diff options
Diffstat (limited to 'library/std/src/sys_common')
| -rw-r--r-- | library/std/src/sys_common/remutex.rs | 46 | ||||
| -rw-r--r-- | library/std/src/sys_common/remutex/tests.rs | 37 |
2 files changed, 22 insertions, 61 deletions
diff --git a/library/std/src/sys_common/remutex.rs b/library/std/src/sys_common/remutex.rs index 8921af311d4..b448ae3a997 100644 --- a/library/std/src/sys_common/remutex.rs +++ b/library/std/src/sys_common/remutex.rs @@ -1,13 +1,11 @@ #[cfg(all(test, not(target_os = "emscripten")))] mod tests; +use super::mutex as sys; use crate::cell::UnsafeCell; -use crate::marker::PhantomPinned; use crate::ops::Deref; use crate::panic::{RefUnwindSafe, UnwindSafe}; -use crate::pin::Pin; use crate::sync::atomic::{AtomicUsize, Ordering::Relaxed}; -use crate::sys::locks as sys; /// A re-entrant mutual exclusion /// @@ -41,11 +39,10 @@ use crate::sys::locks as sys; /// synchronization is left to the mutex, making relaxed memory ordering for /// the `owner` field fine in all cases. pub struct ReentrantMutex<T> { - mutex: sys::Mutex, + mutex: sys::MovableMutex, owner: AtomicUsize, lock_count: UnsafeCell<u32>, data: T, - _pinned: PhantomPinned, } unsafe impl<T: Send> Send for ReentrantMutex<T> {} @@ -68,39 +65,22 @@ impl<T> RefUnwindSafe for ReentrantMutex<T> {} /// guarded data. #[must_use = "if unused the ReentrantMutex will immediately unlock"] pub struct ReentrantMutexGuard<'a, T: 'a> { - lock: Pin<&'a ReentrantMutex<T>>, + lock: &'a ReentrantMutex<T>, } impl<T> !Send for ReentrantMutexGuard<'_, T> {} impl<T> ReentrantMutex<T> { /// Creates a new reentrant mutex in an unlocked state. - /// - /// # Unsafety - /// - /// This function is unsafe because it is required that `init` is called - /// once this mutex is in its final resting place, and only then are the - /// lock/unlock methods safe. - pub const unsafe fn new(t: T) -> ReentrantMutex<T> { + pub const fn new(t: T) -> ReentrantMutex<T> { ReentrantMutex { - mutex: sys::Mutex::new(), + mutex: sys::MovableMutex::new(), owner: AtomicUsize::new(0), lock_count: UnsafeCell::new(0), data: t, - _pinned: PhantomPinned, } } - /// Initializes this mutex so it's ready for use. - /// - /// # Unsafety - /// - /// Unsafe to call more than once, and must be called after this will no - /// longer move in memory. - pub unsafe fn init(self: Pin<&mut Self>) { - self.get_unchecked_mut().mutex.init() - } - /// Acquires a mutex, blocking the current thread until it is able to do so. /// /// This function will block the caller until it is available to acquire the mutex. @@ -113,15 +93,14 @@ impl<T> ReentrantMutex<T> { /// If another user of this mutex panicked while holding the mutex, then /// this call will return failure if the mutex would otherwise be /// acquired. - pub fn lock(self: Pin<&Self>) -> ReentrantMutexGuard<'_, T> { + pub fn lock(&self) -> ReentrantMutexGuard<'_, T> { let this_thread = current_thread_unique_ptr(); - // Safety: We only touch lock_count when we own the lock, - // and since self is pinned we can safely call the lock() on the mutex. + // Safety: We only touch lock_count when we own the lock. unsafe { if self.owner.load(Relaxed) == this_thread { self.increment_lock_count(); } else { - self.mutex.lock(); + self.mutex.raw_lock(); self.owner.store(this_thread, Relaxed); debug_assert_eq!(*self.lock_count.get(), 0); *self.lock_count.get() = 1; @@ -142,10 +121,9 @@ impl<T> ReentrantMutex<T> { /// If another user of this mutex panicked while holding the mutex, then /// this call will return failure if the mutex would otherwise be /// acquired. - pub fn try_lock(self: Pin<&Self>) -> Option<ReentrantMutexGuard<'_, T>> { + pub fn try_lock(&self) -> Option<ReentrantMutexGuard<'_, T>> { let this_thread = current_thread_unique_ptr(); - // Safety: We only touch lock_count when we own the lock, - // and since self is pinned we can safely call the try_lock on the mutex. + // Safety: We only touch lock_count when we own the lock. unsafe { if self.owner.load(Relaxed) == this_thread { self.increment_lock_count(); @@ -179,12 +157,12 @@ impl<T> Deref for ReentrantMutexGuard<'_, T> { impl<T> Drop for ReentrantMutexGuard<'_, T> { #[inline] fn drop(&mut self) { - // Safety: We own the lock, and the lock is pinned. + // Safety: We own the lock. unsafe { *self.lock.lock_count.get() -= 1; if *self.lock.lock_count.get() == 0 { self.lock.owner.store(0, Relaxed); - self.lock.mutex.unlock(); + self.lock.mutex.raw_unlock(); } } } diff --git a/library/std/src/sys_common/remutex/tests.rs b/library/std/src/sys_common/remutex/tests.rs index 64873b850d3..8e97ce11c34 100644 --- a/library/std/src/sys_common/remutex/tests.rs +++ b/library/std/src/sys_common/remutex/tests.rs @@ -1,18 +1,11 @@ -use crate::boxed::Box; use crate::cell::RefCell; -use crate::pin::Pin; use crate::sync::Arc; use crate::sys_common::remutex::{ReentrantMutex, ReentrantMutexGuard}; use crate::thread; #[test] fn smoke() { - let m = unsafe { - let mut m = Box::pin(ReentrantMutex::new(())); - m.as_mut().init(); - m - }; - let m = m.as_ref(); + let m = ReentrantMutex::new(()); { let a = m.lock(); { @@ -29,20 +22,15 @@ fn smoke() { #[test] fn is_mutex() { - let m = unsafe { - // FIXME: Simplify this if Arc gets an Arc::get_pin_mut. - let mut m = Arc::new(ReentrantMutex::new(RefCell::new(0))); - Pin::new_unchecked(Arc::get_mut_unchecked(&mut m)).init(); - Pin::new_unchecked(m) - }; + let m = Arc::new(ReentrantMutex::new(RefCell::new(0))); let m2 = m.clone(); - let lock = m.as_ref().lock(); + let lock = m.lock(); let child = thread::spawn(move || { - let lock = m2.as_ref().lock(); + let lock = m2.lock(); assert_eq!(*lock.borrow(), 4950); }); for i in 0..100 { - let lock = m.as_ref().lock(); + let lock = m.lock(); *lock.borrow_mut() += i; } drop(lock); @@ -51,22 +39,17 @@ fn is_mutex() { #[test] fn trylock_works() { - let m = unsafe { - // FIXME: Simplify this if Arc gets an Arc::get_pin_mut. - let mut m = Arc::new(ReentrantMutex::new(())); - Pin::new_unchecked(Arc::get_mut_unchecked(&mut m)).init(); - Pin::new_unchecked(m) - }; + let m = Arc::new(ReentrantMutex::new(())); let m2 = m.clone(); - let _lock = m.as_ref().try_lock(); - let _lock2 = m.as_ref().try_lock(); + let _lock = m.try_lock(); + let _lock2 = m.try_lock(); thread::spawn(move || { - let lock = m2.as_ref().try_lock(); + let lock = m2.try_lock(); assert!(lock.is_none()); }) .join() .unwrap(); - let _lock3 = m.as_ref().try_lock(); + let _lock3 = m.try_lock(); } pub struct Answer<'a>(pub ReentrantMutexGuard<'a, RefCell<u32>>); |