From patchwork Fri Mar 23 18:21:15 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sinan Kaya X-Patchwork-Id: 10305327 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 CDE1460384 for ; Fri, 23 Mar 2018 18:23:34 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BD0AE29072 for ; Fri, 23 Mar 2018 18:23:34 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B1E622907D; Fri, 23 Mar 2018 18:23:34 +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=ham 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 7C5D229072 for ; Fri, 23 Mar 2018 18:23:33 +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=rC9BieBmGpAGPpjKQbUxzWf3Ou7RotB+M6jtaWXWtTs=; b=jqbevN98lepOfe G/pLfpBJYmxieIXM5tK3C10Cy8CGz5PHd/BofbQ5HjF8AGTuLY+KsVm8xcN/BuVCjEsiZILzzpsiW CyNZ17kmAi4h+DuiC2cWV2W5Ro8O9WX9m0NzdEm4DhGC8N1eAzmoyStpiSrz6xp0G7oV3QLOSSJMW PV3LHrziuSLSLZHOE2lu6qLvc41Qw0qOym04j0S3yioHNZHmtWmLeW86J0crf5RC4e/xWsgNmTG3d GthbbMwSIdXLOzlFU7qd+NXxk4hKqFkraOANaovHjbwR9WuKu4sDtlI9W57/ms9ffGt9gStnC0LM1 SZVAQ+Vi7Hq7MitPTnEg==; 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 1ezRLZ-0008M9-TQ; Fri, 23 Mar 2018 18:23:25 +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 1ezRK0-0007Mh-Bj for linux-arm-kernel@lists.infradead.org; Fri, 23 Mar 2018 18:22:00 +0000 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 98F0460F5C; Fri, 23 Mar 2018 18:21:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521829293; bh=Mhz5L9FTFCe5KrTBsorzJ3OrDTzmNUN7NCUhoaDOdPE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aa5g/b4A1JEssbntPbaSGSNYZDJIpYo4sCp/w2JUlqRbe2+KaV2XEg+TnXPYGCM6/ E6bDqPm+LUmARDHHpoO2D4lfgLOcCH0POpBrFCEgPsifmur/4qKwHc6kJ7gqVNi6Ye DWCmhP5C+xxfLcqHz3/E0u6kdG9D/Qz1IogM6/tE= 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 D735460F8E; Fri, 23 Mar 2018 18:21:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521829291; bh=Mhz5L9FTFCe5KrTBsorzJ3OrDTzmNUN7NCUhoaDOdPE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MqfzjWPw1HZem8ZZcgYuMdDKsdqKSxaHaB+QEKEiB0a6BSsu7j+747Qag9oKjjd4G Jawt04EU/mpcTGH2HXKQW8O0mhQMZcpZXzu3Y4jbUA8QnOksNKPZEbyo9JB3ZpzKJi nyiVOJMuI5tMl6Zqtle7sAfxVJUkRhmdMV6dOiU4= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org D735460F8E 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: jeffrey.t.kirsher@intel.com Subject: [PATCH v6 5/7] fm10k: Eliminate duplicate barriers on weakly-ordered archs Date: Fri, 23 Mar 2018 14:21:15 -0400 Message-Id: <1521829277-9398-6-git-send-email-okaya@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1521829277-9398-1-git-send-email-okaya@codeaurora.org> References: <1521829277-9398-1-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-20180323_112149_286886_FDDF33B5 X-CRM114-Status: GOOD ( 12.86 ) 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: sulrich@codeaurora.org, netdev@vger.kernel.org, timur@codeaurora.org, linux-kernel@vger.kernel.org, Sinan Kaya , intel-wired-lan@lists.osuosl.org, linux-arm-msm@vger.kernel.org, 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/fm10k/fm10k_main.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_main.c b/drivers/net/ethernet/intel/fm10k/fm10k_main.c index 409554d..360ff9b 100644 --- a/drivers/net/ethernet/intel/fm10k/fm10k_main.c +++ b/drivers/net/ethernet/intel/fm10k/fm10k_main.c @@ -180,7 +180,12 @@ void fm10k_alloc_rx_buffers(struct fm10k_ring *rx_ring, u16 cleaned_count) wmb(); /* notify hardware of new descriptors */ - writel(i, rx_ring->tail); + writel_relaxed(i, rx_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 + */ + mmiowb(); } } @@ -1055,7 +1060,7 @@ static void fm10k_tx_map(struct fm10k_ring *tx_ring, /* 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