From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sinan Kaya 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> References: <1520997629-17361-1-git-send-email-okaya@codeaurora.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1520997629-17361-1-git-send-email-okaya@codeaurora.org> Sender: linux-kernel-owner@vger.kernel.org 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 List-Id: linux-arm-msm@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/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); } } -- 2.7.4