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Fri, 16 Mar 2018 16:16:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521217013; bh=i73Sp+KUBO8eECEu13WF8HxhmVlcrS32Xt4J3/QhqqM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=j25ysh4Dp0tBhhsqjHx/oG/8g7m9q+ca+DH4UL+9jpvVSzDoftcMOv4E+Pe2kZxZm +ldGdhbPLdEHK7GNja6qWpwv0u4FRTWLO7+bYyzG6fPlrhT8GM9HM00aDZY8U9BYf9 +kBwNs2wcWiO2I/EuWX49bCjXmPNjWgZxdJOCXFk= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 78C38603AF 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 06/18] ixgbevf: eliminate duplicate barriers on weakly-ordered archs Date: Fri, 16 Mar 2018 12:16:19 -0400 Message-Id: <1521216991-28706-7-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_091658_780012_EA57C867 X-CRM114-Status: GOOD ( 12.31 ) 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() 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/ixgbevf/ixgbevf_main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c index 6bf778a..774b2a6 100644 --- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c +++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c @@ -659,7 +659,7 @@ static void ixgbevf_alloc_rx_buffers(struct ixgbevf_ring *rx_ring, * such as IA-64). */ wmb(); - writel(i, rx_ring->tail); + writel_relaxed(i, rx_ring->tail); } } @@ -3644,7 +3644,7 @@ static void ixgbevf_tx_map(struct ixgbevf_ring *tx_ring, tx_ring->next_to_use = i; /* notify HW of packet */ - writel(i, tx_ring->tail); + writel_relaxed(i, tx_ring->tail); return; dma_error: