From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933403AbeCNDUm (ORCPT ); Tue, 13 Mar 2018 23:20:42 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:43230 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933384AbeCNDUj (ORCPT ); Tue, 13 Mar 2018 23:20:39 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 89BC66081A Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=okaya@codeaurora.org From: Sinan Kaya To: netdev@vger.kernel.org, timur@codeaurora.org, sulrich@codeaurora.org Cc: linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Sinan Kaya , Michal Kalderon , Ariel Elior , Doug Ledford , Jason Gunthorpe , linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 3/7] RDMA/qedr: eliminate duplicate barriers on weakly-ordered archs Date: Tue, 13 Mar 2018 23:20:24 -0400 Message-Id: <1520997629-17361-3-git-send-email-okaya@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1520997629-17361-1-git-send-email-okaya@codeaurora.org> References: <1520997629-17361-1-git-send-email-okaya@codeaurora.org> MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- drivers/infiniband/hw/qedr/verbs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/infiniband/hw/qedr/verbs.c b/drivers/infiniband/hw/qedr/verbs.c index 53f00db..ccd55f4 100644 --- a/drivers/infiniband/hw/qedr/verbs.c +++ b/drivers/infiniband/hw/qedr/verbs.c @@ -1870,7 +1870,7 @@ static int qedr_update_qp_state(struct qedr_dev *dev, if (rdma_protocol_roce(&dev->ibdev, 1)) { wmb(); - writel(qp->rq.db_data.raw, qp->rq.db); + writel_relaxed(qp->rq.db_data.raw, qp->rq.db); /* Make sure write takes effect */ mmiowb(); } @@ -3247,7 +3247,7 @@ int qedr_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr, * redundant doorbell. */ wmb(); - writel(qp->sq.db_data.raw, qp->sq.db); + writel_relaxed(qp->sq.db_data.raw, qp->sq.db); /* Make sure write sticks */ mmiowb(); -- 2.7.4