Kernel/Mutex: Propagate thread priority changes to other threads inheriting the priority via mutexes

1 files changed, 22 insertions, 38 deletions

diff --git a/src/core/hle/kernel/mutex.cpp b/src/core/hle/kernel/mutex.cpp
index 84ff65150..cef961289 100644
--- a/src/core/hle/kernel/mutex.cpp
+++ b/src/core/hle/kernel/mutex.cpp
@@ -13,38 +13,6 @@
 
 namespace Kernel {
 
-/**
- * Boost's a thread's priority to the best priority among the thread's held mutexes.
- * This prevents priority inversion via priority inheritance.
- */
-static void UpdateThreadPriority(Thread* thread) {
-    s32 best_priority = THREADPRIO_LOWEST;
-    for (auto& mutex : thread->held_mutexes) {
-        if (mutex->priority < best_priority)
-            best_priority = mutex->priority;
-    }
-
-    best_priority = std::min(best_priority, thread->nominal_priority);
-    thread->SetPriority(best_priority);
-}
-
-/**
- * Elevate the mutex priority to the best priority
- * among the priorities of all its waiting threads.
- */
-static void UpdateMutexPriority(Mutex* mutex) {
-    s32 best_priority = THREADPRIO_LOWEST;
-    for (auto& waiter : mutex->GetWaitingThreads()) {
-        if (waiter->current_priority < best_priority)
-            best_priority = waiter->current_priority;
-    }
-
-    if (best_priority != mutex->priority) {
-        mutex->priority = best_priority;
-        UpdateThreadPriority(mutex->holding_thread.get());
-    }
-}
-
 void ReleaseThreadMutexes(Thread* thread) {
     for (auto& mtx : thread->held_mutexes) {
         mtx->lock_count = 0;
@@ -83,9 +51,7 @@ void Mutex::Acquire(Thread* thread) {
         priority = thread->current_priority;
         thread->held_mutexes.insert(this);
         holding_thread = thread;
-
-        UpdateThreadPriority(thread);
-
+        thread->UpdatePriority();
         Core::System::GetInstance().PrepareReschedule();
     }
 
@@ -100,7 +66,7 @@ void Mutex::Release() {
         // Yield to the next thread only if we've fully released the mutex
         if (lock_count == 0) {
             holding_thread->held_mutexes.erase(this);
-            UpdateThreadPriority(holding_thread.get());
+            holding_thread->UpdatePriority();
             holding_thread = nullptr;
             WakeupAllWaitingThreads();
             Core::System::GetInstance().PrepareReschedule();
@@ -110,12 +76,30 @@ void Mutex::Release() {
 
 void Mutex::AddWaitingThread(SharedPtr<Thread> thread) {
     WaitObject::AddWaitingThread(thread);
-    UpdateMutexPriority(this);
+    thread->pending_mutexes.insert(this);
+    UpdatePriority();
 }
 
 void Mutex::RemoveWaitingThread(Thread* thread) {
     WaitObject::RemoveWaitingThread(thread);
-    UpdateMutexPriority(this);
+    thread->pending_mutexes.erase(this);
+    UpdatePriority();
+}
+
+void Mutex::UpdatePriority() {
+    if (!holding_thread)
+        return;
+
+    s32 best_priority = THREADPRIO_LOWEST;
+    for (auto& waiter : GetWaitingThreads()) {
+        if (waiter->current_priority < best_priority)
+            best_priority = waiter->current_priority;
+    }
+
+    if (best_priority != priority) {
+        priority = best_priority;
+        holding_thread->UpdatePriority();
+    }
 }
 
 } // namespace