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19096bce81
This is the traditional condition variable or monitor synchronisation primitive. It is implemented with C's `wait_queue_head_t`. It allows users to release a lock and go to sleep while guaranteeing that notifications won't be missed. This is achieved by enqueuing a wait entry before releasing the lock. Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Will Deacon <will@kernel.org> Cc: Waiman Long <longman@redhat.com> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20230411054543.21278-12-wedsonaf@gmail.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
60 lines
1.6 KiB
Rust
60 lines
1.6 KiB
Rust
// SPDX-License-Identifier: GPL-2.0
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//! Synchronisation primitives.
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//!
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//! This module contains the kernel APIs related to synchronisation that have been ported or
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//! wrapped for usage by Rust code in the kernel.
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use crate::types::Opaque;
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mod arc;
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mod condvar;
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pub mod lock;
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mod locked_by;
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pub use arc::{Arc, ArcBorrow, UniqueArc};
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pub use condvar::CondVar;
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pub use lock::{mutex::Mutex, spinlock::SpinLock};
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pub use locked_by::LockedBy;
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/// Represents a lockdep class. It's a wrapper around C's `lock_class_key`.
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#[repr(transparent)]
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pub struct LockClassKey(Opaque<bindings::lock_class_key>);
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// SAFETY: `bindings::lock_class_key` is designed to be used concurrently from multiple threads and
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// provides its own synchronization.
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unsafe impl Sync for LockClassKey {}
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impl LockClassKey {
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/// Creates a new lock class key.
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pub const fn new() -> Self {
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Self(Opaque::uninit())
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}
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pub(crate) fn as_ptr(&self) -> *mut bindings::lock_class_key {
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self.0.get()
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}
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}
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/// Defines a new static lock class and returns a pointer to it.
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#[doc(hidden)]
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#[macro_export]
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macro_rules! static_lock_class {
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() => {{
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static CLASS: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
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&CLASS
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}};
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}
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/// Returns the given string, if one is provided, otherwise generates one based on the source code
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/// location.
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#[doc(hidden)]
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#[macro_export]
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macro_rules! optional_name {
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() => {
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$crate::c_str!(::core::concat!(::core::file!(), ":", ::core::line!()))
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};
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($name:literal) => {
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$crate::c_str!($name)
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};
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}
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