1// SPDX-License-Identifier: GPL-2.0
 2
 3//! Synchronisation primitives.
 4//!
 5//! This module contains the kernel APIs related to synchronisation that have been ported or
 6//! wrapped for usage by Rust code in the kernel.
 7
 8use crate::types::Opaque;
 9
10mod arc;
11mod condvar;
12pub mod lock;
13mod locked_by;
14
15pub use arc::{Arc, ArcBorrow, UniqueArc};
16pub use condvar::{new_condvar, CondVar, CondVarTimeoutResult};
17pub use lock::mutex::{new_mutex, Mutex};
18pub use lock::spinlock::{new_spinlock, SpinLock};
19pub use locked_by::LockedBy;
20
21/// Represents a lockdep class. It's a wrapper around C's `lock_class_key`.
22#[repr(transparent)]
23pub struct LockClassKey(Opaque<bindings::lock_class_key>);
24
25// SAFETY: `bindings::lock_class_key` is designed to be used concurrently from multiple threads and
26// provides its own synchronization.
27unsafe impl Sync for LockClassKey {}
28
29impl LockClassKey {
30    /// Creates a new lock class key.
31    pub const fn new() -> Self {
32        Self(Opaque::uninit())
33    }
34
35    pub(crate) fn as_ptr(&self) -> *mut bindings::lock_class_key {
36        self.0.get()
37    }
38}
39
40/// Defines a new static lock class and returns a pointer to it.
41#[doc(hidden)]
42#[macro_export]
43macro_rules! static_lock_class {
44    () => {{
45        static CLASS: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
46        &CLASS
47    }};
48}
49
50/// Returns the given string, if one is provided, otherwise generates one based on the source code
51/// location.
52#[doc(hidden)]
53#[macro_export]
54macro_rules! optional_name {
55    () => {
56        $crate::c_str!(::core::concat!(::core::file!(), ":", ::core::line!()))
57    };
58    ($name:literal) => {
59        $crate::c_str!($name)
60    };
61}