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Wed, 14 Mar 2018 03:20:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1520997643; bh=ka8d+sT21K8+IXcE+cWsjS54nGzKj2ZImZ7FtVdRJzA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZaAoybOcfcXDudn3l4rK/WTsFv80md9V04DjOP2vnZDy8Ay3sABfAQYQL9mmNNnt0 up/KQA2A8Lm/sJedsvl1VNW3zGwgi/7LEFwHHlXsUwgcr6HTb4+MrC4Bgq66JGWE27 ypn/rTsmrxRpHEeHdZDZ8vBo5hu6kNXgzFmZN5Ok= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 4514460867 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 6/7] e1000: eliminate duplicate barriers on weakly-ordered archs Date: Tue, 13 Mar 2018 23:20:27 -0400 Message-Id: <1520997629-17361-6-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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180313_202049_197769_EE68A652 X-CRM114-Status: GOOD ( 12.01 ) 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/e1000/e1000_main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c b/drivers/net/ethernet/intel/e1000/e1000_main.c index 3dd4aeb..e0e583a 100644 --- a/drivers/net/ethernet/intel/e1000/e1000_main.c +++ b/drivers/net/ethernet/intel/e1000/e1000_main.c @@ -4573,7 +4573,7 @@ e1000_alloc_jumbo_rx_buffers(struct e1000_adapter *adapter, * such as IA-64). */ wmb(); - writel(i, adapter->hw.hw_addr + rx_ring->rdt); + writel_relaxed(i, adapter->hw.hw_addr + rx_ring->rdt); } } @@ -4688,7 +4688,7 @@ static void e1000_alloc_rx_buffers(struct e1000_adapter *adapter, * such as IA-64). */ wmb(); - writel(i, hw->hw_addr + rx_ring->rdt); + writel_relaxed(i, hw->hw_addr + rx_ring->rdt); } }