From patchwork Tue Mar 20 02:47:46 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sinan Kaya X-Patchwork-Id: 10296063 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 8290C60385 for ; Tue, 20 Mar 2018 02:49:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7290C28DA8 for ; Tue, 20 Mar 2018 02:49:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 66B3B28E44; Tue, 20 Mar 2018 02:49:42 +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 CF7C428DA8 for ; Tue, 20 Mar 2018 02:49:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751201AbeCTCtk (ORCPT ); Mon, 19 Mar 2018 22:49:40 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:56062 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751014AbeCTCsC (ORCPT ); Mon, 19 Mar 2018 22:48:02 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id F110360F91; Tue, 20 Mar 2018 02:48:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521514082; bh=X1zpRUZ2wV56jV42+Jppglw5loG/W4w5Zw915PF201M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mDiXX+Kl+t7O0IQkPwcunV3ppnaAtA9Ssw7qUax/Q4C+qL382mfKo2lOr4yuSjPBG ikPhfdw+aLLt4oksmyqdNW9SmoNBp9HYDdKRIn9qtnlD5N9zsWOsY0SzwwjEfEooOj B+cCN3TumSQTZGcHjP8n5tPFNagsnnZ+ouU1T2MY= 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 00F3A60FA9; Tue, 20 Mar 2018 02:47:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521514081; bh=X1zpRUZ2wV56jV42+Jppglw5loG/W4w5Zw915PF201M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jB8H9CY4kj+yHhEIzRSwH2KQ2/Avs4jVdGX3QSjdyDnZ01hOvkOzNGbMgQhdQftVw 587Ngj33JcmyQr6CDLGVQotavyj5z9mdV0wHHUvgZuLH3mGYaEA93ndshM7mt7PnO8 wgVtgFK8XAoCX3a2odTqGEjGiRfGEwSnTTTN9bjQ= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 00F3A60FA9 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 , Steve Wise , Doug Ledford , Jason Gunthorpe , linux-kernel@vger.kernel.org Subject: [PATCH v4 4/6] infiniband: cxgb4: Eliminate duplicate barriers on weakly-ordered archs Date: Mon, 19 Mar 2018 22:47:46 -0400 Message-Id: <1521514068-8856-5-git-send-email-okaya@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1521514068-8856-1-git-send-email-okaya@codeaurora.org> References: <1521514068-8856-1-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(). 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: Steve Wise --- drivers/infiniband/hw/cxgb4/t4.h | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/infiniband/hw/cxgb4/t4.h b/drivers/infiniband/hw/cxgb4/t4.h index 8369c7c..6e5658a 100644 --- a/drivers/infiniband/hw/cxgb4/t4.h +++ b/drivers/infiniband/hw/cxgb4/t4.h @@ -457,7 +457,7 @@ static inline void pio_copy(u64 __iomem *dst, u64 *src) int count = 8; while (count) { - writeq(*src, dst); + writeq_relaxed(*src, dst); src++; dst++; count--; @@ -477,15 +477,15 @@ static inline void t4_ring_sq_db(struct t4_wq *wq, u16 inc, union t4_wr *wqe) (u64 *)wqe); } else { pr_debug("DB wq->sq.pidx = %d\n", wq->sq.pidx); - writel(PIDX_T5_V(inc) | QID_V(wq->sq.bar2_qid), - wq->sq.bar2_va + SGE_UDB_KDOORBELL); + writel_relaxed(PIDX_T5_V(inc) | QID_V(wq->sq.bar2_qid), + wq->sq.bar2_va + SGE_UDB_KDOORBELL); } /* Flush user doorbell area writes. */ wmb(); return; } - writel(QID_V(wq->sq.qid) | PIDX_V(inc), wq->db); + writel_relaxed(QID_V(wq->sq.qid) | PIDX_V(inc), wq->db); } static inline void t4_ring_rq_db(struct t4_wq *wq, u16 inc, @@ -502,15 +502,15 @@ static inline void t4_ring_rq_db(struct t4_wq *wq, u16 inc, (void *)wqe); } else { pr_debug("DB wq->rq.pidx = %d\n", wq->rq.pidx); - writel(PIDX_T5_V(inc) | QID_V(wq->rq.bar2_qid), - wq->rq.bar2_va + SGE_UDB_KDOORBELL); + writel_relaxed(PIDX_T5_V(inc) | QID_V(wq->rq.bar2_qid), + wq->rq.bar2_va + SGE_UDB_KDOORBELL); } /* Flush user doorbell area writes. */ wmb(); return; } - writel(QID_V(wq->rq.qid) | PIDX_V(inc), wq->db); + writel_relaxed(QID_V(wq->rq.qid) | PIDX_V(inc), wq->db); } static inline int t4_wq_in_error(struct t4_wq *wq)