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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105// SPDX-License-Identifier: GPL-2.0
//! Memory orderings.//!//! The semantics of these orderings follows the [`LKMM`] definitions and rules.//!//! - [`Acquire`] provides ordering between the load part of the annotated operation and all the//! following memory accesses, and if there is a store part, the store part has the [`Relaxed`]//! ordering.//! - [`Release`] provides ordering between all the preceding memory accesses and the store part of//! the annotated operation, and if there is a load part, the load part has the [`Relaxed`]//! ordering.//! - [`Full`] means "fully-ordered", that is://! - It provides ordering between all the preceding memory accesses and the annotated operation.//! - It provides ordering between the annotated operation and all the following memory accesses.//! - It provides ordering between all the preceding memory accesses and all the following memory//! accesses.//! - All the orderings are the same strength as a full memory barrier (i.e. `smp_mb()`).//! - [`Relaxed`] provides no ordering except the dependency orderings. Dependency orderings are//! described in "DEPENDENCY RELATIONS" in [`LKMM`]'s [`explanation`].//!//! [`LKMM`]: srctree/tools/memory-model///! [`explanation`]: srctree/tools/memory-model/Documentation/explanation.txt
/// The annotation type for relaxed memory ordering, for the description of relaxed memory/// ordering, see [module-level documentation].////// [module-level documentation]: crate::sync::atomic::orderingpub struct Relaxed;
/// The annotation type for acquire memory ordering, for the description of acquire memory/// ordering, see [module-level documentation].////// [module-level documentation]: crate::sync::atomic::orderingpub struct Acquire;
/// The annotation type for release memory ordering, for the description of release memory/// ordering, see [module-level documentation].////// [module-level documentation]: crate::sync::atomic::orderingpub struct Release;
/// The annotation type for fully-ordered memory ordering, for the description fully-ordered memory/// ordering, see [module-level documentation].////// [module-level documentation]: crate::sync::atomic::orderingpub struct Full;
/// Describes the exact memory ordering.#[doc(hidden)]pub enum OrderingType { /// Relaxed ordering. Relaxed, /// Acquire ordering. Acquire, /// Release ordering. Release, /// Fully-ordered. Full,}
mod internal { /// Sealed trait, can be only implemented inside atomic mod. pub trait Sealed {}
impl Sealed for super::Relaxed {} impl Sealed for super::Acquire {} impl Sealed for super::Release {} impl Sealed for super::Full {}}
/// The trait bound for annotating operations that support any ordering.pub trait Ordering: internal::Sealed { /// Describes the exact memory ordering. const TYPE: OrderingType;}
impl Ordering for Relaxed { const TYPE: OrderingType = OrderingType::Relaxed;}
impl Ordering for Acquire { const TYPE: OrderingType = OrderingType::Acquire;}
impl Ordering for Release { const TYPE: OrderingType = OrderingType::Release;}
impl Ordering for Full { const TYPE: OrderingType = OrderingType::Full;}
/// The trait bound for operations that only support acquire or relaxed ordering.pub trait AcquireOrRelaxed: Ordering {}
impl AcquireOrRelaxed for Acquire {}impl AcquireOrRelaxed for Relaxed {}
/// The trait bound for operations that only support release or relaxed ordering.pub trait ReleaseOrRelaxed: Ordering {}
impl ReleaseOrRelaxed for Release {}impl ReleaseOrRelaxed for Relaxed {}