Robin Cornelius, Aleric Inglewood: SNOW-196 missing mutexes for texture fetch

Applys a trylock() abort system to allow the worker thread to avoid deadlocks
due to a race between mQueueMutex and mWorkerMutex.

1 files changed, 18 insertions, 10 deletions

diff --git a/linden/indra/newview/lltexturefetch.cpp b/linden/indra/newview/lltexturefetch.cpp
index 8ff9e9f..3a5665c 100644
--- a/linden/indra/newview/lltexturefetch.cpp
+++ b/linden/indra/newview/lltexturefetch.cpp
@@ -744,13 +744,17 @@ bool LLTextureFetchWorker::doWork(S32 param)
                 }
                 else if (mSentRequest == UNSENT)
                 {
-                        // Add this to the network queue and sit here.
-                        // LLTextureFetch::update() will send off a request which will change our state
-                        mRequestedSize = mDesiredSize;
-                        mRequestedDiscard = mDesiredDiscard;
-                        mSentRequest = QUEUED;
-                        mFetcher->addToNetworkQueue(this);
-                        setPriority(LLWorkerThread::PRIORITY_LOW | mWorkPriority);
+                        if(mFetcher->mQueueMutex.tryLock())
+                        {
+                                // Add this to the network queue and sit here.
+                                // LLTextureFetch::update() will send off a request which will change our state
+                                mRequestedSize = mDesiredSize;
+                                mRequestedDiscard = mDesiredDiscard;
+                                mSentRequest = QUEUED;  
+                                mFetcher->addToNetworkQueue(this);
+                                setPriority(LLWorkerThread::PRIORITY_LOW | mWorkPriority);
+                                mFetcher->mQueueMutex.unlock();
+                        }
                         return false;
                 }
                 else
@@ -800,7 +804,7 @@ bool LLTextureFetchWorker::doWork(S32 param)
                         // Set the throttle to the entire bandwidth, assuming UDP packets will get priority
                         // when they are needed
                         F32 max_bandwidth = mFetcher->mMaxBandwidth;
-                        if ((mFetcher->getHTTPQueueSize() >= HTTP_QUEUE_MAX_SIZE) ||
+                        if ((mFetcher->getNumHTTPRequests() >= HTTP_QUEUE_MAX_SIZE) ||
                                 (mFetcher->getTextureBandwidth() > max_bandwidth))
                         {
                                 // Make normal priority and return (i.e. wait until there is room in the queue)
@@ -1469,12 +1473,13 @@ void LLTextureFetch::deleteRequest(const LLUUID& id, bool cancel)
         }
 }
 
+// Need to hold mQueueMutex when entering this function SNOW-196
+// Snowglobe ToDo fix holding mQueueMutex over the entire function, we only need
+// it for the mRequestMap access
 // protected
 void LLTextureFetch::addToNetworkQueue(LLTextureFetchWorker* worker)
 {
-        mQueueMutex.lock();
         bool is_worker_in_request_map = (mRequestMap.find(worker->mID) != mRequestMap.end());
-        mQueueMutex.unlock();
 
         LLMutexLock lock(&mNetworkQueueMutex);
         if (is_worker_in_request_map)
@@ -1916,6 +1921,7 @@ bool LLTextureFetch::receiveImageHeader(const LLHost& host, const LLUUID& id, U8
         {
 //              llwarns << "Received header for non active worker: " << id << llendl;
                 ++mBadPacketCount;
+                LLMutexLock lock2(&mNetworkQueueMutex);
                 mCancelQueue[host].insert(id);
                 return false;
         }
@@ -1944,6 +1950,7 @@ bool LLTextureFetch::receiveImageHeader(const LLHost& host, const LLUUID& id, U8
         if (!res)
         {
                 ++mBadPacketCount;
+                LLMutexLock lock2(&mNetworkQueueMutex);
                 mCancelQueue[host].insert(id);
         }
         else
@@ -1988,6 +1995,7 @@ bool LLTextureFetch::receiveImagePacket(const LLHost& host, const LLUUID& id, U1
         if (!res)
         {
                 ++mBadPacketCount;
+                LLMutexLock lock2(&mNetworkQueueMutex);
                 mCancelQueue[host].insert(id);
                 return false;
         }