commit dbca1353f2c660ec4815da6497ee161cdda721ce
author Ady Abraham <adyabr@google.com> Wed Dec 15 11:58:56 2021 -0800
committer Ady Abraham <adyabr@google.com> Wed Jan 05 14:20:49 2022 -0800
tree 22ec710a86c8c44997f27e0411f8cdae60138259
parent 14e7dc8bc7503d2ca0d525a0e5909c29056f8320

keep a wp<BLASTBufferQueue> in BufferItemConsumer

Use a wp<> instead of raw pointer and remove the mutex around it
to prevent potential deadlocks.

Bug: 208121127
Test: stress test by partner
Test: atest BLASTBufferQueueTest
Change-Id: Iffed80410aeffc9b724d5c01ca2ec589c9622990

libs/gui/BLASTBufferQueue.cpp

diff --git a/libs/gui/BLASTBufferQueue.cpp b/libs/gui/BLASTBufferQueue.cpp
index 34faf87..46de2cb 100644
--- a/libs/gui/BLASTBufferQueue.cpp
+++ b/libs/gui/BLASTBufferQueue.cpp
@@ -119,16 +119,11 @@
     if (needsDisconnect != nullptr) *needsDisconnect = disconnect;
 }
 
-void BLASTBufferItemConsumer::setBlastBufferQueue(BLASTBufferQueue* blastbufferqueue) {
-    std::scoped_lock lock(mBufferQueueMutex);
-    mBLASTBufferQueue = blastbufferqueue;
-}
-
 void BLASTBufferItemConsumer::onSidebandStreamChanged() {
-    std::scoped_lock lock(mBufferQueueMutex);
-    if (mBLASTBufferQueue != nullptr) {
+    sp<BLASTBufferQueue> bbq = mBLASTBufferQueue.promote();
+    if (bbq != nullptr) {
         sp<NativeHandle> stream = getSidebandStream();
-        mBLASTBufferQueue->setSidebandStream(stream);
+        bbq->setSidebandStream(stream);
     }
 }
 
@@ -148,7 +143,7 @@
     mBufferItemConsumer = new BLASTBufferItemConsumer(mConsumer,
                                                       GraphicBuffer::USAGE_HW_COMPOSER |
                                                               GraphicBuffer::USAGE_HW_TEXTURE,
-                                                      1, false);
+                                                      1, false, this);
     static int32_t id = 0;
     mName = name + "#" + std::to_string(id);
     auto consumerName = mName + "(BLAST Consumer)" + std::to_string(id);
@@ -157,7 +152,6 @@
     mBufferItemConsumer->setName(String8(consumerName.c_str()));
     mBufferItemConsumer->setFrameAvailableListener(this);
     mBufferItemConsumer->setBufferFreedListener(this);
-    mBufferItemConsumer->setBlastBufferQueue(this);
 
     ComposerService::getComposerService()->getMaxAcquiredBufferCount(&mMaxAcquiredBuffers);
     mBufferItemConsumer->setMaxAcquiredBufferCount(mMaxAcquiredBuffers);
@@ -174,7 +168,6 @@
 }
 
 BLASTBufferQueue::~BLASTBufferQueue() {
-    mBufferItemConsumer->setBlastBufferQueue(nullptr);
     if (mPendingTransactions.empty()) {
         return;
     }
@@ -1025,7 +1018,6 @@
         mBufferItemConsumer->abandon();
         mBufferItemConsumer->setFrameAvailableListener(nullptr);
         mBufferItemConsumer->setBufferFreedListener(nullptr);
-        mBufferItemConsumer->setBlastBufferQueue(nullptr);
     }
     mBufferItemConsumer = nullptr;
     mConsumer = nullptr;