Re: [PATCH v5 4/7] rust: time: add Delta::to_jiffies() for timeout conversion

Andreas Hindborg <[email protected]> Thu, 06 Aug 2026 11:50:35 +0200
Newsgroups org.kernel.vger.rust-for-linux
Message-ID <[email protected]>
FUJITA Tomonori <[email protected]> writes:

> From: FUJITA Tomonori <[email protected]>
>
> Add Delta<Nsec>::to_jiffies() conversion that rounds up so the
> resulting timeout is never shorter than the requested span, clamps a
> negative span to an immediate timeout, and saturates an overlong span
> to the kernel's MAX_JIFFY_OFFSET "wait forever" value.
>
> Reviewed-by: Gary Guo <[email protected]>
> Signed-off-by: FUJITA Tomonori <[email protected]>
> ---
>  rust/kernel/time.rs | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
>
> diff --git a/rust/kernel/time.rs b/rust/kernel/time.rs
> index 9d65a6c1992a..5844ee985a7b 100644
> --- a/rust/kernel/time.rs
> +++ b/rust/kernel/time.rs
> @@ -551,6 +551,27 @@ pub fn as_millis_ceil(self) -> i64 {
>          }
>      }
>  
> +    /// Convert this span to a [`Delta<Jiffy>`] suitable for use as a timeout.
> +    ///
> +    /// The value is rounded up to the next whole jiffy, so the resulting
> +    /// timeout is never shorter than `self` (as `msecs_to_jiffies()` does).
> +    /// A negative span clamps to zero jiffies (an immediate timeout).

Should we rename this to `to_jiffies_timeout` to indicate the clamping
logic more clearly? I would expect a function with this name to have a
negative `Delta<Nsec>` convert to a negative `Delta<Jiffy>`.

Best regards,
Andreas Hindborg