From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752434AbeCTCsQ (ORCPT ); Mon, 19 Mar 2018 22:48:16 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:56248 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752411AbeCTCsG (ORCPT ); Mon, 19 Mar 2018 22:48:06 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 7275F60C54 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 v4 6/6] RDMA/qedr: eliminate duplicate barriers on weakly-ordered archs #2 Date: Mon, 19 Mar 2018 22:47:48 -0400 Message-Id: <1521514068-8856-7-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 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 ccd55f4..db60360 100644 --- a/drivers/infiniband/hw/qedr/verbs.c +++ b/drivers/infiniband/hw/qedr/verbs.c @@ -860,7 +860,7 @@ 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 +3338,7 @@ 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(); -- 2.7.4