Re: [PATCH v2] ethernet:arc: Fix racing of TX ring buffer

Lino Sanfilippo
2016-05-21T23:04:42Z

On 21.05.2016 21:47, Francois Romieu wrote:
> Shuyu Wei <wsy2220-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> :
> [...]
>> diff --git a/drivers/net/ethernet/arc/emac_main.c b/drivers/net/ethernet/arc/emac_main.c
>> index a3a9392..c2447b0 100644
>> --- a/drivers/net/ethernet/arc/emac_main.c
>> +++ b/drivers/net/ethernet/arc/emac_main.c
>> @@ -686,6 +686,9 @@ static int arc_emac_tx(struct sk_buff *skb, struct net_device *ndev)
>>
>> skb_tx_timestamp(skb);
>>
>> + /* Make sure timestamp is set */
>> + smp_wmb();
>
> Should be dma_wmb() (see davem's message).
>
> It's completely unrelated to SMP.
>

Its also completely unrelated to dma so I doubt that this is what davem meant.
As far as I understood he was referring to the dma descriptor.

Lino