BufferQueueProducer: Call onBuffersReleased() in detachNextBuffer

Like detachBuffer(), detachNextBuffer() needs to inform the consumer,
who generally has a cache of buffer items, that a buffer is no longer
owned by the buffer queue.

Otherwise the consumer layer can leak the buffer reference until
consumer teardown/disconnect.

Test: Camera CTS is fine, using a camera app shows correct memory
  behavior
Bug: 62591036

Change-Id: I14c200d13e60dbbe21261343941f84fb786db117

1 files changed, 34 insertions, 26 deletions

diff --git a/libs/gui/BufferQueueProducer.cpp b/libs/gui/BufferQueueProducer.cpp
index 3d57769d1a..838586411d 100644
--- a/libs/gui/BufferQueueProducer.cpp
+++ b/libs/gui/BufferQueueProducer.cpp
@@ -632,40 +632,48 @@ status_t BufferQueueProducer::detachNextBuffer(sp<GraphicBuffer>* outBuffer,
         return BAD_VALUE;
     }
 
-    Mutex::Autolock lock(mCore->mMutex);
+    sp<IConsumerListener> listener;
+    {
+        Mutex::Autolock lock(mCore->mMutex);
 
-    if (mCore->mIsAbandoned) {
-        BQ_LOGE("detachNextBuffer: BufferQueue has been abandoned");
-        return NO_INIT;
-    }
+        if (mCore->mIsAbandoned) {
+            BQ_LOGE("detachNextBuffer: BufferQueue has been abandoned");
+            return NO_INIT;
+        }
 
-    if (mCore->mConnectedApi == BufferQueueCore::NO_CONNECTED_API) {
-        BQ_LOGE("detachNextBuffer: BufferQueue has no connected producer");
-        return NO_INIT;
-    }
+        if (mCore->mConnectedApi == BufferQueueCore::NO_CONNECTED_API) {
+            BQ_LOGE("detachNextBuffer: BufferQueue has no connected producer");
+            return NO_INIT;
+        }
 
-    if (mCore->mSharedBufferMode) {
-        BQ_LOGE("detachNextBuffer: cannot detach a buffer in shared buffer "
-            "mode");
-        return BAD_VALUE;
-    }
+        if (mCore->mSharedBufferMode) {
+            BQ_LOGE("detachNextBuffer: cannot detach a buffer in shared buffer "
+                    "mode");
+            return BAD_VALUE;
+        }
 
-    mCore->waitWhileAllocatingLocked();
+        mCore->waitWhileAllocatingLocked();
 
-    if (mCore->mFreeBuffers.empty()) {
-        return NO_MEMORY;
-    }
+        if (mCore->mFreeBuffers.empty()) {
+            return NO_MEMORY;
+        }
 
-    int found = mCore->mFreeBuffers.front();
-    mCore->mFreeBuffers.remove(found);
-    mCore->mFreeSlots.insert(found);
+        int found = mCore->mFreeBuffers.front();
+        mCore->mFreeBuffers.remove(found);
+        mCore->mFreeSlots.insert(found);
 
-    BQ_LOGV("detachNextBuffer detached slot %d", found);
+        BQ_LOGV("detachNextBuffer detached slot %d", found);
 
-    *outBuffer = mSlots[found].mGraphicBuffer;
-    *outFence = mSlots[found].mFence;
-    mCore->clearBufferSlotLocked(found);
-    VALIDATE_CONSISTENCY();
+        *outBuffer = mSlots[found].mGraphicBuffer;
+        *outFence = mSlots[found].mFence;
+        mCore->clearBufferSlotLocked(found);
+        VALIDATE_CONSISTENCY();
+        listener = mCore->mConsumerListener;
+    }
+
+    if (listener != NULL) {
+        listener->onBuffersReleased();
+    }
 
     return NO_ERROR;
 }