From patchwork Wed Mar 14 03:20:24 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sinan Kaya X-Patchwork-Id: 10281403 X-Patchwork-Delegate: jgg@ziepe.ca Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 1C494602BD for ; Wed, 14 Mar 2018 03:22:19 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0CC4F28514 for ; Wed, 14 Mar 2018 03:22:19 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 013682866F; Wed, 14 Mar 2018 03:22:18 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 803B428514 for ; Wed, 14 Mar 2018 03:22:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933385AbeCNDUl (ORCPT ); Tue, 13 Mar 2018 23:20:41 -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 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 431F760854; Wed, 14 Mar 2018 03:20:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1520997639; bh=26oYoO1jY7KROiUtX931ZvHDy54r40T7a7fQCzm8cLw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=S1E/5PhIOiYkO5PxDL2cwhiy07zFqS4k23sDfs3NF/UGcxgXdXEg1IfxZXkaWmne1 7+EpnLV8zl8eQMiaaOurbW5XiILTwJ96zB58LD+ojMqeilU9nTTdCb9rqIhSJqiqjX ZyAeYb0O5TW7r4hiiRq3DQ6ezhg5p+nV2iHeBpk8= Received: from drakthul.qualcomm.com (global_nat1_iad_fw.qualcomm.com [129.46.232.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: okaya@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 89BC66081A; Wed, 14 Mar 2018 03:20:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1520997638; bh=26oYoO1jY7KROiUtX931ZvHDy54r40T7a7fQCzm8cLw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=M3pkfwFBFZe3cIfpFlmk8JHfCUuc2NgRpkgqBXWZEDhHhNGkK+57gdQEYm++mALOg acprLBz3PtBLTmPxsCF5yatNX/fMjO63RyGnYO3dz65hTsAm9US4dGWNblpa9yHKid m2ZqtpunmEl6O+U72UgzDoGmPhx8tXh5eLChp6Mo= 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 Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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(-) 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();