Covers the entire low-level locking API (lock, try_lock,
slow path, interruptible variants) and integration with
kernel bindings.
Signed-off-by: Onur Özkan <work@onurozkan.dev>
---
rust/kernel/sync/lock/ww_mutex.rs | 442 ++++++++++++++++++
rust/kernel/sync/lock/ww_mutex/acquire_ctx.rs | 172 +++++++
2 files changed, 614 insertions(+)
create mode 100644 rust/kernel/sync/lock/ww_mutex/acquire_ctx.rs
diff --git a/rust/kernel/sync/lock/ww_mutex.rs b/rust/kernel/sync/lock/ww_mutex.rs
index 727c51cc73af..00e25872a042 100644
--- a/rust/kernel/sync/lock/ww_mutex.rs
+++ b/rust/kernel/sync/lock/ww_mutex.rs
@@ -1,7 +1,449 @@
// SPDX-License-Identifier: GPL-2.0
//! Rust abstractions for the kernel's wound-wait locking primitives.
+//!
+//! It is designed to avoid deadlocks when locking multiple [`Mutex`]es
+//! that belong to the same [`Class`]. Each lock acquisition uses an
+//! [`AcquireCtx`] to track ordering and ensure forward progress.
+//!
+//! It is recommended to use [`LockSet`] as it provides safe high-level
+//! interface that automatically handles deadlocks, retries and context
+//! management.
+use crate::error::to_result;
+use crate::prelude::*;
+use crate::types::{NotThreadSafe, Opaque};
+use crate::{bindings, container_of};
+
+use core::cell::UnsafeCell;
+use core::marker::PhantomData;
+
+pub use acquire_ctx::AcquireCtx;
pub use class::Class;
+pub use lock_set::LockSet;
+mod acquire_ctx;
mod class;
+mod lock_set;
+
+/// A wound-wait (ww) mutex that is powered with deadlock avoidance
+/// when acquiring multiple locks of the same [`Class`].
+///
+/// Each mutex belongs to a [`Class`], which the wound-wait algorithm
+/// uses to figure out the order of acquisition and prevent deadlocks.
+///
+/// # Examples
+///
+/// ```
+/// use kernel::c_str;
+/// use kernel::sync::Arc;
+/// use kernel::sync::lock::ww_mutex::{AcquireCtx, Class, Mutex};
+/// use pin_init::stack_pin_init;
+///
+/// stack_pin_init!(let class = Class::new_wound_wait(c_str!("some_class")));
+/// let mutex = Arc::pin_init(Mutex::new(42, &class), GFP_KERNEL)?;
+///
+/// let ctx = KBox::pin_init(AcquireCtx::new(&class), GFP_KERNEL)?;
+///
+/// let guard = ctx.lock(&mutex)?;
+/// assert_eq!(*guard, 42);
+///
+/// # Ok::<(), Error>(())
+/// ```
+#[pin_data]
+#[repr(C)]
+pub struct Mutex<'a, T: ?Sized> {
+ _p: PhantomData<&'a Class>,
+ #[pin]
+ inner: Opaque<bindings::ww_mutex>,
+ data: UnsafeCell<T>,
+}
+
+// SAFETY: `Mutex` can be sent to another thread if the protected
+// data `T` can be.
+unsafe impl<T: ?Sized + Send> Send for Mutex<'_, T> {}
+
+// SAFETY: `Mutex` can be shared across threads if the protected
+// data `T` can be.
+unsafe impl<T: ?Sized + Send + Sync> Sync for Mutex<'_, T> {}
+
+impl<'class, T> Mutex<'class, T> {
+ /// Initializes [`Mutex`] with the given `data` and [`Class`].
+ pub fn new(data: T, class: &'class Class) -> impl PinInit<Self> {
+ let class_ptr = class.inner.get();
+ pin_init!(Mutex {
+ inner <- Opaque::ffi_init(|slot: *mut bindings::ww_mutex| {
+ // SAFETY: `class` is valid for the lifetime `'class` captured by `Self`.
+ unsafe { bindings::ww_mutex_init(slot, class_ptr) }
+ }),
+ data: UnsafeCell::new(data),
+ _p: PhantomData
+ })
+ }
+}
+
+impl<'class> Mutex<'class, ()> {
+ /// Creates a [`Mutex`] from a raw pointer.
+ ///
+ /// This function is intended for interoperability with C code.
+ ///
+ /// # Safety
+ ///
+ /// The caller must ensure that `ptr` is a valid pointer to a `ww_mutex`
+ /// and that it remains valid for the lifetime `'a`.
+ pub unsafe fn from_raw<'a>(ptr: *mut bindings::ww_mutex) -> &'a Self {
+ // SAFETY: By the safety contract, the caller guarantees that `ptr`
+ // points to a valid `ww_mutex` which is the `inner` field of `Mutex`
+ // and remains valid for the lifetime `'a`.
+ //
+ // Because [`Mutex`] is `#[repr(C)]`, the `inner` field sits at a
+ // stable offset that `container_of!` can safely rely on.
+ unsafe { &*container_of!(Opaque::cast_from(ptr), Self, inner) }
+ }
+}
+
+impl<'class, T: ?Sized> Mutex<'class, T> {
+ /// Checks if this [`Mutex`] is currently locked.
+ ///
+ /// The returned value is racy as another thread can acquire
+ /// or release the lock immediately after this call returns.
+ pub fn is_locked(&self) -> bool {
+ // SAFETY: It's safe to call `ww_mutex_is_locked` on
+ // a valid mutex.
+ unsafe { bindings::ww_mutex_is_locked(self.inner.get()) }
+ }
+
+ /// Locks this [`Mutex`] without [`AcquireCtx`].
+ pub fn lock(&self) -> Result<MutexGuard<'_, T>> {
+ lock_common(self, None, LockKind::Regular)
+ }
+
+ /// Similar to [`Self::lock`], but can be interrupted by signals.
+ pub fn lock_interruptible(&self) -> Result<MutexGuard<'_, T>> {
+ lock_common(self, None, LockKind::Interruptible)
+ }
+
+ /// Locks this [`Mutex`] without [`AcquireCtx`] using the slow path.
+ ///
+ /// This function should be used when [`Self::lock`] fails (typically due
+ /// to a potential deadlock).
+ pub fn lock_slow(&self) -> Result<MutexGuard<'_, T>> {
+ lock_common(self, None, LockKind::Slow)
+ }
+
+ /// Similar to [`Self::lock_slow`], but can be interrupted by signals.
+ pub fn lock_slow_interruptible(&self) -> Result<MutexGuard<'_, T>> {
+ lock_common(self, None, LockKind::SlowInterruptible)
+ }
+
+ /// Tries to lock this [`Mutex`] with no [`AcquireCtx`] and without blocking.
+ ///
+ /// Unlike [`Self::lock`], no deadlock handling is performed.
+ pub fn try_lock(&self) -> Result<MutexGuard<'_, T>> {
+ lock_common(self, None, LockKind::Try)
+ }
+}
+
+/// A guard that provides exclusive access to the data protected
+/// by a [`Mutex`].
+///
+/// # Invariants
+///
+/// The guard holds an exclusive lock on the associated [`Mutex`]. The lock is held
+/// for the entire lifetime of this guard and is automatically released when the
+/// guard is dropped.
+#[must_use = "the lock unlocks immediately when the guard is unused"]
+pub struct MutexGuard<'a, T: ?Sized> {
+ mutex: &'a Mutex<'a, T>,
+ _not_send: NotThreadSafe,
+}
+
+// SAFETY: `MutexGuard` can be shared between threads if the data can.
+unsafe impl<T: ?Sized + Sync> Sync for MutexGuard<'_, T> {}
+
+impl<'a, T: ?Sized> MutexGuard<'a, T> {
+ /// Creates a new guard for the given [`Mutex`].
+ fn new(mutex: &'a Mutex<'a, T>) -> Self {
+ Self {
+ mutex,
+ _not_send: NotThreadSafe,
+ }
+ }
+}
+
+impl<'a> MutexGuard<'a, ()> {
+ /// Creates a [`MutexGuard`] from a raw pointer.
+ ///
+ /// This function is intended for interoperability with C code.
+ ///
+ /// # Safety
+ ///
+ /// The caller must ensure that `ptr` is a valid pointer to a `ww_mutex`
+ /// and that it remains valid for the lifetime `'a`.
+ pub unsafe fn from_raw<'b>(ptr: *mut bindings::ww_mutex) -> MutexGuard<'b, ()> {
+ // SAFETY: By the safety contract, the caller guarantees that `ptr`
+ // points to a valid `ww_mutex` which is the `mutex` field of `Mutex`
+ // and remains valid for the lifetime `'a`.
+ let mutex = unsafe { Mutex::from_raw(ptr) };
+
+ MutexGuard::new(mutex)
+ }
+}
+
+impl<T: ?Sized> core::ops::Deref for MutexGuard<'_, T> {
+ type Target = T;
+
+ fn deref(&self) -> &Self::Target {
+ // SAFETY: We hold the lock, so we have exclusive access.
+ unsafe { &*self.mutex.data.get() }
+ }
+}
+
+impl<T: ?Sized + Unpin> core::ops::DerefMut for MutexGuard<'_, T> {
+ fn deref_mut(&mut self) -> &mut Self::Target {
+ // SAFETY: We hold the lock, so we have exclusive access.
+ unsafe { &mut *self.mutex.data.get() }
+ }
+}
+
+impl<T: ?Sized> Drop for MutexGuard<'_, T> {
+ fn drop(&mut self) {
+ // SAFETY: We hold the lock and are about to release it.
+ unsafe { bindings::ww_mutex_unlock(self.mutex.inner.get()) };
+ }
+}
+
+/// Locking kinds used by [`lock_common`] to unify the internal
+/// locking logic.
+///
+/// It's best not to expose this type (and [`lock_common`]) to the
+/// kernel, as it allows internal API changes without worrying
+/// about breaking external compatibility.
+#[derive(Copy, Clone, Debug)]
+enum LockKind {
+ /// Blocks until lock is acquired.
+ Regular,
+ /// Blocks but can be interrupted by signals.
+ Interruptible,
+ /// Used in slow path after deadlock detection.
+ Slow,
+ /// Slow path but interruptible.
+ SlowInterruptible,
+ /// Does not block, returns immediately if busy.
+ Try,
+}
+
+/// Internal helper that unifies the different locking kinds.
+///
+/// Returns [`EINVAL`] if the [`Mutex`] has a different [`Class`].
+fn lock_common<'a, T: ?Sized>(
+ mutex: &'a Mutex<'a, T>,
+ ctx: Option<&AcquireCtx<'_>>,
+ kind: LockKind,
+) -> Result<MutexGuard<'a, T>> {
+ let mutex_ptr = mutex.inner.get();
+
+ let ctx_ptr = match ctx {
+ Some(acquire_ctx) => {
+ let ctx_ptr = acquire_ctx.inner.get();
+
+ // SAFETY: `ctx_ptr` is a valid pointer for the entire
+ // lifetime of `ctx`.
+ let ctx_class = unsafe { (*ctx_ptr).ww_class };
+
+ // SAFETY: `mutex_ptr` is a valid pointer for the entire
+ // lifetime of `mutex`.
+ let mutex_class = unsafe { (*mutex_ptr).ww_class };
+
+ // `ctx` and `mutex` must use the same class.
+ if ctx_class != mutex_class {
+ return Err(EINVAL);
+ }
+
+ ctx_ptr
+ }
+ None => core::ptr::null_mut(),
+ };
+
+ match kind {
+ LockKind::Regular => {
+ // SAFETY: `Mutex` is always pinned. If `AcquireCtx` is `Some`, it is pinned,
+ // if `None`, it is set to `core::ptr::null_mut()`. Both cases are safe.
+ let ret = unsafe { bindings::ww_mutex_lock(mutex_ptr, ctx_ptr) };
+
+ to_result(ret)?;
+ }
+ LockKind::Interruptible => {
+ // SAFETY: `Mutex` is always pinned. If `AcquireCtx` is `Some`, it is pinned,
+ // if `None`, it is set to `core::ptr::null_mut()`. Both cases are safe.
+ let ret = unsafe { bindings::ww_mutex_lock_interruptible(mutex_ptr, ctx_ptr) };
+
+ to_result(ret)?;
+ }
+ LockKind::Slow => {
+ // SAFETY: `Mutex` is always pinned. If `AcquireCtx` is `Some`, it is pinned,
+ // if `None`, it is set to `core::ptr::null_mut()`. Both cases are safe.
+ unsafe { bindings::ww_mutex_lock_slow(mutex_ptr, ctx_ptr) };
+ }
+ LockKind::SlowInterruptible => {
+ // SAFETY: `Mutex` is always pinned. If `AcquireCtx` is `Some`, it is pinned,
+ // if `None`, it is set to `core::ptr::null_mut()`. Both cases are safe.
+ let ret = unsafe { bindings::ww_mutex_lock_slow_interruptible(mutex_ptr, ctx_ptr) };
+
+ to_result(ret)?;
+ }
+ LockKind::Try => {
+ // SAFETY: `Mutex` is always pinned. If `AcquireCtx` is `Some`, it is pinned,
+ // if `None`, it is set to `core::ptr::null_mut()`. Both cases are safe.
+ let ret = unsafe { bindings::ww_mutex_trylock(mutex_ptr, ctx_ptr) };
+
+ if ret == 0 {
+ return Err(EBUSY);
+ } else {
+ to_result(ret)?;
+ }
+ }
+ };
+
+ Ok(MutexGuard::new(mutex))
+}
+
+#[kunit_tests(rust_kernel_ww_mutex)]
+mod tests {
+ use crate::prelude::*;
+ use crate::sync::Arc;
+ use crate::{c_str, define_class};
+ use pin_init::stack_pin_init;
+
+ use super::*;
+
+ // A simple coverage on `define_class` macro.
+ define_class!(TEST_WOUND_WAIT_CLASS, wound_wait, c_str!("test"));
+ define_class!(TEST_WAIT_DIE_CLASS, wait_die, c_str!("test"));
+
+ #[test]
+ fn test_ww_mutex_basic_lock_unlock() -> Result {
+ stack_pin_init!(let class = Class::new_wound_wait(c_str!("test")));
+
+ let mutex = Arc::pin_init(Mutex::new(42, &class), GFP_KERNEL)?;
+
+ let ctx = KBox::pin_init(AcquireCtx::new(&class), GFP_KERNEL)?;
+
+ let guard = ctx.lock(&mutex)?;
+ assert_eq!(*guard, 42);
+
+ // Drop the lock.
+ drop(guard);
+
+ let mut guard = ctx.lock(&mutex)?;
+ *guard = 100;
+ assert_eq!(*guard, 100);
+
+ Ok(())
+ }
+
+ #[test]
+ fn test_ww_mutex_trylock() -> Result {
+ stack_pin_init!(let class = Class::new_wound_wait(c_str!("test")));
+
+ let mutex = Arc::pin_init(Mutex::new(123, &class), GFP_KERNEL)?;
+
+ let ctx = KBox::pin_init(AcquireCtx::new(&class), GFP_KERNEL)?;
+
+ // `try_lock` on unlocked mutex should succeed.
+ let guard = ctx.try_lock(&mutex)?;
+ assert_eq!(*guard, 123);
+
+ // Now it should fail immediately as it's already locked.
+ assert!(ctx.try_lock(&mutex).is_err());
+
+ Ok(())
+ }
+
+ #[test]
+ fn test_ww_mutex_is_locked() -> Result {
+ stack_pin_init!(let class = Class::new_wait_die(c_str!("test")));
+
+ let mutex = Arc::pin_init(Mutex::new("hello", &class), GFP_KERNEL)?;
+
+ let ctx = KBox::pin_init(AcquireCtx::new(&class), GFP_KERNEL)?;
+
+ // Should not be locked initially.
+ assert!(!mutex.is_locked());
+
+ let guard = ctx.lock(&mutex)?;
+ assert!(mutex.is_locked());
+
+ drop(guard);
+ assert!(!mutex.is_locked());
+
+ Ok(())
+ }
+
+ #[test]
+ fn test_ww_acquire_context_done() -> Result {
+ stack_pin_init!(let class = Class::new_wound_wait(c_str!("test")));
+
+ let mutex1 = Arc::pin_init(Mutex::new(1, &class), GFP_KERNEL)?;
+ let mutex2 = Arc::pin_init(Mutex::new(2, &class), GFP_KERNEL)?;
+
+ let ctx = KBox::pin_init(AcquireCtx::new(&class), GFP_KERNEL)?;
+
+ // Acquire multiple mutexes with the same context.
+ let guard1 = ctx.lock(&mutex1)?;
+ let guard2 = ctx.lock(&mutex2)?;
+
+ assert_eq!(*guard1, 1);
+ assert_eq!(*guard2, 2);
+
+ // SAFETY: It's called exactly once here and nowhere else.
+ unsafe { ctx.done() };
+
+ // We shouldn't be able to lock once it's `done`.
+ assert!(ctx.lock(&mutex1).is_err());
+ assert!(ctx.lock(&mutex2).is_err());
+
+ Ok(())
+ }
+
+ #[test]
+ fn test_with_global_classes() -> Result {
+ let mutex1 = Arc::pin_init(Mutex::new(100, &TEST_WOUND_WAIT_CLASS), GFP_KERNEL)?;
+ let mutex2 = Arc::pin_init(Mutex::new(200, &TEST_WAIT_DIE_CLASS), GFP_KERNEL)?;
+
+ let ww_ctx = KBox::pin_init(AcquireCtx::new(&TEST_WOUND_WAIT_CLASS), GFP_KERNEL)?;
+ let wd_ctx = KBox::pin_init(AcquireCtx::new(&TEST_WAIT_DIE_CLASS), GFP_KERNEL)?;
+
+ let ww_guard = ww_ctx.lock(&mutex1)?;
+ let wd_guard = wd_ctx.lock(&mutex2)?;
+
+ assert_eq!(*ww_guard, 100);
+ assert_eq!(*wd_guard, 200);
+
+ assert!(mutex1.is_locked());
+ assert!(mutex2.is_locked());
+
+ drop(ww_guard);
+ drop(wd_guard);
+
+ assert!(!mutex1.is_locked());
+ assert!(!mutex2.is_locked());
+
+ Ok(())
+ }
+
+ #[test]
+ fn test_mutex_without_ctx() -> Result {
+ let mutex = Arc::pin_init(Mutex::new(100, &TEST_WOUND_WAIT_CLASS), GFP_KERNEL)?;
+ let guard = mutex.lock()?;
+
+ assert_eq!(*guard, 100);
+ assert!(mutex.is_locked());
+
+ drop(guard);
+
+ assert!(!mutex.is_locked());
+
+ Ok(())
+ }
+}
diff --git a/rust/kernel/sync/lock/ww_mutex/acquire_ctx.rs b/rust/kernel/sync/lock/ww_mutex/acquire_ctx.rs
new file mode 100644
index 000000000000..141300e849eb
--- /dev/null
+++ b/rust/kernel/sync/lock/ww_mutex/acquire_ctx.rs
@@ -0,0 +1,172 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Provides [`AcquireCtx`] for managing multiple wound/wait
+//! mutexes from the same [`Class`].
+
+use crate::bindings;
+use crate::prelude::*;
+use crate::types::Opaque;
+
+use core::marker::PhantomData;
+
+use super::{lock_common, Class, LockKind, Mutex, MutexGuard};
+
+/// Groups multiple [`Mutex`]es for deadlock avoidance when acquired
+/// with the same [`Class`].
+///
+/// # Examples
+///
+/// ```
+/// use kernel::sync::lock::ww_mutex::{Class, AcquireCtx, Mutex};
+/// use kernel::c_str;
+/// use kernel::sync::Arc;
+/// use pin_init::stack_pin_init;
+///
+/// stack_pin_init!(let class = Class::new_wound_wait(c_str!("demo")));
+///
+/// // Create mutexes.
+/// let mutex1 = Arc::pin_init(Mutex::new(1, &class), GFP_KERNEL)?;
+/// let mutex2 = Arc::pin_init(Mutex::new(2, &class), GFP_KERNEL)?;
+///
+/// // Create acquire context for deadlock avoidance.
+/// let ctx = KBox::pin_init(AcquireCtx::new(&class), GFP_KERNEL)?;
+///
+/// let guard1 = ctx.lock(&mutex1)?;
+/// let guard2 = ctx.lock(&mutex2)?;
+///
+/// // Mark acquisition phase as complete.
+/// // SAFETY: It's called exactly once here and nowhere else.
+/// unsafe { ctx.done() };
+///
+/// # Ok::<(), Error>(())
+/// ```
+#[pin_data(PinnedDrop)]
+#[repr(transparent)]
+pub struct AcquireCtx<'a> {
+ #[pin]
+ pub(super) inner: Opaque<bindings::ww_acquire_ctx>,
+ _p: PhantomData<&'a Class>,
+}
+
+impl<'class> AcquireCtx<'class> {
+ /// Initializes a new [`AcquireCtx`] with the given [`Class`].
+ pub fn new(class: &'class Class) -> impl PinInit<Self> {
+ let class_ptr = class.inner.get();
+ pin_init!(AcquireCtx {
+ inner <- Opaque::ffi_init(|slot: *mut bindings::ww_acquire_ctx| {
+ // SAFETY: `class` is valid for the lifetime `'class` captured
+ // by `AcquireCtx`.
+ unsafe { bindings::ww_acquire_init(slot, class_ptr) }
+ }),
+ _p: PhantomData
+ })
+ }
+
+ /// Creates a [`AcquireCtx`] from a raw pointer.
+ ///
+ /// This function is intended for interoperability with C code.
+ ///
+ /// # Safety
+ ///
+ /// The caller must ensure that `ptr` is a valid pointer to the `inner` field
+ /// of [`AcquireCtx`] and that it remains valid for the lifetime `'a`.
+ pub unsafe fn from_raw<'a>(ptr: *mut bindings::ww_acquire_ctx) -> &'a Self {
+ // SAFETY: By the safety contract, `ptr` is valid to construct `AcquireCtx`.
+ unsafe { &*ptr.cast() }
+ }
+
+ /// Marks the end of the acquire phase.
+ ///
+ /// Calling this function is optional. It is just useful to document
+ /// the code and clearly designated the acquire phase from actually
+ /// using the locked data structures.
+ ///
+ /// After calling this function, no more mutexes can be acquired with
+ /// this context.
+ ///
+ /// # Safety
+ ///
+ /// The caller must ensure that this function is called only once
+ /// and after calling it, no further mutexes are acquired using
+ /// this context.
+ pub unsafe fn done(&self) {
+ // SAFETY: By the safety contract, the caller guarantees that this
+ // function is called only once.
+ unsafe { bindings::ww_acquire_done(self.inner.get()) };
+ }
+
+ /// Re-initializes the [`AcquireCtx`].
+ ///
+ /// Must be called after releasing all locks when [`EDEADLK`] occurs.
+ ///
+ /// # Safety
+ ///
+ /// The caller must ensure no locks are held in this [`AcquireCtx`].
+ pub unsafe fn reinit(self: Pin<&mut Self>) {
+ let ctx = self.inner.get();
+
+ // SAFETY: `ww_class` is always a valid pointer in properly initialized
+ // `AcquireCtx`.
+ let class_ptr = unsafe { (*ctx).ww_class };
+
+ // SAFETY:
+ // - Lifetime of any guard (which hold an immutable borrow of `self`) cannot overlap
+ // with the execution of this function. This enforces that all locks acquired via
+ // this context have been released.
+ //
+ // - `ctx` is guaranteed to be initialized because `ww_acquire_fini`
+ // can only be called from the `Drop` implementation.
+ //
+ // - `ww_acquire_fini` is safe to call on an initialized context.
+ unsafe { bindings::ww_acquire_fini(ctx) };
+
+ // SAFETY: `ww_acquire_init` is safe to call with valid pointers
+ // to initialize an uninitialized context.
+ unsafe { bindings::ww_acquire_init(ctx, class_ptr) };
+ }
+
+ /// Locks the given [`Mutex`] on this [`AcquireCtx`].
+ pub fn lock<'a, T>(&'a self, mutex: &'a Mutex<'a, T>) -> Result<MutexGuard<'a, T>> {
+ lock_common(mutex, Some(self), LockKind::Regular)
+ }
+
+ /// Similar to [`Self::lock`], but can be interrupted by signals.
+ pub fn lock_interruptible<'a, T>(
+ &'a self,
+ mutex: &'a Mutex<'a, T>,
+ ) -> Result<MutexGuard<'a, T>> {
+ lock_common(mutex, Some(self), LockKind::Interruptible)
+ }
+
+ /// Locks the given [`Mutex`] on this [`AcquireCtx`] using the slow path.
+ ///
+ /// This function should be used when [`Self::lock`] fails (typically due
+ /// to a potential deadlock).
+ pub fn lock_slow<'a, T>(&'a self, mutex: &'a Mutex<'a, T>) -> Result<MutexGuard<'a, T>> {
+ lock_common(mutex, Some(self), LockKind::Slow)
+ }
+
+ /// Similar to [`Self::lock_slow`], but can be interrupted by signals.
+ pub fn lock_slow_interruptible<'a, T>(
+ &'a self,
+ mutex: &'a Mutex<'a, T>,
+ ) -> Result<MutexGuard<'a, T>> {
+ lock_common(mutex, Some(self), LockKind::SlowInterruptible)
+ }
+
+ /// Tries to lock the [`Mutex`] on this [`AcquireCtx`] without blocking.
+ ///
+ /// Unlike [`Self::lock`], no deadlock handling is performed.
+ pub fn try_lock<'a, T>(&'a self, mutex: &'a Mutex<'a, T>) -> Result<MutexGuard<'a, T>> {
+ lock_common(mutex, Some(self), LockKind::Try)
+ }
+}
+
+#[pinned_drop]
+impl PinnedDrop for AcquireCtx<'_> {
+ fn drop(self: Pin<&mut Self>) {
+ // SAFETY: Given the lifetime bounds we know no locks are held,
+ // so calling `ww_acquire_fini` is safe.
+ unsafe { bindings::ww_acquire_fini(self.inner.get()) };
+ }
+}
--
2.51.2
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