commit 39e9a251773fd94b48bfe1c3120ef95c7e8b673a
author TreeHugger Robot <treehugger-gerrit@google.com> Tue Feb 18 16:40:23 2020 +0000
committer Android (Google) Code Review <android-gerrit@google.com> Tue Feb 18 16:40:23 2020 +0000
tree ba690cee0694d8a74e15821277f1976bf48387b3
parent 31cf0a0d5a9c722e1a86f57963e5e8dd0e1bef76
parent e4943eb672d8861d700affa2e3f3306e73a1648d

Merge "BLASTBufferQueue: Correct deadlocks in mNextTransaction handling."

libs/gui/BLASTBufferQueue.cpp

diff --git a/libs/gui/BLASTBufferQueue.cpp b/libs/gui/BLASTBufferQueue.cpp
index 02416e4..acd833f 100644
--- a/libs/gui/BLASTBufferQueue.cpp
+++ b/libs/gui/BLASTBufferQueue.cpp
@@ -180,9 +180,9 @@
     }
     mPendingReleaseItem.item = std::move(mSubmitted.front());
     mSubmitted.pop();
-    if (mNextTransaction == nullptr) {
-        processNextBufferLocked();
-    }
+
+    processNextBufferLocked();
+
     mCallbackCV.notify_all();
     decStrong((void*)transactionCallbackThunk);
 }
@@ -201,7 +201,7 @@
     SurfaceComposerClient::Transaction localTransaction;
     bool applyTransaction = true;
     SurfaceComposerClient::Transaction* t = &localTransaction;
-    if (mNextTransaction != nullptr) {
+    if (mNextTransaction != nullptr && mUseNextTransaction) {
         t = mNextTransaction;
         mNextTransaction = nullptr;
         applyTransaction = false;
@@ -263,9 +263,10 @@
     std::unique_lock _lock{mMutex};
 
     if (mNextTransaction != nullptr) {
-        while (mNumFrameAvailable > 0 || mNumAcquired == MAX_ACQUIRED_BUFFERS) {
+        while (mNumFrameAvailable > 0 || mNumAcquired == MAX_ACQUIRED_BUFFERS + 1) {
             mCallbackCV.wait(_lock);
         }
+        mUseNextTransaction = true;
     }
     // add to shadow queue
     mNumFrameAvailable++;
@@ -274,6 +275,7 @@
 
 void BLASTBufferQueue::setNextTransaction(SurfaceComposerClient::Transaction* t) {
     std::lock_guard _lock{mMutex};
+    mUseNextTransaction = false;
     mNextTransaction = t;
 }
 

libs/gui/include/gui/BLASTBufferQueue.h

diff --git a/libs/gui/include/gui/BLASTBufferQueue.h b/libs/gui/include/gui/BLASTBufferQueue.h
index 1b22df2..64c21e0 100644
--- a/libs/gui/include/gui/BLASTBufferQueue.h
+++ b/libs/gui/include/gui/BLASTBufferQueue.h
@@ -123,6 +123,8 @@
     sp<BLASTBufferItemConsumer> mBufferItemConsumer;
 
     SurfaceComposerClient::Transaction* mNextTransaction GUARDED_BY(mMutex);
+
+    bool mUseNextTransaction = false;
 };
 
 } // namespace android