linux-kernel - [PATCH v2] ibmveth: Use dma_alloc_coherent() instead of kmalloc/dma_map

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Date:   Sun, 26 Sep 2021 14:52:14 +0800
From:   Cai Huoqing <caihuoqing@...du.com>
To:     <caihuoqing@...du.com>
CC:     Cristobal Forno <cforno12@...ux.ibm.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        "Paul Mackerras" <paulus@...ba.org>,
        "David S. Miller" <davem@...emloft.net>,
        "Jakub Kicinski" <kuba@...nel.org>, <netdev@...r.kernel.org>,
        <linuxppc-dev@...ts.ozlabs.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH v2] 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@...du.com>
---
v1->v2: Remove extra change in Kconfig

 drivers/net/ethernet/ibm/ibmveth.c | 25 +++++++++----------------
 1 file changed, 9 insertions(+), 16 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmveth.c b/drivers/net/ethernet/ibm/ibmveth.c
index 3d9b4f99d357..3aedb680adb8 100644
--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/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");
 
-- 
2.25.1