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;
14pub mod poll;
15
16pub use arc::{Arc, ArcBorrow, UniqueArc};
17pub use condvar::{new_condvar, CondVar, CondVarTimeoutResult};
18pub use lock::global::{global_lock, GlobalGuard, GlobalLock, GlobalLockBackend, GlobalLockedBy};
19pub use lock::mutex::{new_mutex, Mutex};
20pub use lock::spinlock::{new_spinlock, SpinLock};
21pub use locked_by::LockedBy;
22
23/// Represents a lockdep class. It's a wrapper around C's `lock_class_key`.
24#[repr(transparent)]
25pub struct LockClassKey(Opaque<bindings::lock_class_key>);
26
27// SAFETY: `bindings::lock_class_key` is designed to be used concurrently from multiple threads and
28// provides its own synchronization.
29unsafe impl Sync for LockClassKey {}
30
31impl LockClassKey {
32    /// Creates a new lock class key.
33    pub const fn new() -> Self {
34        Self(Opaque::uninit())
35    }
36
37    pub(crate) fn as_ptr(&self) -> *mut bindings::lock_class_key {
38        self.0.get()
39    }
40}
41
42impl Default for LockClassKey {
43    fn default() -> Self {
44        Self::new()
45    }
46}
47
48/// Defines a new static lock class and returns a pointer to it.
49#[doc(hidden)]
50#[macro_export]
51macro_rules! static_lock_class {
52    () => {{
53        static CLASS: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
54        &CLASS
55    }};
56}
57
58/// Returns the given string, if one is provided, otherwise generates one based on the source code
59/// location.
60#[doc(hidden)]
61#[macro_export]
62macro_rules! optional_name {
63    () => {
64        $crate::c_str!(::core::concat!(::core::file!(), ":", ::core::line!()))
65    };
66    ($name:literal) => {
67        $crate::c_str!($name)
68    };
69}