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