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// SPDX-License-Identifier: GPL-2.0
//! Time related primitives.
//!
//! This module contains the kernel APIs related to time and timers that
//! have been ported or wrapped for usage by Rust code in the kernel.
//!
//! C header: [`include/linux/jiffies.h`](srctree/include/linux/jiffies.h).
//! C header: [`include/linux/ktime.h`](srctree/include/linux/ktime.h).
/// The number of nanoseconds per millisecond.
pub const NSEC_PER_MSEC: i64 = bindings::NSEC_PER_MSEC as i64;
/// The time unit of Linux kernel. One jiffy equals (1/HZ) second.
pub type Jiffies = core::ffi::c_ulong;
/// The millisecond time unit.
pub type Msecs = core::ffi::c_uint;
/// Converts milliseconds to jiffies.
#[inline]
pub fn msecs_to_jiffies(msecs: Msecs) -> Jiffies {
// SAFETY: The `__msecs_to_jiffies` function is always safe to call no
// matter what the argument is.
unsafe { bindings::__msecs_to_jiffies(msecs) }
}
/// A Rust wrapper around a `ktime_t`.
#[repr(transparent)]
#[derive(Copy, Clone)]
pub struct Ktime {
inner: bindings::ktime_t,
}
impl Ktime {
/// Create a `Ktime` from a raw `ktime_t`.
#[inline]
pub fn from_raw(inner: bindings::ktime_t) -> Self {
Self { inner }
}
/// Get the current time using `CLOCK_MONOTONIC`.
#[inline]
pub fn ktime_get() -> Self {
// SAFETY: It is always safe to call `ktime_get` outside of NMI context.
Self::from_raw(unsafe { bindings::ktime_get() })
}
/// Divide the number of nanoseconds by a compile-time constant.
#[inline]
fn divns_constant<const DIV: i64>(self) -> i64 {
self.to_ns() / DIV
}
/// Returns the number of nanoseconds.
#[inline]
pub fn to_ns(self) -> i64 {
self.inner
}
/// Returns the number of milliseconds.
#[inline]
pub fn to_ms(self) -> i64 {
self.divns_constant::<NSEC_PER_MSEC>()
}
}
/// Returns the number of milliseconds between two ktimes.
#[inline]
pub fn ktime_ms_delta(later: Ktime, earlier: Ktime) -> i64 {
(later - earlier).to_ms()
}
impl core::ops::Sub for Ktime {
type Output = Ktime;
#[inline]
fn sub(self, other: Ktime) -> Ktime {
Self {
inner: self.inner - other.inner,
}
}
}
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