Use the term "lock" for `Mutex`/`RwLock` instead of "mutex" 2022-03-debug-rwlock
authorMatt Corallo <git@bluematt.me>
Wed, 9 Mar 2022 19:10:59 +0000 (19:10 +0000)
committerMatt Corallo <git@bluematt.me>
Fri, 18 Mar 2022 18:54:27 +0000 (18:54 +0000)
lightning/src/debug_sync.rs

index 04fc86bbbc758fa54366ef3217103d901fe0d84c..b31ceacea15852def4203b037d8e36216094f5c4 100644 (file)
@@ -43,43 +43,43 @@ impl Condvar {
 }
 
 thread_local! {
-       /// We track the set of locks currently held by a reference to their `MutexMetadata`
-       static MUTEXES_HELD: RefCell<HashSet<Arc<MutexMetadata>>> = RefCell::new(HashSet::new());
+       /// We track the set of locks currently held by a reference to their `LockMetadata`
+       static LOCKS_HELD: RefCell<HashSet<Arc<LockMetadata>>> = RefCell::new(HashSet::new());
 }
-static MUTEX_IDX: AtomicUsize = AtomicUsize::new(0);
+static LOCK_IDX: AtomicUsize = AtomicUsize::new(0);
 
-/// Metadata about a single mutex, by id, the set of things locked-before it, and the backtrace of
+/// Metadata about a single lock, by id, the set of things locked-before it, and the backtrace of
 /// when the Mutex itself was constructed.
-struct MutexMetadata {
-       mutex_idx: u64,
-       locked_before: StdMutex<HashSet<Arc<MutexMetadata>>>,
+struct LockMetadata {
+       lock_idx: u64,
+       locked_before: StdMutex<HashSet<Arc<LockMetadata>>>,
        #[cfg(feature = "backtrace")]
-       mutex_construction_bt: Backtrace,
+       lock_construction_bt: Backtrace,
 }
-impl PartialEq for MutexMetadata {
-       fn eq(&self, o: &MutexMetadata) -> bool { self.mutex_idx == o.mutex_idx }
+impl PartialEq for LockMetadata {
+       fn eq(&self, o: &LockMetadata) -> bool { self.lock_idx == o.lock_idx }
 }
-impl Eq for MutexMetadata {}
-impl std::hash::Hash for MutexMetadata {
-       fn hash<H: std::hash::Hasher>(&self, hasher: &mut H) { hasher.write_u64(self.mutex_idx); }
+impl Eq for LockMetadata {}
+impl std::hash::Hash for LockMetadata {
+       fn hash<H: std::hash::Hasher>(&self, hasher: &mut H) { hasher.write_u64(self.lock_idx); }
 }
 
-impl MutexMetadata {
-       fn new() -> MutexMetadata {
-               MutexMetadata {
+impl LockMetadata {
+       fn new() -> LockMetadata {
+               LockMetadata {
                        locked_before: StdMutex::new(HashSet::new()),
-                       mutex_idx: MUTEX_IDX.fetch_add(1, Ordering::Relaxed) as u64,
+                       lock_idx: LOCK_IDX.fetch_add(1, Ordering::Relaxed) as u64,
                        #[cfg(feature = "backtrace")]
-                       mutex_construction_bt: Backtrace::new(),
+                       lock_construction_bt: Backtrace::new(),
                }
        }
 
        // Returns whether we were a recursive lock (only relevant for read)
-       fn _pre_lock(this: &Arc<MutexMetadata>, read: bool) -> bool {
+       fn _pre_lock(this: &Arc<LockMetadata>, read: bool) -> bool {
                let mut inserted = false;
-               MUTEXES_HELD.with(|held| {
-                       // For each mutex which is currently locked, check that no mutex's locked-before
-                       // set includes the mutex we're about to lock, which would imply a lockorder
+               LOCKS_HELD.with(|held| {
+                       // For each lock which is currently locked, check that no lock's locked-before
+                       // set includes the lock we're about to lock, which would imply a lockorder
                        // inversion.
                        for locked in held.borrow().iter() {
                                if read && *locked == *this {
@@ -89,17 +89,17 @@ impl MutexMetadata {
                        }
                        for locked in held.borrow().iter() {
                                if !read && *locked == *this {
-                                       panic!("Tried to lock a mutex while it was held!");
+                                       panic!("Tried to lock a lock while it was held!");
                                }
                                for locked_dep in locked.locked_before.lock().unwrap().iter() {
                                        if *locked_dep == *this {
                                                #[cfg(feature = "backtrace")]
-                                               panic!("Tried to violate existing lockorder.\nMutex that should be locked after the current lock was created at the following backtrace.\nNote that to get a backtrace for the lockorder violation, you should set RUST_BACKTRACE=1\n{:?}", locked.mutex_construction_bt);
+                                               panic!("Tried to violate existing lockorder.\nMutex that should be locked after the current lock was created at the following backtrace.\nNote that to get a backtrace for the lockorder violation, you should set RUST_BACKTRACE=1\n{:?}", locked.lock_construction_bt);
                                                #[cfg(not(feature = "backtrace"))]
                                                panic!("Tried to violate existing lockorder. Build with the backtrace feature for more info.");
                                        }
                                }
-                               // Insert any already-held mutexes in our locked-before set.
+                               // Insert any already-held locks in our locked-before set.
                                this.locked_before.lock().unwrap().insert(Arc::clone(locked));
                        }
                        held.borrow_mut().insert(Arc::clone(this));
@@ -108,11 +108,11 @@ impl MutexMetadata {
                inserted
        }
 
-       fn pre_lock(this: &Arc<MutexMetadata>) { Self::_pre_lock(this, false); }
-       fn pre_read_lock(this: &Arc<MutexMetadata>) -> bool { Self::_pre_lock(this, true) }
+       fn pre_lock(this: &Arc<LockMetadata>) { Self::_pre_lock(this, false); }
+       fn pre_read_lock(this: &Arc<LockMetadata>) -> bool { Self::_pre_lock(this, true) }
 
-       fn try_locked(this: &Arc<MutexMetadata>) {
-               MUTEXES_HELD.with(|held| {
+       fn try_locked(this: &Arc<LockMetadata>) {
+               LOCKS_HELD.with(|held| {
                        // Since a try-lock will simply fail if the lock is held already, we do not
                        // consider try-locks to ever generate lockorder inversions. However, if a try-lock
                        // succeeds, we do consider it to have created lockorder dependencies.
@@ -126,7 +126,7 @@ impl MutexMetadata {
 
 pub struct Mutex<T: Sized> {
        inner: StdMutex<T>,
-       deps: Arc<MutexMetadata>,
+       deps: Arc<LockMetadata>,
 }
 
 #[must_use = "if unused the Mutex will immediately unlock"]
@@ -148,7 +148,7 @@ impl<'a, T: Sized> MutexGuard<'a, T> {
 
 impl<T: Sized> Drop for MutexGuard<'_, T> {
        fn drop(&mut self) {
-               MUTEXES_HELD.with(|held| {
+               LOCKS_HELD.with(|held| {
                        held.borrow_mut().remove(&self.mutex.deps);
                });
        }
@@ -170,18 +170,18 @@ impl<T: Sized> DerefMut for MutexGuard<'_, T> {
 
 impl<T> Mutex<T> {
        pub fn new(inner: T) -> Mutex<T> {
-               Mutex { inner: StdMutex::new(inner), deps: Arc::new(MutexMetadata::new()) }
+               Mutex { inner: StdMutex::new(inner), deps: Arc::new(LockMetadata::new()) }
        }
 
        pub fn lock<'a>(&'a self) -> LockResult<MutexGuard<'a, T>> {
-               MutexMetadata::pre_lock(&self.deps);
+               LockMetadata::pre_lock(&self.deps);
                self.inner.lock().map(|lock| MutexGuard { mutex: self, lock }).map_err(|_| ())
        }
 
        pub fn try_lock<'a>(&'a self) -> LockResult<MutexGuard<'a, T>> {
                let res = self.inner.try_lock().map(|lock| MutexGuard { mutex: self, lock }).map_err(|_| ());
                if res.is_ok() {
-                       MutexMetadata::try_locked(&self.deps);
+                       LockMetadata::try_locked(&self.deps);
                }
                res
        }
@@ -189,25 +189,25 @@ impl<T> Mutex<T> {
 
 pub struct RwLock<T: Sized> {
        inner: StdRwLock<T>,
-       deps: Arc<MutexMetadata>,
+       deps: Arc<LockMetadata>,
 }
 
 pub struct RwLockReadGuard<'a, T: Sized + 'a> {
-       mutex: &'a RwLock<T>,
+       lock: &'a RwLock<T>,
        first_lock: bool,
-       lock: StdRwLockReadGuard<'a, T>,
+       guard: StdRwLockReadGuard<'a, T>,
 }
 
 pub struct RwLockWriteGuard<'a, T: Sized + 'a> {
-       mutex: &'a RwLock<T>,
-       lock: StdRwLockWriteGuard<'a, T>,
+       lock: &'a RwLock<T>,
+       guard: StdRwLockWriteGuard<'a, T>,
 }
 
 impl<T: Sized> Deref for RwLockReadGuard<'_, T> {
        type Target = T;
 
        fn deref(&self) -> &T {
-               &self.lock.deref()
+               &self.guard.deref()
        }
 }
 
@@ -219,8 +219,8 @@ impl<T: Sized> Drop for RwLockReadGuard<'_, T> {
                        // always be true.
                        return;
                }
-               MUTEXES_HELD.with(|held| {
-                       held.borrow_mut().remove(&self.mutex.deps);
+               LOCKS_HELD.with(|held| {
+                       held.borrow_mut().remove(&self.lock.deps);
                });
        }
 }
@@ -229,43 +229,43 @@ impl<T: Sized> Deref for RwLockWriteGuard<'_, T> {
        type Target = T;
 
        fn deref(&self) -> &T {
-               &self.lock.deref()
+               &self.guard.deref()
        }
 }
 
 impl<T: Sized> Drop for RwLockWriteGuard<'_, T> {
        fn drop(&mut self) {
-               MUTEXES_HELD.with(|held| {
-                       held.borrow_mut().remove(&self.mutex.deps);
+               LOCKS_HELD.with(|held| {
+                       held.borrow_mut().remove(&self.lock.deps);
                });
        }
 }
 
 impl<T: Sized> DerefMut for RwLockWriteGuard<'_, T> {
        fn deref_mut(&mut self) -> &mut T {
-               self.lock.deref_mut()
+               self.guard.deref_mut()
        }
 }
 
 impl<T> RwLock<T> {
        pub fn new(inner: T) -> RwLock<T> {
-               RwLock { inner: StdRwLock::new(inner), deps: Arc::new(MutexMetadata::new()) }
+               RwLock { inner: StdRwLock::new(inner), deps: Arc::new(LockMetadata::new()) }
        }
 
        pub fn read<'a>(&'a self) -> LockResult<RwLockReadGuard<'a, T>> {
-               let first_lock = MutexMetadata::pre_read_lock(&self.deps);
-               self.inner.read().map(|lock| RwLockReadGuard { mutex: self, lock, first_lock }).map_err(|_| ())
+               let first_lock = LockMetadata::pre_read_lock(&self.deps);
+               self.inner.read().map(|guard| RwLockReadGuard { lock: self, guard, first_lock }).map_err(|_| ())
        }
 
        pub fn write<'a>(&'a self) -> LockResult<RwLockWriteGuard<'a, T>> {
-               MutexMetadata::pre_lock(&self.deps);
-               self.inner.write().map(|lock| RwLockWriteGuard { mutex: self, lock }).map_err(|_| ())
+               LockMetadata::pre_lock(&self.deps);
+               self.inner.write().map(|guard| RwLockWriteGuard { lock: self, guard }).map_err(|_| ())
        }
 
        pub fn try_write<'a>(&'a self) -> LockResult<RwLockWriteGuard<'a, T>> {
-               let res = self.inner.try_write().map(|lock| RwLockWriteGuard { mutex: self, lock }).map_err(|_| ());
+               let res = self.inner.try_write().map(|guard| RwLockWriteGuard { lock: self, guard }).map_err(|_| ());
                if res.is_ok() {
-                       MutexMetadata::try_locked(&self.deps);
+                       LockMetadata::try_locked(&self.deps);
                }
                res
        }