commit 021cf9634ab09c0753a40b7c9ef4ba603be5c3da
author Eric Laurent <elaurent@google.com> Tue May 13 10:18:14 2014 -0700
committer Eric Laurent <elaurent@google.com> Tue May 13 13:09:17 2014 -0700
tree 03fb2a864179983e482cae4dac6a502a6dcef136
parent aa0315f9fdcf99e84a969a4f81192150ddaef260

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

services/audioflinger/Threads.cpp

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 @@
 }
 
 // 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 @@
         } 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 @@
     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 @@
     default:
         break;
     }
-    mAudioFlinger->audioConfigChanged_l(notificationClients, event, mId, param2);
+    mAudioFlinger->audioConfigChanged(event, mId, param2);
 }
 
 void AudioFlinger::PlaybackThread::writeCallback()
@@ -2317,15 +2312,11 @@
 
         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 @@
         // 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 @@
     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 @@
     default:
         break;
     }
-    mAudioFlinger->audioConfigChanged_l(notificationClients, event, mId, param2);
+    mAudioFlinger->audioConfigChanged(event, mId, param2);
 }
 
 void AudioFlinger::RecordThread::readInputParameters_l()