ntb_perf: avoid false dma unmap of destination address

The DMA map and unmap of destination address is already being
done in perf_init_test() and perf_clear_test() functions.
Hence avoiding it by making necessary changes in perf_copy_chunk()
function.
Signed-off-by: NSanjay R Mehta <sanju.mehta@amd.com>
Signed-off-by: NArindam Nath <arindam.nath@amd.com>
Signed-off-by: NJon Mason <jdmason@kudzu.us>

drivers/ntb/test/ntb_perf.c

@@ -804,7 +804,7 @@ static int perf_copy_chunk(struct perf_thread *pthr,
 	dst_vaddr = dst;
 	dst_dma_addr = peer->dma_dst_addr + (dst_vaddr - vbase);
 
-	unmap = dmaengine_get_unmap_data(dma_dev, 2, GFP_NOWAIT);
+	unmap = dmaengine_get_unmap_data(dma_dev, 1, GFP_NOWAIT);
 	if (!unmap)
 		return -ENOMEM;
 
@@ -817,15 +817,8 @@ static int perf_copy_chunk(struct perf_thread *pthr,
 	}
 	unmap->to_cnt = 1;
 
-	unmap->addr[1] = dst_dma_addr;
-	if (dma_mapping_error(dma_dev, unmap->addr[1])) {
-		ret = -EIO;
-		goto err_free_resource;
-	}
-	unmap->from_cnt = 1;
-
 	do {
-		tx = dmaengine_prep_dma_memcpy(pthr->dma_chan, unmap->addr[1],
+		tx = dmaengine_prep_dma_memcpy(pthr->dma_chan, dst_dma_addr,
 			unmap->addr[0], len, DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 		if (!tx)
 			msleep(DMA_MDELAY);