ibmveth: Use dma_alloc_coherent() instead of kmalloc/dma_map_single()

Replacing kmalloc/kfree/dma_map_single/dma_unmap_single()
with dma_alloc_coherent/dma_free_coherent() helps to reduce
code size, and simplify the code, and coherent DMA will not
clear the cache every time.
Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/ibm/ibmveth.c

@@ -605,17 +605,13 @@ static int ibmveth_open(struct net_device *netdev)
 	}
 
 	rc = -ENOMEM;
-	adapter->bounce_buffer =
-	    kmalloc(netdev->mtu + IBMVETH_BUFF_OH, GFP_KERNEL);
-	if (!adapter->bounce_buffer)
-		goto out_free_irq;
 
-	adapter->bounce_buffer_dma =
-	    dma_map_single(&adapter->vdev->dev, adapter->bounce_buffer,
-			   netdev->mtu + IBMVETH_BUFF_OH, DMA_BIDIRECTIONAL);
-	if (dma_mapping_error(dev, adapter->bounce_buffer_dma)) {
-		netdev_err(netdev, "unable to map bounce buffer\n");
-		goto out_free_bounce_buffer;
+	adapter->bounce_buffer = dma_alloc_coherent(&adapter->vdev->dev,
+						    netdev->mtu + IBMVETH_BUFF_OH,
+						    &adapter->bounce_buffer_dma, GFP_KERNEL);
+	if (!adapter->bounce_buffer) {
+		netdev_err(netdev, "unable to alloc bounce buffer\n");
+		goto out_free_irq;
 	}
 
 	netdev_dbg(netdev, "initial replenish cycle\n");
@@ -627,8 +623,6 @@ static int ibmveth_open(struct net_device *netdev)
 
 	return 0;
 
-out_free_bounce_buffer:
-	kfree(adapter->bounce_buffer);
 out_free_irq:
 	free_irq(netdev->irq, netdev);
 out_free_buffer_pools:
@@ -702,10 +696,9 @@ static int ibmveth_close(struct net_device *netdev)
 			ibmveth_free_buffer_pool(adapter,
 						 &adapter->rx_buff_pool[i]);
 
-	dma_unmap_single(&adapter->vdev->dev, adapter->bounce_buffer_dma,
-			 adapter->netdev->mtu + IBMVETH_BUFF_OH,
-			 DMA_BIDIRECTIONAL);
-	kfree(adapter->bounce_buffer);
+	dma_free_coherent(&adapter->vdev->dev,
+			  adapter->netdev->mtu + IBMVETH_BUFF_OH,
+			  adapter->bounce_buffer, adapter->bounce_buffer_dma);
 
 	netdev_dbg(netdev, "close complete\n");