From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: [PATCH] ravb: do not invalidate cache for RX buffer twice Date: Wed, 15 Jul 2015 00:56:52 +0300 Message-ID: <4759713.2ulGRKsd9L@wasted.cogentembedded.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: linux-sh@vger.kernel.org To: netdev@vger.kernel.org Return-path: Received: from mail-lb0-f172.google.com ([209.85.217.172]:33060 "EHLO mail-lb0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750835AbbGNV44 (ORCPT ); Tue, 14 Jul 2015 17:56:56 -0400 Received: by lbbyj8 with SMTP id yj8so14109926lbb.0 for ; Tue, 14 Jul 2015 14:56:55 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: First, dma_sync_single_for_cpu() shouldn't have been called in the first place (it's a streaming DMA API). dma_unmap_single() should have been called instead. Second, dma_unmap_single() call after handing the buffer to napi_gro_receive() makes little sense. Signed-off-by: Sergei Shtylyov --- The patch is against Dave Miller's 'net.git' repo. Don't know why I missed this DMA API misuse while working on the driver. :-< drivers/net/ethernet/renesas/ravb_main.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) Index: net/drivers/net/ethernet/renesas/ravb_main.c =================================================================== --- net.orig/drivers/net/ethernet/renesas/ravb_main.c +++ net/drivers/net/ethernet/renesas/ravb_main.c @@ -543,10 +543,9 @@ static bool ravb_rx(struct net_device *n skb = priv->rx_skb[q][entry]; priv->rx_skb[q][entry] = NULL; - dma_sync_single_for_cpu(&ndev->dev, - le32_to_cpu(desc->dptr), - ALIGN(PKT_BUF_SZ, 16), - DMA_FROM_DEVICE); + dma_unmap_single(&ndev->dev, le32_to_cpu(desc->dptr), + ALIGN(PKT_BUF_SZ, 16), + DMA_FROM_DEVICE); get_ts &= (q == RAVB_NC) ? RAVB_RXTSTAMP_TYPE_V2_L2_EVENT : ~RAVB_RXTSTAMP_TYPE_V2_L2_EVENT; @@ -584,9 +583,6 @@ static bool ravb_rx(struct net_device *n if (!skb) break; /* Better luck next round. */ ravb_set_buffer_align(skb); - dma_unmap_single(&ndev->dev, le32_to_cpu(desc->dptr), - ALIGN(PKT_BUF_SZ, 16), - DMA_FROM_DEVICE); dma_addr = dma_map_single(&ndev->dev, skb->data, le16_to_cpu(desc->ds_cc), DMA_FROM_DEVICE);