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

[Tariq Toukan]

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.
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