From 82e170874849c4c57dba6b4ee1a08fae1c0a5f02 Mon Sep 17 00:00:00 2001 From: Alice Ryhl Date: Mon, 8 Jan 2024 14:49:58 +0000 Subject: rust: time: add msecs to jiffies conversion Defines type aliases and conversions for msecs and jiffies. This is used by Rust Binder for process freezing. There, we want to sleep until the freeze operation completes, but we want to be able to abort the process freezing if it doesn't complete within some timeout. The freeze timeout is supplied in msecs. Note that we need to convert to jiffies in Binder. It is not enough to introduce a variant of `CondVar::wait_timeout` that takes the timeout in msecs because we need to be able to restart the sleep with the remaining sleep duration if it is interrupted, and if the API takes msecs rather than jiffies, then that would require a conversion roundtrip jiffies-> msecs->jiffies that is best avoided. Suggested-by: Boqun Feng Reviewed-by: Boqun Feng Reviewed-by: Benno Lossin Reviewed-by: Martin Rodriguez Reboredo Reviewed-by: Tiago Lam Signed-off-by: Alice Ryhl Link: https://lore.kernel.org/r/20240108-rb-new-condvar-methods-v4-2-88e0c871cc05@google.com Signed-off-by: Miguel Ojeda --- rust/kernel/time.rs | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) create mode 100644 rust/kernel/time.rs (limited to 'rust/kernel/time.rs') diff --git a/rust/kernel/time.rs b/rust/kernel/time.rs new file mode 100644 index 000000000000..25a896eed468 --- /dev/null +++ b/rust/kernel/time.rs @@ -0,0 +1,20 @@ +// 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. + +/// 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) } +} -- cgit v1.2.3-70-g09d2