Re: [PATCH] net/mlx4_en: ensure rx_desc updating reaches HW before prod db updating

[jianchao.wang]

Hi Tariq

Thanks for your kindly response.

On 01/14/2018 05:47 PM, Tariq Toukan wrote:
> Thanks Jianchao for your patch.
> 
> And Thank you guys for your reviews, much appreciated.
> I was off-work on Friday and Saturday.
> 
> On 14/01/2018 4:40 AM, jianchao.wang wrote:
>> Dear all
>>
>> Thanks for the kindly response and reviewing. That's really appreciated.
>>
>> On 01/13/2018 12:46 AM, Eric Dumazet wrote:
>>>> Does this need to be dma_wmb(), and should it be in
>>>> mlx4_en_update_rx_prod_db ?
>>>>
>>> +1 on dma_wmb()
>>>
>>> On what architecture bug was observed ?
>> This issue was observed on x86-64.
>> And I will send a new patch, in which replace wmb() with dma_wmb(), to customer
>> to confirm.
> 
> +1 on dma_wmb, let us know once customer confirms.
> Please place it within mlx4_en_update_rx_prod_db as suggested.
Yes, I have recommended it to customer.
Once I get the result, I will share it here.
> All other calls to mlx4_en_update_rx_prod_db are in control/slow path so I prefer being on the safe side, and care less about bulking the barrier.
> 
> Thanks,
> Tariq
>