From mboxrd@z Thu Jan  1 00:00:00 1970
From: dingtianhong@huawei.com (Ding Tianhong)
Date: Thu, 16 Apr 2015 14:26:21 +0800
Subject: [PATCH net-next 4/6] net: hip04: Don't free the tx skb when the
 buffer is not ready for xmit
In-Reply-To: <2218546.M1hzu1bzfh@wuerfel>
References: <1429101008-9464-1-git-send-email-dingtianhong@huawei.com>
 <1429101008-9464-5-git-send-email-dingtianhong@huawei.com>
 <2218546.M1hzu1bzfh@wuerfel>
Message-ID: <552F560D.4070309@huawei.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On 2015/4/15 22:19, Arnd Bergmann wrote:
> 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
> 
Yes, the smp_wmb() could only make sure the tx buffer was ready to xmit.

> .
>