From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934758AbeCPQRJ (ORCPT ); Fri, 16 Mar 2018 12:17:09 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:39442 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754347AbeCPQRA (ORCPT ); Fri, 16 Mar 2018 12:17:00 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org BECDB60390 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 , "David S. Miller" , Kees Cook , Johannes Berg , Allen Pais , linux-kernel@vger.kernel.org Subject: [PATCH v3 07/18] drivers: net: cxgb: Eliminate duplicate barriers on weakly-ordered archs Date: Fri, 16 Mar 2018 12:16:20 -0400 Message-Id: <1521216991-28706-8-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/chelsio/cxgb/sge.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/chelsio/cxgb/sge.c b/drivers/net/ethernet/chelsio/cxgb/sge.c index 30de26e..57891bd6 100644 --- a/drivers/net/ethernet/chelsio/cxgb/sge.c +++ b/drivers/net/ethernet/chelsio/cxgb/sge.c @@ -495,7 +495,7 @@ static struct sk_buff *sched_skb(struct sge *sge, struct sk_buff *skb, static inline void doorbell_pio(struct adapter *adapter, u32 val) { wmb(); - writel(val, adapter->regs + A_SG_DOORBELL); + writel_relaxed(val, adapter->regs + A_SG_DOORBELL); } /* -- 2.7.4