AudioFlinger: add specific mutex for client lists

Add a specific mutex to protect access to mClients and
mNotificationClients lists. This avoids locking the main AudioFlinger
mutex from inside thread loops and allows not to worry about
cross deadlocks when sending a config event with status reply while
keeping the ThreadBase or AudioFlinger mutex locked.
As a way of consequence, remove notification client list passed to
processConfigEvents_l() and audioConfigChanged() as the list
can now be accessed by locking client mutex only.

Change-Id: I228022204b6709a8bb60cc96d9514a6ffe59b62e

1 files changed, 9 insertions, 24 deletions

diff --git a/services/audioflinger/Threads.cpp b/services/audioflinger/Threads.cpp
index 470b018..8243a8b 100644
--- a/services/audioflinger/Threads.cpp
+++ b/services/audioflinger/Threads.cpp
@@ -401,8 +401,7 @@ status_t AudioFlinger::ThreadBase::sendSetParameterConfigEvent_l(const String8&
 }
 
 // post condition: mConfigEvents.isEmpty()
-void AudioFlinger::ThreadBase::processConfigEvents_l(
-                    const DefaultKeyedVector< pid_t,sp<NotificationClient> >& notificationClients)
+void AudioFlinger::ThreadBase::processConfigEvents_l()
 {
     bool configChanged = false;
 
@@ -423,7 +422,7 @@ void AudioFlinger::ThreadBase::processConfigEvents_l(
         } break;
         case CFG_EVENT_IO: {
             IoConfigEventData *data = (IoConfigEventData *)event->mData.get();
-            audioConfigChanged_l(notificationClients, data->mEvent, data->mParam);
+            audioConfigChanged(data->mEvent, data->mParam);
         } break;
         case CFG_EVENT_SET_PARAMETER: {
             SetParameterConfigEventData *data = (SetParameterConfigEventData *)event->mData.get();
@@ -1638,15 +1637,11 @@ String8 AudioFlinger::PlaybackThread::getParameters(const String8& keys)
     return out_s8;
 }
 
-// audioConfigChanged_l() must be called with AudioFlinger::mLock held
-void AudioFlinger::PlaybackThread::audioConfigChanged_l(
-                    const DefaultKeyedVector< pid_t,sp<NotificationClient> >& notificationClients,
-                    int event,
-                    int param) {
+void AudioFlinger::PlaybackThread::audioConfigChanged(int event, int param) {
     AudioSystem::OutputDescriptor desc;
     void *param2 = NULL;
 
-    ALOGV("PlaybackThread::audioConfigChanged_l, thread %p, event %d, param %d", this, event,
+    ALOGV("PlaybackThread::audioConfigChanged, thread %p, event %d, param %d", this, event,
             param);
 
     switch (event) {
@@ -1667,7 +1662,7 @@ void AudioFlinger::PlaybackThread::audioConfigChanged_l(
     default:
         break;
     }
-    mAudioFlinger->audioConfigChanged_l(notificationClients, event, mId, param2);
+    mAudioFlinger->audioConfigChanged(event, mId, param2);
 }
 
 void AudioFlinger::PlaybackThread::writeCallback()
@@ -2317,15 +2312,11 @@ bool AudioFlinger::PlaybackThread::threadLoop()
 
         Vector< sp<EffectChain> > effectChains;
 
-        DefaultKeyedVector< pid_t,sp<NotificationClient> > notificationClients =
-                mAudioFlinger->notificationClients();
-
         { // scope for mLock
 
             Mutex::Autolock _l(mLock);
 
-            processConfigEvents_l(notificationClients);
-            notificationClients.clear();
+            processConfigEvents_l();
 
             if (logString != NULL) {
                 mNBLogWriter->logTimestamp();
@@ -4695,14 +4686,11 @@ reacquire_wakelock:
         // activeTracks accumulates a copy of a subset of mActiveTracks
         Vector< sp<RecordTrack> > activeTracks;
 
-        DefaultKeyedVector< pid_t,sp<NotificationClient> > notificationClients =
-                mAudioFlinger->notificationClients();
 
         { // scope for mLock
             Mutex::Autolock _l(mLock);
 
-            processConfigEvents_l(notificationClients);
-            notificationClients.clear();
+            processConfigEvents_l();
 
             // check exitPending here because checkForNewParameters_l() and
             // checkForNewParameters_l() can temporarily release mLock
@@ -5605,10 +5593,7 @@ String8 AudioFlinger::RecordThread::getParameters(const String8& keys)
     return out_s8;
 }
 
-void AudioFlinger::RecordThread::audioConfigChanged_l(
-                    const DefaultKeyedVector< pid_t,sp<NotificationClient> >& notificationClients,
-                    int event,
-                    int param __unused) {
+void AudioFlinger::RecordThread::audioConfigChanged(int event, int param __unused) {
     AudioSystem::OutputDescriptor desc;
     const void *param2 = NULL;
 
@@ -5627,7 +5612,7 @@ void AudioFlinger::RecordThread::audioConfigChanged_l(
     default:
         break;
     }
-    mAudioFlinger->audioConfigChanged_l(notificationClients, event, mId, param2);
+    mAudioFlinger->audioConfigChanged(event, mId, param2);
 }
 
 void AudioFlinger::RecordThread::readInputParameters_l()