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 8 use crate::types::Opaque; 9 10 mod arc; 11 mod condvar; 12 pub mod lock; 13 mod locked_by; 14 pub mod poll; 15 pub mod rcu; 16 17 pub use arc::{Arc, ArcBorrow, UniqueArc}; 18 pub use condvar::{new_condvar, CondVar, CondVarTimeoutResult}; 19 pub use lock::global::{global_lock, GlobalGuard, GlobalLock, GlobalLockBackend, GlobalLockedBy}; 20 pub use lock::mutex::{new_mutex, Mutex, MutexGuard}; 21 pub use lock::spinlock::{new_spinlock, SpinLock, SpinLockGuard}; 22 pub use locked_by::LockedBy; 23 24 /// Represents a lockdep class. It's a wrapper around C's `lock_class_key`. 25 #[repr(transparent)] 26 pub struct LockClassKey(Opaque<bindings::lock_class_key>); 27 28 // SAFETY: `bindings::lock_class_key` is designed to be used concurrently from multiple threads and 29 // provides its own synchronization. 30 unsafe impl Sync for LockClassKey {} 31 32 impl LockClassKey { 33 /// Creates a new lock class key. 34 pub const fn new() -> Self { 35 Self(Opaque::uninit()) 36 } 37 38 pub(crate) fn as_ptr(&self) -> *mut bindings::lock_class_key { 39 self.0.get() 40 } 41 } 42 43 impl Default for LockClassKey { 44 fn default() -> Self { 45 Self::new() 46 } 47 } 48 49 /// Defines a new static lock class and returns a pointer to it. 50 #[doc(hidden)] 51 #[macro_export] 52 macro_rules! static_lock_class { 53 () => {{ 54 static CLASS: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new(); 55 &CLASS 56 }}; 57 } 58 59 /// Returns the given string, if one is provided, otherwise generates one based on the source code 60 /// location. 61 #[doc(hidden)] 62 #[macro_export] 63 macro_rules! optional_name { 64 () => { 65 $crate::c_str!(::core::concat!(::core::file!(), ":", ::core::line!())) 66 }; 67 ($name:literal) => { 68 $crate::c_str!($name) 69 }; 70 } 71