Merge branch 'buffer_transform' into 'master'

fix: fix the GPU buffer transform error

See merge request applied-machine-learning/sysml/mace!1335

mace/ops/opencl/buffer_transformer.h

@@ -67,11 +67,13 @@ class OpenCLBufferTransformer {
                 << " with data type " << dt;
         internal_tensor->Resize(input->shape());
         const uint8_t *input_ptr = input->data<uint8_t>();
-        // No need to finish the opencl command queue to write to the tensor
-        // from CPU, this can accelerate the mapping if using ION buffer.
-        Tensor::MappingGuard guard(internal_tensor, false);
-        uint8_t *internal_ptr = internal_tensor->mutable_data<uint8_t>();
-        memcpy(internal_ptr, input_ptr, input->raw_size());
+        {
+          // No need to finish the opencl command queue to write to the tensor
+          // from CPU, this can accelerate the mapping if using ION buffer.
+          Tensor::MappingGuard guard(internal_tensor, false);
+          uint8_t *internal_ptr = internal_tensor->mutable_data<uint8_t>();
+          memcpy(internal_ptr, input_ptr, input->raw_size());
+        }
         // 2. convert the internal GPU Buffer to output.
         return kernel_->Compute(
             context, internal_tensor, type, wino_blk_size, output);