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Fri, 16 Mar 2018 16:16:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521217018; bh=aNMVva350+N/hb+Ml551XcOdMcW0iW4A33zVL7SZ1Xo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PcZXt83ZMg6pm0UCdPxYME7anb7SC8yPoZjlfPe22kjnPIe6nPDb/PdX7nDAEpBKQ swDGS+h5nAfnyfyiCFi13Z6CoFSMWm8ids9EvYWnKCybcnhxcwAKif0C9aH4mIyElj ONcFdlS9yGquSRCLdm/baxfwYUfuVghYFJd35zfM= 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 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180316_121710_294095_8D5C1179 X-CRM114-Status: GOOD ( 14.12 ) 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: Kees Cook , Johannes Berg , linux-arm-msm@vger.kernel.org, Allen Pais , linux-kernel@vger.kernel.org, Sinan Kaya , "David S. Miller" , 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/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); } /*