!1438 GPU GetNext kernel fix

Merge pull request !1438 from chenweifeng/getnext

mindspore/ccsrc/kernel/gpu/data/dataset_iterator_kernel.cc

@@ -64,7 +64,7 @@ bool DatasetIteratorKernel::Init(const CNodePtr &kernel_node) {
 void DatasetIteratorKernel::InitSizeLists() { return; }
 
 bool DatasetIteratorKernel::Launch(const std::vector<AddressPtr> &, const std::vector<AddressPtr> &,
-                                   const std::vector<AddressPtr> &outputs, void *) {
+                                   const std::vector<AddressPtr> &outputs, void *stream) {
   void *addr = nullptr;
   size_t len = 0;
 
@@ -96,11 +96,14 @@ bool DatasetIteratorKernel::Launch(const std::vector<AddressPtr> &, const std::v
   }
 
   for (size_t i = 0; i < output_size_list_.size(); i++) {
-    CHECK_CUDA_RET_WITH_EXCEPT(cudaMemcpy(outputs[i]->addr, addr, output_size_list_[i], cudaMemcpyDeviceToDevice),
+    CHECK_CUDA_RET_WITH_EXCEPT(cudaMemcpyAsync(outputs[i]->addr, addr, output_size_list_[i], cudaMemcpyDeviceToDevice,
+                                               reinterpret_cast<cudaStream_t>(stream)),
                                "Cuda Memcpy Failed");
     addr = reinterpret_cast<unsigned char *>(addr) + output_size_list_[i];
   }
 
+  CHECK_CUDA_RET_WITH_EXCEPT(cudaStreamSynchronize(reinterpret_cast<cudaStream_t>(stream)),
+                             "cudaStreamSynchronize failed");
   (void)GpuBufferMgr::GetInstance().Pop(handle_);
   return true;
 }