From patchwork Fri Mar 16 16:16:14 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sinan Kaya X-Patchwork-Id: 10290459 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 536426061F for ; Fri, 16 Mar 2018 23:00:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 47288290EB for ; Fri, 16 Mar 2018 23:00:48 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3BFA5290EE; Fri, 16 Mar 2018 23:00:48 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id C17E9290EB for ; Fri, 16 Mar 2018 23:00:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=JUrJyjtUQpyF+T5Y8PS6FfN5VCrT8/58E9Q75Z6IrO4=; b=el9XKkBXgRH5Xc CGi5Csmf31cJgqnuqFjGl2Ntx8JwRcBbIEEdaXbFddQPRSzdMlEbn20SsBgKChZy6exw9l63aWHSl B2xK3vrX+E/jooQ90OdmD9HGnzCoH94qt269duanOIiK4hIEMZWNwmqTvkSwAD84E7FOWcMoH3bUK sKXSYkRI9j3mTp2JuY39TBH9fYeZlmArn0bBqpBU4YSDgfOzwMnSlPDpd/v2h08ZQplWiSKYh5ioV Ik/GDu31PEme73ldWA7dNtCaFtZcrV8bBnG/rRvpS0B7zI9BBqLs53tfNMiu+U04yeKJ1KhCRHrKU WEgb6sr6UmapLFusGmKw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1ewyL0-0003U3-Mu; Fri, 16 Mar 2018 23:00:38 +0000 Received: from smtp.codeaurora.org ([198.145.29.96]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1ews2L-0006Xq-DV for linux-arm-kernel@lists.infradead.org; Fri, 16 Mar 2018 16:17:24 +0000 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 7BDCB6030F; Fri, 16 Mar 2018 16:16:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521217006; bh=xs1ZZO9n0C4/ROi31FCgjykWH9oPGVohsy+fHK8fZms=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=G6ngUPFs4t+VGGHsjm9ZtuZ7v+m3TgRf8zj4qjzPqpordzjv0L4PeVIsGnCsPFks6 q2lXobS3lIdhnfqfs61E6OOc4w/0h979nj0Pput5fzmaFTGfkY0XsLf4Ekk3tzybNx AtmuYcknSJRBcESMP+IxX5mUZfbKSXotJ0ESX7JU= Received: from drakthul.qualcomm.com (global_nat1_iad_fw.qualcomm.com [129.46.232.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: okaya@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 2BB1A60390; Fri, 16 Mar 2018 16:16:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521217006; bh=xs1ZZO9n0C4/ROi31FCgjykWH9oPGVohsy+fHK8fZms=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=G6ngUPFs4t+VGGHsjm9ZtuZ7v+m3TgRf8zj4qjzPqpordzjv0L4PeVIsGnCsPFks6 q2lXobS3lIdhnfqfs61E6OOc4w/0h979nj0Pput5fzmaFTGfkY0XsLf4Ekk3tzybNx AtmuYcknSJRBcESMP+IxX5mUZfbKSXotJ0ESX7JU= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 2BB1A60390 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 01/18] i40e/i40evf: Eliminate duplicate barriers on weakly-ordered archs Date: Fri, 16 Mar 2018 12:16:14 -0400 Message-Id: <1521216991-28706-2-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_410428_BC929C72 X-CRM114-Status: GOOD ( 12.63 ) 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/i40e/i40e_txrx.c | 8 ++++---- drivers/net/ethernet/intel/i40evf/i40e_txrx.c | 4 ++-- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c index e554aa6cf..9455869 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c @@ -185,7 +185,7 @@ static int i40e_program_fdir_filter(struct i40e_fdir_filter *fdir_data, /* Mark the data descriptor to be watched */ first->next_to_watch = tx_desc; - writel(tx_ring->next_to_use, tx_ring->tail); + writel_relaxed(tx_ring->next_to_use, tx_ring->tail); return 0; dma_fail: @@ -1375,7 +1375,7 @@ static inline void i40e_release_rx_desc(struct i40e_ring *rx_ring, u32 val) * such as IA-64). */ wmb(); - writel(val, rx_ring->tail); + writel_relaxed(val, rx_ring->tail); } /** @@ -2258,7 +2258,7 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget) */ wmb(); - writel(xdp_ring->next_to_use, xdp_ring->tail); + writel_relaxed(xdp_ring->next_to_use, xdp_ring->tail); } rx_ring->skb = skb; @@ -3286,7 +3286,7 @@ static inline int i40e_tx_map(struct i40e_ring *tx_ring, struct sk_buff *skb, /* notify HW of packet */ if (netif_xmit_stopped(txring_txq(tx_ring)) || !skb->xmit_more) { - writel(i, tx_ring->tail); + writel_relaxed(i, tx_ring->tail); /* we need this if more than one processor can write to our tail * at a time, it synchronizes IO on IA64/Altix systems diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c index 357d605..56eea20 100644 --- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c @@ -667,7 +667,7 @@ static inline void i40e_release_rx_desc(struct i40e_ring *rx_ring, u32 val) * such as IA-64). */ wmb(); - writel(val, rx_ring->tail); + writel_relaxed(val, rx_ring->tail); } /** @@ -2243,7 +2243,7 @@ static inline void i40evf_tx_map(struct i40e_ring *tx_ring, struct sk_buff *skb, /* notify HW of packet */ if (netif_xmit_stopped(txring_txq(tx_ring)) || !skb->xmit_more) { - writel(i, tx_ring->tail); + writel_relaxed(i, tx_ring->tail); /* we need this if more than one processor can write to our tail * at a time, it synchronizes IO on IA64/Altix systems