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 15 pub use arc::{Arc, ArcBorrow, UniqueArc}; 16 pub use condvar::CondVar; 17 pub use lock::{mutex::Mutex, spinlock::SpinLock}; 18 pub use locked_by::LockedBy; 19 20 /// Represents a lockdep class. It's a wrapper around C's `lock_class_key`. 21 #[repr(transparent)] 22 pub 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. 26 unsafe impl Sync for LockClassKey {} 27 28 impl LockClassKey { as_ptr(&self) -> *mut bindings::lock_class_key29 pub(crate) fn as_ptr(&self) -> *mut bindings::lock_class_key { 30 self.0.get() 31 } 32 } 33 34 /// Defines a new static lock class and returns a pointer to it. 35 #[doc(hidden)] 36 #[macro_export] 37 macro_rules! static_lock_class { 38 () => {{ 39 static CLASS: $crate::sync::LockClassKey = 40 // SAFETY: lockdep expects uninitialized memory when it's handed a statically allocated 41 // lock_class_key 42 unsafe { ::core::mem::MaybeUninit::uninit().assume_init() }; 43 &CLASS 44 }}; 45 } 46 47 /// Returns the given string, if one is provided, otherwise generates one based on the source code 48 /// location. 49 #[doc(hidden)] 50 #[macro_export] 51 macro_rules! optional_name { 52 () => { 53 $crate::c_str!(::core::concat!(::core::file!(), ":", ::core::line!())) 54 }; 55 ($name:literal) => { 56 $crate::c_str!($name) 57 }; 58 } 59