From mboxrd@z Thu Jan 1 00:00:00 1970 From: "jianchao.wang" Subject: Re: [PATCH] net/mlx4_en: ensure rx_desc updating reaches HW before prod db updating Date: Mon, 15 Jan 2018 13:50:34 +0800 Message-ID: References: <1515728542-3060-1-git-send-email-jianchao.w.wang@oracle.com> <20180112163247.GB15974@ziepe.ca> <1515775567.131759.42.camel@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Tariq Toukan , Eric Dumazet , Jason Gunthorpe Cc: junxiao.bi@oracle.com, netdev@vger.kernel.org, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, Saeed Mahameed List-Id: linux-rdma@vger.kernel.org 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 >