From patchwork Thu Mar 22 16:30:44 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sinan Kaya X-Patchwork-Id: 10301871 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 58D4760386 for ; Thu, 22 Mar 2018 16:31:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4BC0928818 for ; Thu, 22 Mar 2018 16:31:48 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 482F42881A; Thu, 22 Mar 2018 16:31:48 +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 A01A728AEB for ; Thu, 22 Mar 2018 16:30:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751375AbeCVQaw (ORCPT ); Thu, 22 Mar 2018 12:30:52 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:41022 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750863AbeCVQav (ORCPT ); Thu, 22 Mar 2018 12:30:51 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id C036260C54; Thu, 22 Mar 2018 16:30:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521736250; bh=hGb4O2x7FjRLDgQ7Cd8PA8ZloLdYMumBeD2pzirvYaQ=; h=From:To:Cc:Subject:Date:From; b=ahGqnluY71YSmK5NfFKqiQGVC2inhD+LBUXXufbGPawn/ZKMzNBkqfut32CgpGKG+ S04zGotqqIYgCifb7i4S5eAyZgpB0GTG0SaYGDuIg6bpIg9Ev1LJ9hNk2MN7w/w0TE P52UVWVqCpNLZTbtlrarBi2uMn20U7hBQct5ve8E= 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 264A060131; Thu, 22 Mar 2018 16:30:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521736250; bh=hGb4O2x7FjRLDgQ7Cd8PA8ZloLdYMumBeD2pzirvYaQ=; h=From:To:Cc:Subject:Date:From; b=ahGqnluY71YSmK5NfFKqiQGVC2inhD+LBUXXufbGPawn/ZKMzNBkqfut32CgpGKG+ S04zGotqqIYgCifb7i4S5eAyZgpB0GTG0SaYGDuIg6bpIg9Ev1LJ9hNk2MN7w/w0TE P52UVWVqCpNLZTbtlrarBi2uMn20U7hBQct5ve8E= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 264A060131 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: linux-rdma@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-kernel@vger.kernel.org Subject: [PATCH v6] RDMA/qedr: eliminate duplicate barriers on weakly-ordered archs #2 Date: Thu, 22 Mar 2018 12:30:44 -0400 Message-Id: <1521736245-23662-1-git-send-email-okaya@codeaurora.org> X-Mailer: git-send-email 2.7.4 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 --- drivers/infiniband/hw/qedr/verbs.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/infiniband/hw/qedr/verbs.c b/drivers/infiniband/hw/qedr/verbs.c index 53f00db..d1cf9a0 100644 --- a/drivers/infiniband/hw/qedr/verbs.c +++ b/drivers/infiniband/hw/qedr/verbs.c @@ -35,6 +35,7 @@ #include #include #include +#include #include #include @@ -860,7 +861,7 @@ static void doorbell_cq(struct qedr_cq *cq, u32 cons, u8 flags) wmb(); cq->db.data.agg_flags = flags; cq->db.data.value = cpu_to_le32(cons); - writeq(cq->db.raw, cq->db_addr); + writeq_relaxed(cq->db.raw, cq->db_addr); /* Make sure write would stick */ mmiowb(); @@ -3338,7 +3339,7 @@ int qedr_post_recv(struct ib_qp *ibqp, struct ib_recv_wr *wr, qp->rq.db_data.data.value++; - writel(qp->rq.db_data.raw, qp->rq.db); + writel_relaxed(qp->rq.db_data.raw, qp->rq.db); /* Make sure write sticks */ mmiowb();