kernel - Re: [PATCH] rust/time: Add Delta::from

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: <20251117.203843.1397954301918831869.fujita.tomonori@gmail.com>
Date: Mon, 17 Nov 2025 20:38:43 +0900 (JST)
From: FUJITA Tomonori <fujita.tomonori@...il.com>
To: a.hindborg@...nel.org
Cc: fujita.tomonori@...il.com, lyude@...hat.com,
 rust-for-linux@...r.kernel.org, linux-kernel@...r.kernel.org,
 boqun.feng@...il.com, frederic@...nel.org, tglx@...utronix.de,
 anna-maria@...utronix.de, jstultz@...gle.com, sboyd@...nel.org,
 ojeda@...nel.org, alex.gaynor@...il.com, gary@...yguo.net,
 bjorn3_gh@...tonmail.com, lossin@...nel.org, aliceryhl@...gle.com,
 tmgross@...ch.edu, dakr@...nel.org
Subject: Re: [PATCH] rust/time: Add Delta::from_nanos()

On Mon, 17 Nov 2025 12:15:53 +0100
Andreas Hindborg <a.hindborg@...nel.org> wrote:

>>> diff --git a/rust/kernel/time.rs b/rust/kernel/time.rs
>>> index 6ea98dfcd0278..2b096e5a61cda 100644
>>> --- a/rust/kernel/time.rs
>>> +++ b/rust/kernel/time.rs
>>> @@ -363,6 +363,12 @@ impl Delta {
>>>      /// A span of time equal to zero.
>>>      pub const ZERO: Self = Self { nanos: 0 };
>>>
>>> +    /// Create a new [`Delta`] from a number of nanoseconds.
>>> +    #[inline]
>>> +    pub const fn from_nanos(nanos: i64) -> Self {
>>> +        Self { nanos }
>>> +    }
>>> +
>>>      /// Create a new [`Delta`] from a number of microseconds.
>>>      ///
>>>      /// The `micros` can range from -9_223_372_036_854_775 to 9_223_372_036_854_775.
>>
>> For consistency with the other methods, perhaps we should also mention
>> the valid nanos range in the comment?
> 
> But, please make it a constant instead of an integer literal.

Do you mean making the comment of Delta's from_* methods like the
following?

diff --git a/rust/kernel/time.rs b/rust/kernel/time.rs
index 6ea98dfcd027..822746e552fb 100644
--- a/rust/kernel/time.rs
+++ b/rust/kernel/time.rs
@@ -363,9 +363,14 @@ impl Delta {
     /// A span of time equal to zero.
     pub const ZERO: Self = Self { nanos: 0 };
 
+    /// The minimum number of microseconds that can be represented by a [`Delta`].
+    pub const MIN_MICROS: i64 = -9_223_372_036_854_775;
+    /// The maximum number of microseconds that can be represented by a [`Delta`].
+    pub const MAX_MICROS: i64 = 9_223_372_036_854_775;
+
     /// Create a new [`Delta`] from a number of microseconds.
     ///
-    /// The `micros` can range from -9_223_372_036_854_775 to 9_223_372_036_854_775.
+    /// The `micros` can range from [`Delta::MIN_MICROS`] to [`Delta::MAX_MICROS`].
     /// If `micros` is outside this range, `i64::MIN` is used for negative values,
     /// and `i64::MAX` is used for positive values due to saturation.
     #[inline]