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[209.132.180.67]) by mx.google.com with ESMTP id x1-v6si1216512plb.248.2018.03.13.20.23.46; Tue, 13 Mar 2018 20:24:00 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@codeaurora.org header.s=default header.b=C2FM2NSj; dkim=pass header.i=@codeaurora.org header.s=default header.b=C2FM2NSj; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933551AbeCNDW2 (ORCPT + 99 others); Tue, 13 Mar 2018 23:22:28 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:43162 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933316AbeCNDUi (ORCPT ); Tue, 13 Mar 2018 23:20:38 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 9B112607A2; Wed, 14 Mar 2018 03:20:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1520997637; bh=wb9xtlCktc5g3rJH4kmsb3V4Ftg8s5ceqodGJJolQjQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=C2FM2NSj8sh+zKlqfcIzdm5ZQD2wgxtOCUpzldh49OMY/0KG73A8FjVyVlmnJByt7 c/2uPQfCcFDlM8ftiqryEghbugZlQZUI3T/j9E8yU964omceTMboS9dfQbfwIh2dO+ IZuI6ihm/QvfWFqST8GX1qh1IG49IfY2+N4YvFiY= X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on pdx-caf-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.8 required=2.0 tests=ALL_TRUSTED,BAYES_00, DKIM_SIGNED,T_DKIM_INVALID autolearn=no autolearn_force=no version=3.4.0 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 27EE0607A2; Wed, 14 Mar 2018 03:20:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1520997637; bh=wb9xtlCktc5g3rJH4kmsb3V4Ftg8s5ceqodGJJolQjQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=C2FM2NSj8sh+zKlqfcIzdm5ZQD2wgxtOCUpzldh49OMY/0KG73A8FjVyVlmnJByt7 c/2uPQfCcFDlM8ftiqryEghbugZlQZUI3T/j9E8yU964omceTMboS9dfQbfwIh2dO+ IZuI6ihm/QvfWFqST8GX1qh1IG49IfY2+N4YvFiY= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 27EE0607A2 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 , Jeff Kirsher , intel-wired-lan@lists.osuosl.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/7] ixgbe: eliminate duplicate barriers on weakly-ordered archs Date: Tue, 13 Mar 2018 23:20:23 -0400 Message-Id: <1520997629-17361-2-git-send-email-okaya@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1520997629-17361-1-git-send-email-okaya@codeaurora.org> References: <1520997629-17361-1-git-send-email-okaya@codeaurora.org> MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk 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/net/ethernet/intel/ixgbe/ixgbe_main.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c index 0da5aa2..35ca1d8 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c @@ -1692,7 +1692,7 @@ void ixgbe_alloc_rx_buffers(struct ixgbe_ring *rx_ring, u16 cleaned_count) * such as IA-64). */ wmb(); - writel(i, rx_ring->tail); + writel_relaxed(i, rx_ring->tail); } } @@ -2453,7 +2453,7 @@ static int ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector, * know there are new descriptors to fetch. */ wmb(); - writel(ring->next_to_use, ring->tail); + writel_relaxed(ring->next_to_use, ring->tail); xdp_do_flush_map(); } @@ -10014,7 +10014,7 @@ static void ixgbe_xdp_flush(struct net_device *dev) * are new descriptors to fetch. */ wmb(); - writel(ring->next_to_use, ring->tail); + writel_relaxed(ring->next_to_use, ring->tail); return; } -- 2.7.4