// SPDX-License-Identifier: GPL-2.0//! Synchronisation primitives.//!//! This module contains the kernel APIs related to synchronisation that have been ported or//! wrapped for usage by Rust code in the kernel.use crate::prelude::*;use crate::types::Opaque;use pin_init;mod arc;pub mod completion;mod condvar;pub mod lock;mod locked_by;pub mod poll;pub mod rcu;pub use arc::{Arc, ArcBorrow, UniqueArc};pub use completion::Completion;pub use condvar::{new_condvar, CondVar, CondVarTimeoutResult};pub use lock::global::{global_lock, GlobalGuard, GlobalLock, GlobalLockBackend, GlobalLockedBy};pub use lock::mutex::{new_mutex, Mutex, MutexGuard};pub use lock::spinlock::{new_spinlock, SpinLock, SpinLockGuard};pub use locked_by::LockedBy;/// Represents a lockdep class. It's a wrapper around C's `lock_class_key`.#[repr(transparent)]#[pin_data(PinnedDrop)]pub struct LockClassKey { #[pin] inner: Opaque<bindings::lock_class_key>,}// SAFETY: `bindings::lock_class_key` is designed to be used concurrently from multiple threads and// provides its own synchronization.unsafe impl Sync for LockClassKey {}impl LockClassKey { /// Initializes a dynamically allocated lock class key. In the common case of using a /// statically allocated lock class key, the static_lock_class! macro should be used instead. /// /// # Example /// ``` /// # use kernel::c_str; /// # use kernel::alloc::KBox; /// # use kernel::types::ForeignOwnable; /// # use kernel::sync::{LockClassKey, SpinLock}; /// # use pin_init::stack_pin_init; /// /// let key = KBox::pin_init(LockClassKey::new_dynamic(), GFP_KERNEL)?; /// let key_ptr = key.into_foreign(); /// /// { /// stack_pin_init!(let num: SpinLock<u32> = SpinLock::new( /// 0, /// c_str!("my_spinlock"), /// // SAFETY: `key_ptr` is returned by the above `into_foreign()`, whose /// // `from_foreign()` has not yet been called. /// unsafe { <Pin<KBox<LockClassKey>> as ForeignOwnable>::borrow(key_ptr) } /// )); /// } /// /// // SAFETY: We dropped `num`, the only use of the key, so the result of the previous /// // `borrow` has also been dropped. Thus, it's safe to use from_foreign. /// unsafe { drop(<Pin<KBox<LockClassKey>> as ForeignOwnable>::from_foreign(key_ptr)) }; /// /// # Ok::<(), Error>(()) /// ``` pub fn new_dynamic() -> impl PinInit<Self> { pin_init!(Self { // SAFETY: lockdep_register_key expects an uninitialized block of memory inner <- Opaque::ffi_init(|slot| unsafe { bindings::lockdep_register_key(slot) }) }) } pub(crate) fn as_ptr(&self) -> *mut bindings::lock_class_key { self.inner.get() }}#[pinned_drop]impl PinnedDrop for LockClassKey { fn drop(self: Pin<&mut Self>) { // SAFETY: self.as_ptr was registered with lockdep and self is pinned, so the address // hasn't changed. Thus, it's safe to pass to unregister. unsafe { bindings::lockdep_unregister_key(self.as_ptr()) } }}/// Defines a new static lock class and returns a pointer to it.#[doc(hidden)]#[macro_export]macro_rules! static_lock_class { () => {{ static CLASS: $crate::sync::LockClassKey = // SAFETY: lockdep expects uninitialized memory when it's handed a statically allocated // lock_class_key unsafe { ::core::mem::MaybeUninit::uninit().assume_init() }; $crate::prelude::Pin::static_ref(&CLASS) }};}/// Returns the given string, if one is provided, otherwise generates one based on the source code/// location.#[doc(hidden)]#[macro_export]macro_rules! optional_name { () => { $crate::c_str!(::core::concat!(::core::file!(), ":", ::core::line!())) }; ($name:literal) => { $crate::c_str!($name) };}
// SPDX-License-Identifier: GPL-2.0
//! Synchronisation primitives.
//!
//! This module contains the kernel APIs related to synchronisation that have been ported or
//! wrapped for usage by Rust code in the kernel.
use crate::prelude::*;
use crate::types::Opaque;
use pin_init;
mod arc;
pub mod completion;
mod condvar;
pub mod lock;
mod locked_by;
pub mod poll;
pub mod rcu;
pub use arc::{Arc, ArcBorrow, UniqueArc};
pub use completion::Completion;
pub use condvar::{new_condvar, CondVar, CondVarTimeoutResult};
pub use lock::global::{global_lock, GlobalGuard, GlobalLock, GlobalLockBackend, GlobalLockedBy};
pub use lock::mutex::{new_mutex, Mutex, MutexGuard};
pub use lock::spinlock::{new_spinlock, SpinLock, SpinLockGuard};
pub use locked_by::LockedBy;
/// Represents a lockdep class. It's a wrapper around C's `lock_class_key`.
#[repr(transparent)]
#[pin_data(PinnedDrop)]
pub struct LockClassKey {
#[pin]
inner: Opaque<bindings::lock_class_key>,
}
// SAFETY: `bindings::lock_class_key` is designed to be used concurrently from multiple threads and
// provides its own synchronization.
unsafe impl Sync for LockClassKey {}
impl LockClassKey {
/// Initializes a dynamically allocated lock class key. In the common case of using a
/// statically allocated lock class key, the static_lock_class! macro should be used instead.
///
/// # Example
/// ```
/// # use kernel::c_str;
/// # use kernel::alloc::KBox;
/// # use kernel::types::ForeignOwnable;
/// # use kernel::sync::{LockClassKey, SpinLock};
/// # use pin_init::stack_pin_init;
///
/// let key = KBox::pin_init(LockClassKey::new_dynamic(), GFP_KERNEL)?;
/// let key_ptr = key.into_foreign();
///
/// {
/// stack_pin_init!(let num: SpinLock<u32> = SpinLock::new(
/// 0,
/// c_str!("my_spinlock"),
/// // SAFETY: `key_ptr` is returned by the above `into_foreign()`, whose
/// // `from_foreign()` has not yet been called.
/// unsafe { <Pin<KBox<LockClassKey>> as ForeignOwnable>::borrow(key_ptr) }
/// ));
/// }
///
/// // SAFETY: We dropped `num`, the only use of the key, so the result of the previous
/// // `borrow` has also been dropped. Thus, it's safe to use from_foreign.
/// unsafe { drop(<Pin<KBox<LockClassKey>> as ForeignOwnable>::from_foreign(key_ptr)) };
///
/// # Ok::<(), Error>(())
/// ```
pub fn new_dynamic() -> impl PinInit<Self> {
pin_init!(Self {
// SAFETY: lockdep_register_key expects an uninitialized block of memory
inner <- Opaque::ffi_init(|slot| unsafe { bindings::lockdep_register_key(slot) })
})
}
pub(crate) fn as_ptr(&self) -> *mut bindings::lock_class_key {
self.inner.get()
}
}
#[pinned_drop]
impl PinnedDrop for LockClassKey {
fn drop(self: Pin<&mut Self>) {
// SAFETY: self.as_ptr was registered with lockdep and self is pinned, so the address
// hasn't changed. Thus, it's safe to pass to unregister.
unsafe { bindings::lockdep_unregister_key(self.as_ptr()) }
}
}
/// Defines a new static lock class and returns a pointer to it.
#[doc(hidden)]
#[macro_export]
macro_rules! static_lock_class {
() => {{
static CLASS: $crate::sync::LockClassKey =
// SAFETY: lockdep expects uninitialized memory when it's handed a statically allocated
// lock_class_key
unsafe { ::core::mem::MaybeUninit::uninit().assume_init() };
$crate::prelude::Pin::static_ref(&CLASS)
}};
}
/// Returns the given string, if one is provided, otherwise generates one based on the source code
/// location.
#[doc(hidden)]
#[macro_export]
macro_rules! optional_name {
() => {
$crate::c_str!(::core::concat!(::core::file!(), ":", ::core::line!()))
};
($name:literal) => {
$crate::c_str!($name)
};
}