From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: [PATCH v3 05/11] net: calxedaxgmac: update ring buffer tx_head after barriers Date: Fri, 30 Aug 2013 16:49:23 -0500 Message-ID: <1377899369-23252-5-git-send-email-robherring2@gmail.com> References: <1377899369-23252-1-git-send-email-robherring2@gmail.com> Cc: Ben Hutchings , Lennert Buytenhek , Rob Herring To: netdev@vger.kernel.org Return-path: Received: from mail-ob0-f175.google.com ([209.85.214.175]:60064 "EHLO mail-ob0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756786Ab3H3VuD (ORCPT ); Fri, 30 Aug 2013 17:50:03 -0400 Received: by mail-ob0-f175.google.com with SMTP id xn12so2430392obc.6 for ; Fri, 30 Aug 2013 14:50:01 -0700 (PDT) In-Reply-To: <1377899369-23252-1-git-send-email-robherring2@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Rob Herring Ensure that the descriptor writes are visible before the ring buffer head is updated. Since writel is a barrier, we can simply update the head after the writel. Reported-by: Lennert Buytenhek Signed-off-by: Rob Herring --- drivers/net/ethernet/calxeda/xgmac.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/calxeda/xgmac.c b/drivers/net/ethernet/calxeda/xgmac.c index 64854ad..f630855 100644 --- a/drivers/net/ethernet/calxeda/xgmac.c +++ b/drivers/net/ethernet/calxeda/xgmac.c @@ -1121,9 +1121,10 @@ static netdev_tx_t xgmac_xmit(struct sk_buff *skb, struct net_device *dev) wmb(); desc_set_tx_owner(first, desc_flags | TXDESC_FIRST_SEG); + writel(1, priv->base + XGMAC_DMA_TX_POLL); + priv->tx_head = dma_ring_incr(entry, DMA_TX_RING_SZ); - writel(1, priv->base + XGMAC_DMA_TX_POLL); if (dma_ring_space(priv->tx_head, priv->tx_tail, DMA_TX_RING_SZ) < MAX_SKB_FRAGS) netif_stop_queue(dev); -- 1.8.1.2