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[180.53.81.189]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2e392ed1a4fsm2885691a91.17.2024.10.15.20.53.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Oct 2024 20:53:44 -0700 (PDT) From: FUJITA Tomonori To: netdev@vger.kernel.org Cc: rust-for-linux@vger.kernel.org, andrew@lunn.ch, hkallweit1@gmail.com, tmgross@umich.edu, ojeda@kernel.org, alex.gaynor@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, a.hindborg@samsung.com, aliceryhl@google.com, anna-maria@linutronix.de, frederic@kernel.org, tglx@linutronix.de, arnd@arndb.de, jstultz@google.com, sboyd@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next v3 2/8] rust: time: Introduce Delta type Date: Wed, 16 Oct 2024 12:52:07 +0900 Message-ID: <20241016035214.2229-3-fujita.tomonori@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241016035214.2229-1-fujita.tomonori@gmail.com> References: <20241016035214.2229-1-fujita.tomonori@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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. Delta::from_[micro|millis|secs] APIs take i64. When a span of time overflows, i64::MAX is used. Signed-off-by: FUJITA Tomonori --- rust/kernel/time.rs | 74 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) diff --git a/rust/kernel/time.rs b/rust/kernel/time.rs index 4a7c6037c256..38a70dc98083 100644 --- a/rust/kernel/time.rs +++ b/rust/kernel/time.rs @@ -8,9 +8,15 @@ //! C header: [`include/linux/jiffies.h`](srctree/include/linux/jiffies.h). //! C header: [`include/linux/ktime.h`](srctree/include/linux/ktime.h). =20 +/// The number of nanoseconds per microsecond. +pub const NSEC_PER_USEC: i64 =3D bindings::NSEC_PER_USEC as i64; + /// The number of nanoseconds per millisecond. pub const NSEC_PER_MSEC: i64 =3D bindings::NSEC_PER_MSEC as i64; =20 +/// The number of nanoseconds per second. +pub const NSEC_PER_SEC: i64 =3D bindings::NSEC_PER_SEC as i64; + /// The time unit of Linux kernel. One jiffy equals (1/HZ) second. pub type Jiffies =3D core::ffi::c_ulong; =20 @@ -81,3 +87,71 @@ fn sub(self, other: Ktime) -> Ktime { } } } + +/// A span of time. +#[derive(Copy, Clone)] +pub struct Delta { + nanos: i64, +} + +impl Delta { + /// Create a new `Delta` from a number of nanoseconds. + #[inline] + pub fn from_nanos(nanos: i64) -> Self { + Self { nanos } + } + + /// Create a new `Delta` from a number of microseconds. + #[inline] + pub fn from_micros(micros: i64) -> Self { + Self { + nanos: micros.saturating_mul(NSEC_PER_USEC), + } + } + + /// Create a new `Delta` from a number of milliseconds. + #[inline] + pub fn from_millis(millis: i64) -> Self { + Self { + nanos: millis.saturating_mul(NSEC_PER_MSEC), + } + } + + /// Create a new `Delta` from a number of seconds. + #[inline] + pub fn from_secs(secs: i64) -> Self { + Self { + nanos: secs.saturating_mul(NSEC_PER_SEC), + } + } + + /// Return `true` if the `Detla` spans no time. + #[inline] + pub fn is_zero(self) -> bool { + self.nanos =3D=3D 0 + } + + /// Return the number of nanoseconds in the `Delta`. + #[inline] + pub fn as_nanos(self) -> i64 { + self.nanos + } + + /// Return the number of microseconds in the `Delta`. + #[inline] + pub fn as_micros(self) -> i64 { + self.nanos / NSEC_PER_USEC + } + + /// Return the number of milliseconds in the `Delta`. + #[inline] + pub fn as_millis(self) -> i64 { + self.nanos / NSEC_PER_MSEC + } + + /// Return the number of seconds in the `Delta`. + #[inline] + pub fn as_secs(self) -> i64 { + self.nanos / NSEC_PER_SEC + } +} --=20 2.43.0