DO NOT MERGE - improve audio effect framwework thread safety

- Reorganize handle effect creation code to make sure the effect engine
is created with both thread and effect chain mutex held.
- Reorganize handle disconnect code to make sure the effect engine
is released with both thread and effect chain mutex held.
- Protect IEffect interface methods in EffectHande with a Mutex.
- Only pin effect if the session was acquired first.
- Do not use strong pointer to EffectModule in EffectHandles:
only the EffectChain has a single strong reference to the EffectModule.

Bug: 32707507
Change-Id: Ia1098cba2cd32cc2d1c9dfdff4adc2388dfed80e
(cherry picked from commit b378b73)

services/audioflinger/AudioFlinger.cpp

@@ -1105,7 +1105,7 @@ void AudioFlinger::removeNotificationClient(pid_t pid)
     ALOGV("%d died, releasing its sessions", pid);
     size_t num = mAudioSessionRefs.size();
     bool removed = false;
-    for (size_t i = 0; i< num; ) {
+    for (size_t i = 0; i < num; ) {
         AudioSessionRef *ref = mAudioSessionRefs.itemAt(i);
         ALOGV(" pid %d @ %d", ref->mPid, i);
         if (ref->mPid == pid) {
@@ -1886,7 +1886,7 @@ void AudioFlinger::acquireAudioSessionId(int audioSession)
     }
 
     size_t num = mAudioSessionRefs.size();
-    for (size_t i = 0; i< num; i++) {
+    for (size_t i = 0; i < num; i++) {
         AudioSessionRef *ref = mAudioSessionRefs.editItemAt(i);
         if (ref->mSessionid == audioSession && ref->mPid == caller) {
             ref->mCnt++;
@@ -1904,7 +1904,7 @@ void AudioFlinger::releaseAudioSessionId(int audioSession)
     pid_t caller = IPCThreadState::self()->getCallingPid();
     ALOGV("releasing %d from %d", audioSession, caller);
     size_t num = mAudioSessionRefs.size();
-    for (size_t i = 0; i< num; i++) {
+    for (size_t i = 0; i < num; i++) {
         AudioSessionRef *ref = mAudioSessionRefs.itemAt(i);
         if (ref->mSessionid == audioSession && ref->mPid == caller) {
             ref->mCnt--;
@@ -1922,6 +1922,18 @@ void AudioFlinger::releaseAudioSessionId(int audioSession)
     ALOGW_IF(caller != getpid_cached, "session id %d not found for pid %d", audioSession, caller);
 }
 
+bool AudioFlinger::isSessionAcquired_l(int audioSession)
+{
+    size_t num = mAudioSessionRefs.size();
+    for (size_t i = 0; i < num; i++) {
+        AudioSessionRef *ref = mAudioSessionRefs.itemAt(i);
+        if (ref->mSessionid == audioSession) {
+            return true;
+        }
+    }
+    return false;
+}
+
 void AudioFlinger::purgeStaleEffects_l() {
 
     ALOGV("purging stale effects");
@@ -2254,8 +2266,9 @@ sp<IEffect> AudioFlinger::createEffect(
         sp<Client> client = registerPid_l(pid);
 
         // create effect on selected output thread
+        bool pinned = (sessionId > AUDIO_SESSION_OUTPUT_MIX) && isSessionAcquired_l(sessionId);
         handle = thread->createEffect_l(client, effectClient, priority, sessionId,
-                &desc, enabled, &lStatus);
+                &desc, enabled, &lStatus, pinned);
         if (handle != 0 && id != NULL) {
             *id = handle->id();
         }

services/audioflinger/AudioFlinger.h

@@ -467,9 +467,9 @@ class AudioFlinger :
 
                 void        removeClient_l(pid_t pid);
                 void        removeNotificationClient(pid_t pid);
-
                 bool isNonOffloadableGlobalEffectEnabled_l();
                 void onNonOffloadableGlobalEffectEnable();
+                bool isSessionAcquired_l(int audioSession);
 
     class AudioHwDevice {
     public: