From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934777AbeCPQRL (ORCPT ); Fri, 16 Mar 2018 12:17:11 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:39570 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754636AbeCPQRD (ORCPT ); Fri, 16 Mar 2018 12:17:03 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 2B41760C64 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 v3 09/18] fm10k: Eliminate duplicate barriers on weakly-ordered archs Date: Fri, 16 Mar 2018 12:16:22 -0400 Message-Id: <1521216991-28706-10-git-send-email-okaya@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1521216991-28706-1-git-send-email-okaya@codeaurora.org> References: <1521216991-28706-1-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(). 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/fm10k/fm10k_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_main.c b/drivers/net/ethernet/intel/fm10k/fm10k_main.c index 8e12aae..8d04e26 100644 --- a/drivers/net/ethernet/intel/fm10k/fm10k_main.c +++ b/drivers/net/ethernet/intel/fm10k/fm10k_main.c @@ -179,7 +179,7 @@ void fm10k_alloc_rx_buffers(struct fm10k_ring *rx_ring, u16 cleaned_count) wmb(); /* notify hardware of new descriptors */ - writel(i, rx_ring->tail); + writel_relaxed(i, rx_ring->tail); } } -- 2.7.4