From mboxrd@z Thu Jan  1 00:00:00 1970
From: Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH net-next 4/6] net: hip04: Don't free the tx skb when the buffer is not ready for xmit
Date: Wed, 15 Apr 2015 16:19:59 +0200
Message-ID: <2218546.M1hzu1bzfh@wuerfel>
References: <1429101008-9464-1-git-send-email-dingtianhong@huawei.com> <1429101008-9464-5-git-send-email-dingtianhong@huawei.com>
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To: Ding Tianhong <dingtianhong@huawei.com>
Cc: davem@davemloft.net, grant.likely@linaro.org, sergei.shtylyov@cogentembedded.com, linux-arm-kernel@lists.infradead.org, eric.dumazet@gmail.com, zhangfei.gao@linaro.org, joe@perches.com, netdev@vger.kernel.org, devicetree@vger.kernel.org, linux@arm.linux.org.uk
List-Id: devicetree@vger.kernel.org

On Wednesday 15 April 2015 20:30:06 Ding Tianhong wrote:
> @@ -489,6 +487,8 @@ static int hip04_mac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
>  
>         /* Ensure tx_head update visible to tx reclaim */
>         smp_wmb();
> +       count++;
> +       priv->tx_head = TX_NEXT(tx_head);
>  
> 

Something is wrong here, the comment does not match the code any more, because
the smp_wmb() won't actually make the tx_head update visible.

	Arnd