Merge "Revert "Revert "AudioPolicyService: fix race in AudioCommandThread""" into mnc-dev am: 6919fbe40d am: 8c5b71ce47 am: 2fb59515d4
am: 77249c550f

* commit '77249c550ffc97b5f92150d544e661e17d530332':
  Revert "Revert "AudioPolicyService: fix race in AudioCommandThread""
diff --git a/services/audiopolicy/service/AudioPolicyService.cpp b/services/audiopolicy/service/AudioPolicyService.cpp
index 619e5c1..cdde605 100644
--- a/services/audiopolicy/service/AudioPolicyService.cpp
+++ b/services/audiopolicy/service/AudioPolicyService.cpp
@@ -580,22 +580,28 @@
                     }
                 }
                 waitTime = INT64_MAX;
+                // release mLock before releasing strong reference on the service as
+                // AudioPolicyService destructor calls AudioCommandThread::exit() which
+                // acquires mLock.
+                mLock.unlock();
+                svc.clear();
+                mLock.lock();
             } else {
                 waitTime = mAudioCommands[0]->mTime - curTime;
                 break;
             }
         }
-        // release mLock before releasing strong reference on the service as
-        // AudioPolicyService destructor calls AudioCommandThread::exit() which acquires mLock.
-        mLock.unlock();
-        svc.clear();
-        mLock.lock();
-        if (!exitPending() && (mAudioCommands.isEmpty() || waitTime != INT64_MAX)) {
-            // release delayed commands wake lock
+
+        // release delayed commands wake lock if the queue is empty
+        if (mAudioCommands.isEmpty()) {
             release_wake_lock(mName.string());
+        }
+
+        // At this stage we have either an empty command queue or the first command in the queue
+        // has a finite delay. So unless we are exiting it is safe to wait.
+        if (!exitPending()) {
             ALOGV("AudioCommandThread() going to sleep");
             mWaitWorkCV.waitRelative(mLock, waitTime);
-            ALOGV("AudioCommandThread() waking up");
         }
     }
     // release delayed commands wake lock before quitting
@@ -1006,6 +1012,8 @@
         requestExit();
         mWaitWorkCV.signal();
     }
+    // Note that we can call it from the thread loop if all other references have been released
+    // but it will safely return WOULD_BLOCK in this case
     requestExitAndWait();
 }