3 files changed, 20 insertions, 65 deletions

diff --git a/linden/indra/llcommon/llthread.cpp b/linden/indra/llcommon/llthread.cpp
index 60ccd5c..692d6c4 100644
--- a/linden/indra/llcommon/llthread.cpp
+++ b/linden/indra/llcommon/llthread.cpp
@@ -283,7 +283,6 @@ LLMutex::LLMutex(apr_pool_t *poolp) :
         apr_thread_mutex_create(&mAPRMutexp, APR_THREAD_MUTEX_UNNESTED, mAPRPoolp);
 }
 
-
 LLMutex::~LLMutex()
 {
 #if _DEBUG
@@ -297,40 +296,14 @@ LLMutex::~LLMutex()
         }
 }
 
-
-void LLMutex::lock()
-{
-        apr_thread_mutex_lock(mAPRMutexp);
-}
-
-void LLMutex::unlock()
-{
-        apr_thread_mutex_unlock(mAPRMutexp);
-}
-
 bool LLMutex::isLocked()
 {
-        apr_status_t status = apr_thread_mutex_trylock(mAPRMutexp);
-        if (APR_STATUS_IS_EBUSY(status))
+        if (!tryLock())
         {
                 return true;
         }
-        else
-        {
-                apr_thread_mutex_unlock(mAPRMutexp);
-                return false;
-        }
-}
-
-//trys to grab a lock and if sucessful returns true
-bool LLMutex::tryLock()
-{
-        apr_status_t status = apr_thread_mutex_trylock(mAPRMutexp);
-        if (APR_STATUS_IS_EBUSY(status))
-        {       
-                return false;
-        }
-        return true;
+        apr_thread_mutex_unlock(mAPRMutexp);
+        return false;
 }
 
 //============================================================================
@@ -343,14 +316,12 @@ LLCondition::LLCondition(apr_pool_t *poolp) :
         apr_thread_cond_create(&mAPRCondp, mAPRPoolp);
 }
 
-
 LLCondition::~LLCondition()
 {
         apr_thread_cond_destroy(mAPRCondp);
         mAPRCondp = NULL;
 }
 
-
 void LLCondition::wait()
 {
         apr_thread_cond_wait(mAPRCondp, mAPRMutexp);
diff --git a/linden/indra/llcommon/llthread.h b/linden/indra/llcommon/llthread.h
index d773fa4..ed76a3b 100644
--- a/linden/indra/llcommon/llthread.h
+++ b/linden/indra/llcommon/llthread.h
@@ -131,10 +131,12 @@ public:
         LLMutex(apr_pool_t *apr_poolp); // NULL pool constructs a new pool for the mutex
         ~LLMutex();
         
-        void lock();            // blocks
-        void unlock();
+        void lock() { apr_thread_mutex_lock(mAPRMutexp); }
+        void unlock() { apr_thread_mutex_unlock(mAPRMutexp); }
+        // Returns true if lock was obtained successfully.
+        bool tryLock() { return !APR_STATUS_IS_EBUSY(apr_thread_mutex_trylock(mAPRMutexp)); }
+
         bool isLocked();        // non-blocking, but does do a lock/unlock so not free
-        bool tryLock();         //non-blocking, but not free, returns true if grabed lock
 
 protected:
         apr_thread_mutex_t *mAPRMutexp;
diff --git a/linden/indra/newview/lltexturefetch.cpp b/linden/indra/newview/lltexturefetch.cpp
index 3a5665c..62b4c8b 100644
--- a/linden/indra/newview/lltexturefetch.cpp
+++ b/linden/indra/newview/lltexturefetch.cpp
@@ -744,26 +744,17 @@ bool LLTextureFetchWorker::doWork(S32 param)
                 }
                 else if (mSentRequest == UNSENT)
                 {
-                        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();
-                        }
+                        // 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);
                         return false;
                 }
                 else
                 {
-                        // Shouldn't need to do anything here
-                        //llassert_always(mFetcher->mNetworkQueue.find(mID) != mFetcher->mNetworkQueue.end());
-                        // Make certain this is in the network queue
-                        //mFetcher->addToNetworkQueue(this);
-                        //setPriority(LLWorkerThread::PRIORITY_LOW | mWorkPriority);
                         return false;
                 }
         }
@@ -1473,23 +1464,12 @@ 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)
 {
-        bool is_worker_in_request_map = (mRequestMap.find(worker->mID) != mRequestMap.end());
-
         LLMutexLock lock(&mNetworkQueueMutex);
-        if (is_worker_in_request_map)
-        {
-                // only add to the queue if in the request map
-                // i.e. a delete has not been requested
-                mNetworkQueue.insert(worker->mID);
-        }
-        for (cancel_queue_t::iterator iter1 = mCancelQueue.begin();
-                 iter1 != mCancelQueue.end(); ++iter1)
+        mNetworkQueue.insert(worker->mID);
+        for (cancel_queue_t::iterator iter1 = mCancelQueue.begin(); iter1 != mCancelQueue.end(); ++iter1)
         {
                 iter1->second.erase(worker->mID);
         }
@@ -1715,8 +1695,10 @@ void LLTextureFetch::sendRequestListToSimulators()
                 LLTextureFetchWorker* req = getWorker(*curiter);
                 if (!req)
                 {
+                        // This happens when a request was removed from mRequestMap in a race
+                        // with adding it to mNetworkQueue by doWork (see SNOW-196).
                         mNetworkQueue.erase(curiter);
-                        continue; // paranoia
+                        continue;
                 }
                 llassert(req->mState == LLTextureFetchWorker::LOAD_FROM_NETWORK || LLTextureFetchWorker::LOAD_FROM_SIMULATOR);
                 if ((req->mState != LLTextureFetchWorker::LOAD_FROM_NETWORK) &&