From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932843AbeCOWX4 (ORCPT ); Thu, 15 Mar 2018 18:23:56 -0400 Received: from mail-wr0-f196.google.com ([209.85.128.196]:46019 "EHLO mail-wr0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932573AbeCOWXw (ORCPT ); Thu, 15 Mar 2018 18:23:52 -0400 X-Google-Smtp-Source: AG47ELu7O3UZa7+cfEPL+y6gcfJ6kXQpNDMplOpn5Dotdv+CTe2G98tprzhDTFJLn5tyKfIdHsgt/Q== Date: Thu, 15 Mar 2018 16:23:46 -0600 From: Jason Gunthorpe To: Sinan Kaya Cc: netdev@vger.kernel.org, timur@codeaurora.org, sulrich@codeaurora.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Michal Kalderon , Ariel Elior , Doug Ledford , linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/7] RDMA/qedr: eliminate duplicate barriers on weakly-ordered archs Message-ID: <20180315222346.GC27537@ziepe.ca> References: <1520997629-17361-1-git-send-email-okaya@codeaurora.org> <1520997629-17361-3-git-send-email-okaya@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1520997629-17361-3-git-send-email-okaya@codeaurora.org> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 13, 2018 at 11:20:24PM -0400, Sinan Kaya wrote: > Code includes wmb() followed by writel() in multiple places. writel() > already has a barrier on some architectures like arm64. > > This ends up CPU observing two barriers back to back before executing the > register write. > > Since code already has an explicit barrier call, changing writel() to > writel_relaxed(). > > Signed-off-by: Sinan Kaya > Acked-by: Jason Gunthorpe > drivers/infiniband/hw/qedr/verbs.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) Applied to RDMA for-next Thanks, Jason