From patchwork Thu Mar 22 16:26:49 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sinan Kaya X-Patchwork-Id: 10301863 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 B4E29605F3 for ; Thu, 22 Mar 2018 16:27:25 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A8C3D28795 for ; Thu, 22 Mar 2018 16:27:25 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9D1762879B; Thu, 22 Mar 2018 16:27:25 +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 46EBB28797 for ; Thu, 22 Mar 2018 16:27:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751819AbeCVQ1V (ORCPT ); Thu, 22 Mar 2018 12:27:21 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:33784 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750863AbeCVQ1A (ORCPT ); Thu, 22 Mar 2018 12:27:00 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 68B8060FAA; Thu, 22 Mar 2018 16:27:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521736020; bh=Jj252tKfFiUlujy4nF346mRqQD7UDy1fxoQggXsRcYQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ocuU2luLZjrG++bDnPnZIQBsOQwDxHFrr/5FCkpjR8RO28hCKykczoAFH6Fk4eRTF 5C7odcXjFCQcHTaFA8xZKCJfFQnWmbiH5e29YnrEh0HaD/WT8d90NeO5IoukxsGRas lPmCdlVkkgmfCzfCSnE9ULI5jExlXUTA1qBsW3QY= 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 8331760F6C; Thu, 22 Mar 2018 16:26:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521736019; bh=Jj252tKfFiUlujy4nF346mRqQD7UDy1fxoQggXsRcYQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NyUSBJg6Pd0+FhUqgztGtZnvu+jduF/OwqyZCiLCheKcxfravHuX2dizk0eiqL0kY J8xZG9LLx69VUIMCRjvJrR2Nf7vXta2LU5tLNzDuzSSEr7bqxY+v2tIF0tqHPgZswA J3XcZ1oRpP3ua/jAsSSfR+g5HPs33ewb30s01+j8= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 8331760F6C 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 v5 3/3] RDMA/qedr: eliminate duplicate barriers on weakly-ordered archs #2 Date: Thu, 22 Mar 2018 12:26:49 -0400 Message-Id: <1521736009-23387-4-git-send-email-okaya@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1521736009-23387-1-git-send-email-okaya@codeaurora.org> References: <1521736009-23387-1-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 --- 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..d6bd950 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();