From patchwork Sun Mar 25 14:39:19 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sinan Kaya X-Patchwork-Id: 10306655 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 62927600F6 for ; Sun, 25 Mar 2018 14:41:33 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 51020281B7 for ; Sun, 25 Mar 2018 14:41:33 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 458F828C63; Sun, 25 Mar 2018 14:41:33 +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 DB1A0281B7 for ; Sun, 25 Mar 2018 14:41:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753662AbeCYOlb (ORCPT ); Sun, 25 Mar 2018 10:41:31 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:59366 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753408AbeCYOjf (ORCPT ); Sun, 25 Mar 2018 10:39:35 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 5F978606DB; Sun, 25 Mar 2018 14:39:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521988774; bh=xihGvyzCn0WEEWLaeWipjVki0XnjkkU5lFTxK257S4I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OX4QAFLiUESVICFfjNmSEYR96/z1tcozrAN8tXmGBReaQLF85cLshpK6x59ixKWhN lVAahCn3FsHavG3QTuBfwHqZKERmCZo5q4qBEPV82nc13/UvaLrPYrsI8IqEOfHTfa nThgY9FfEt3mEBLeNE8RoDR/hdgONLP0eqQp7SDg= 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 DD32C60F6D; Sun, 25 Mar 2018 14:39:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521988773; bh=xihGvyzCn0WEEWLaeWipjVki0XnjkkU5lFTxK257S4I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CSnALv5ldNFkUg6DtGGXL8FfhvxZ8X9rrCdGgfOknXUsSGm22u154b3NRFm6XPudl 95QL/HlxcyrMeyO+yzUstOW3bZeWw2GTq7Wpn+E1vKJYW8rHX409uJ8j9d82Th+jzB yo5G3zAtUUtcJEp/36FnmfUdRHY+Ck5VTqD81cpU= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org DD32C60F6D 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 , Harish Patil , Manish Chopra , Dept-GELinuxNICDev@cavium.com, linux-kernel@vger.kernel.org Subject: [PATCH v7 5/7] net: qlge: Eliminate duplicate barriers on weakly-ordered archs Date: Sun, 25 Mar 2018 10:39:19 -0400 Message-Id: <1521988761-30344-6-git-send-email-okaya@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1521988761-30344-1-git-send-email-okaya@codeaurora.org> References: <1521988761-30344-1-git-send-email-okaya@codeaurora.org> MIME-Version: 1.0 Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@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. Create a new wrapper function with relaxed write operator. Use the new wrapper when a write is following a wmb(). Signed-off-by: Sinan Kaya --- drivers/net/ethernet/qlogic/qlge/qlge.h | 16 ++++++++++++++++ drivers/net/ethernet/qlogic/qlge/qlge_main.c | 3 ++- 2 files changed, 18 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/qlogic/qlge/qlge.h b/drivers/net/ethernet/qlogic/qlge/qlge.h index 84ac50f..3e71b65 100644 --- a/drivers/net/ethernet/qlogic/qlge/qlge.h +++ b/drivers/net/ethernet/qlogic/qlge/qlge.h @@ -2185,6 +2185,22 @@ static inline void ql_write_db_reg(u32 val, void __iomem *addr) } /* + * Doorbell Registers: + * Doorbell registers are virtual registers in the PCI memory space. + * The space is allocated by the chip during PCI initialization. The + * device driver finds the doorbell address in BAR 3 in PCI config space. + * The registers are used to control outbound and inbound queues. For + * example, the producer index for an outbound queue. Each queue uses + * 1 4k chunk of memory. The lower half of the space is for outbound + * queues. The upper half is for inbound queues. + * Caller has to guarantee ordering. + */ +static inline void ql_write_db_reg_relaxed(u32 val, void __iomem *addr) +{ + writel_relaxed(val, addr); +} + +/* * Shadow Registers: * Outbound queues have a consumer index that is maintained by the chip. * Inbound queues have a producer index that is maintained by the chip. diff --git a/drivers/net/ethernet/qlogic/qlge/qlge_main.c b/drivers/net/ethernet/qlogic/qlge/qlge_main.c index 50038d9..8293c202 100644 --- a/drivers/net/ethernet/qlogic/qlge/qlge_main.c +++ b/drivers/net/ethernet/qlogic/qlge/qlge_main.c @@ -2700,7 +2700,8 @@ static netdev_tx_t qlge_send(struct sk_buff *skb, struct net_device *ndev) tx_ring->prod_idx = 0; wmb(); - ql_write_db_reg(tx_ring->prod_idx, tx_ring->prod_idx_db_reg); + ql_write_db_reg_relaxed(tx_ring->prod_idx, tx_ring->prod_idx_db_reg); + mmiowb(); netif_printk(qdev, tx_queued, KERN_DEBUG, qdev->ndev, "tx queued, slot %d, len %d\n", tx_ring->prod_idx, skb->len);