Re: [PATCH v8 2/7] rust: time: Introduce Delta type

[Alice Ryhl]

On Thu, Jan 16, 2025 at 5:42 AM FUJITA Tomonori
<fujita.tomonori@xxxxxxxxx> wrote:
>
> Introduce a type representing a span of time. Define our own type
> because `core::time::Duration` is large and could panic during
> creation.
>
> time::Ktime could be also used for time duration but timestamp and
> timedelta are different so better to use a new type.
>
> i64 is used instead of u64 to represent a span of time; some C drivers
> uses negative Deltas and i64 is more compatible with Ktime using i64
> too (e.g., ktime_[us|ms]_delta() APIs return i64 so we create Delta
> object without type conversion.
>
> i64 is used instead of bindings::ktime_t because when the ktime_t
> type is used as timestamp, it represents values from 0 to
> KTIME_MAX, which different from Delta.
>
> Delta::from_[millis|secs] APIs take i64. When a span of time
> overflows, i64::MAX is used.
>
> Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
> Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxx>

One nit below, otherwise LGTM

Reviewed-by: Alice Ryhl <aliceryhl@xxxxxxxxxx>

> +    /// Return the number of nanoseconds in the `Delta`.
> +    #[inline]
> +    pub fn as_nanos(self) -> i64 {
> +        self.nanos
> +    }

I added the ktime_ms_delta() function because I was going to use it.
Can you add an `as_millis()` function too? That way I can use
start_time.elapsed().as_millis() for my use-case.

Alice