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::CondVar;
17pub use lock::{mutex::Mutex, spinlock::SpinLock};
18pub use locked_by::LockedBy;
19
20/// Represents a lockdep class. It's a wrapper around C's `lock_class_key`.
21#[repr(transparent)]
22pub struct LockClassKey(Opaque<bindings::lock_class_key>);
23
24// SAFETY: `bindings::lock_class_key` is designed to be used concurrently from multiple threads and
25// provides its own synchronization.
26unsafe impl Sync for LockClassKey {}
27
28impl LockClassKey {
29    /// Creates a new lock class key.
30    pub const fn new() -> Self {
31        Self(Opaque::uninit())
32    }
33
34    pub(crate) fn as_ptr(&self) -> *mut bindings::lock_class_key {
35        self.0.get()
36    }
37}
38
39/// Defines a new static lock class and returns a pointer to it.
40#[doc(hidden)]
41#[macro_export]
42macro_rules! static_lock_class {
43    () => {{
44        static CLASS: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
45        &CLASS
46    }};
47}
48
49/// Returns the given string, if one is provided, otherwise generates one based on the source code
50/// location.
51#[doc(hidden)]
52#[macro_export]
53macro_rules! optional_name {
54    () => {
55        $crate::c_str!(::core::concat!(::core::file!(), ":", ::core::line!()))
56    };
57    ($name:literal) => {
58        $crate::c_str!($name)
59    };
60}