From d481d999967d4e7ebcecf472fc29b8f5dfcfcc29 Mon Sep 17 00:00:00 2001 From: FUJITA Tomonori Date: Sat, 8 Aug 2026 15:28:35 +0900 Subject: rust: time: add Delta::as_millis_ceil() Add a ceiling variant, mirroring the existing as_micros_ceil() since the existing as_millis() truncates towards zero. Reviewed-by: Gary Guo Signed-off-by: FUJITA Tomonori Reviewed-by: Andreas Hindborg Link: https://patch.msgid.link/20260808062839.1159990-4-tomo@flapping.org Signed-off-by: Miguel Ojeda --- rust/kernel/time.rs | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'rust') diff --git a/rust/kernel/time.rs b/rust/kernel/time.rs index 53b77abcb317..6c0a5e8090d0 100644 --- a/rust/kernel/time.rs +++ b/rust/kernel/time.rs @@ -528,6 +528,32 @@ impl Delta { } } + /// Return the smallest number of milliseconds greater than or equal + /// to the value in the [`Delta`]. + #[inline] + pub fn as_millis_ceil(self) -> i64 { + // Only positive values need to be rounded up: truncating division already + // rounds towards zero, i.e. up, for negative values. + // + // The usual `(nanos + d - 1) / d` is not used because the addition overflows + // once `nanos` exceeds `i64::MAX - (d - 1)`; saturating the addition instead + // would drop the rounding bias and return a result one unit too small. + let n = self.as_nanos(); + + let (n, add) = if n > 0 { (n - 1, 1) } else { (n, 0) }; + + #[cfg(CONFIG_64BIT)] + { + n / NSEC_PER_MSEC + add + } + + #[cfg(not(CONFIG_64BIT))] + // SAFETY: It is always safe to call `ktime_to_ms()` with any value. + unsafe { + bindings::ktime_to_ms(n) + add + } + } + /// Return `self % dividend` where `dividend` is in nanoseconds. /// /// The kernel doesn't have any emulation for `s64 % s64` on 32 bit platforms, so this is -- cgit v1.2.3