Pass the thread pool into ReduceKernel

This was overlooked when enabling setting a custom thread pool
for various concurrent methods.

Fixes: QTBUG-53465
Change-Id: I189a7776fa02bbc3e995538cc154a7246ad1ad7a
Reviewed-by: Sona Kurazyan <sona.kurazyan@qt.io>

src/concurrent/qtconcurrentfilterkernel.h

@@ -93,7 +93,7 @@ public:
           sequence(_sequence),
           keep(_keep),
           reduce(_reduce),
-          reducer(OrderedReduce)
+          reducer(pool, OrderedReduce)
     { }
 
     bool runIteration(typename Sequence::const_iterator it, int index, T *) override
@@ -173,7 +173,7 @@ public:
                           ReduceFunctor _reduce,
                           ReduceOptions reduceOption)
         : IterateKernelType(pool, begin, end), reducedResult(), keep(_keep), reduce(_reduce),
-          reducer(reduceOption)
+          reducer(pool, reduceOption)
     { }
 
     FilteredReducedKernel(QThreadPool *pool, Iterator begin, Iterator end, KeepFunctor _keep,
@@ -183,7 +183,7 @@ public:
           reducedResult(std::forward<ReducedResultType>(initialValue)),
           keep(_keep),
           reduce(_reduce),
-          reducer(reduceOption)
+          reducer(pool, reduceOption)
     {
     }
 

src/concurrent/qtconcurrentmapkernel.h

@@ -103,7 +103,7 @@ public:
     MappedReducedKernel(QThreadPool *pool, Iterator begin, Iterator end, MapFunctor _map,
                         ReduceFunctor _reduce, ReduceOptions reduceOptions)
         : IterateKernel<Iterator, ReducedResultType>(pool, begin, end), reducedResult(),
-          map(_map), reduce(_reduce), reducer(reduceOptions)
+          map(_map), reduce(_reduce), reducer(pool, reduceOptions)
     { }
 
     MappedReducedKernel(QThreadPool *pool, Iterator begin, Iterator end, MapFunctor _map,
@@ -113,7 +113,7 @@ public:
           reducedResult(std::forward<ReducedResultType>(initialValue)),
           map(_map),
           reduce(_reduce),
-          reducer(reduceOptions)
+          reducer(pool, reduceOptions)
     {
     }
 

src/concurrent/qtconcurrentreducekernel.h

@@ -140,9 +140,9 @@ class ReduceKernel
     }
 
 public:
-    ReduceKernel(ReduceOptions _reduceOptions)
+    ReduceKernel(QThreadPool *pool, ReduceOptions _reduceOptions)
         : reduceOptions(_reduceOptions), progress(0), resultsMapSize(0),
-          threadCount(QThreadPool::globalInstance()->maxThreadCount())
+          threadCount(pool->maxThreadCount())
     { }
 
     void runReduce(ReduceFunctor &reduce,