From patchwork Wed Mar 14 03:20:22 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sinan Kaya X-Patchwork-Id: 10281377 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 3525560231 for ; Wed, 14 Mar 2018 03:20:53 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 237C22866D for ; Wed, 14 Mar 2018 03:20:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 15F502866F; Wed, 14 Mar 2018 03:20:53 +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=-1.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 9332F28662 for ; Wed, 14 Mar 2018 03:20:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject:To :From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=5TujYKea8PRnJZUV7CexqALPA4lUW2Pm8khz8W/WRsc=; b=W5hTC37iew6HPY Llaq2nNX0FGET/xEHOLKiNQ+pB9OewCTSJIuLMz+NFDgRcnqivEbpEPZ46oziJeUvq25DAhkBiHRJ 8dtzr0UP3/So+6pm9WAzlKoawxDQIZABI70xW5+JjMhty/w41kiLtc1XR49kgNVv1idniSM1p6wvG ijVQjyAkrVVkTyDxMZLsOr8PS1CgkpEAtozoLteL7MGaWooCrxczNHrBCol1zVVgf0ci4sjiwpTwG NLZgZdoyE3gvZe0WF4EgVUatphGehIe0R791sYZZD0nNX395/n1LhGZ4nxWkFA74GEqYLJ4ugzeF3 S957syB49O/U7qO6QeuQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1evwy3-0003uZ-3D; Wed, 14 Mar 2018 03:20:43 +0000 Received: from smtp.codeaurora.org ([198.145.29.96]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1evwxz-0003sI-5q for linux-arm-kernel@lists.infradead.org; Wed, 14 Mar 2018 03:20:40 +0000 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 00DDD6084A; Wed, 14 Mar 2018 03:20:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1520997636; bh=zqEDc5+sVTJuqPfrwG2GU85GD5muqnwKbTmbuxIGE+Y=; h=From:To:Cc:Subject:Date:From; b=fM27kAQqjjIgTGNSe+Ogd58ixH+xCFjMHqfIghkm8/ZPX0IfWfDACM7rhmL+WxK7e +/47Wvybto1Ny0T6hvtSEXKl6+JmdqYLd/geHPx40qDWL0SB3Y9hE0w7y+J1oaw/g5 007DIUOJR/eEx5QaDHZjAW7E1eLK3tI+EjfoIhjg= 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 8142F607A2; Wed, 14 Mar 2018 03:20:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1520997635; bh=zqEDc5+sVTJuqPfrwG2GU85GD5muqnwKbTmbuxIGE+Y=; h=From:To:Cc:Subject:Date:From; b=iK1k1KLmr6OdDgzdNXBW1z/H9i7ewYbt1TKlgYE+TfIi5FRkcA0j1JDw1l54rKqOY nWpuCtTv2Gdr6pmR7KsgjVkqLh6cB6UOrZA8ogW2Pa5GtiMP55zL/Dn+xOZo5YraJj qAYHRFLek6ztJo0jp33Dwipi64tUY1aogbueTDhM= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 8142F607A2 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 Subject: [PATCH 1/7] i40e/i40evf: Eliminate duplicate barriers on weakly-ordered archs Date: Tue, 13 Mar 2018 23:20:22 -0400 Message-Id: <1520997629-17361-1-git-send-email-okaya@codeaurora.org> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180313_202039_273825_7D177253 X-CRM114-Status: GOOD ( 11.69 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, Sinan Kaya , intel-wired-lan@lists.osuosl.org, Jeff Kirsher , linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.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 --- drivers/net/ethernet/intel/i40e/i40e_txrx.c | 2 +- drivers/net/ethernet/intel/i40evf/i40e_txrx.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c index e554aa6cf..7028516 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c @@ -1375,7 +1375,7 @@ static inline void i40e_release_rx_desc(struct i40e_ring *rx_ring, u32 val) * such as IA-64). */ wmb(); - writel(val, rx_ring->tail); + writel_relaxed(val, rx_ring->tail); } /** diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c index 357d605..2d323fc 100644 --- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c @@ -667,7 +667,7 @@ static inline void i40e_release_rx_desc(struct i40e_ring *rx_ring, u32 val) * such as IA-64). */ wmb(); - writel(val, rx_ring->tail); + writel_relaxed(val, rx_ring->tail); } /**