From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EBEFEC43461 for ; Thu, 3 Sep 2020 08:46:53 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B8573206EB for ; Thu, 3 Sep 2020 08:46:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B8573206EB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id 8E76786C2F; Thu, 3 Sep 2020 08:46:53 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id BSfFsqVaKP4P; Thu, 3 Sep 2020 08:46:50 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by fraxinus.osuosl.org (Postfix) with ESMTP id EB48C86BFE; Thu, 3 Sep 2020 08:46:50 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id D6B10C07FF; Thu, 3 Sep 2020 08:46:50 +0000 (UTC) Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) by lists.linuxfoundation.org (Postfix) with ESMTP id 57DA7C0051 for ; Thu, 3 Sep 2020 08:46:49 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by whitealder.osuosl.org (Postfix) with ESMTP id 54C0D86B0B for ; Thu, 3 Sep 2020 08:46:49 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id OH-rTxrpAUc5 for ; Thu, 3 Sep 2020 08:46:48 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by whitealder.osuosl.org (Postfix) with ESMTPS id 1FA1A86B0A for ; Thu, 3 Sep 2020 08:46:48 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id F0C1868CEE; Thu, 3 Sep 2020 10:46:43 +0200 (CEST) Date: Thu, 3 Sep 2020 10:46:43 +0200 From: Christoph Hellwig To: Thomas Bogendoerfer Subject: Re: [PATCH 22/28] sgiseeq: convert from dma_cache_sync to dma_sync_single_for_device Message-ID: <20200903084643.GA25111@lst.de> References: <20200819065555.1802761-1-hch@lst.de> <20200819065555.1802761-23-hch@lst.de> <20200901152209.GA14288@alpha.franken.de> <20200901171241.GA20685@alpha.franken.de> <20200901171627.GA8255@lst.de> <20200901173810.GA25282@alpha.franken.de> <20200903084302.GB24410@lst.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200903084302.GB24410@lst.de> User-Agent: Mutt/1.5.17 (2007-11-01) Cc: alsa-devel@alsa-project.org, linux-ia64@vger.kernel.org, linux-doc@vger.kernel.org, nouveau@lists.freedesktop.org, linux-nvme@lists.infradead.org, linux-mips@vger.kernel.org, "James E.J. Bottomley" , linux-mm@kvack.org, Christoph Hellwig , linux-samsung-soc@vger.kernel.org, Joonyoung Shim , linux-scsi@vger.kernel.org, iommu@lists.linux-foundation.org, Ben Skeggs , Matt Porter , linux-media@vger.kernel.org, Tom Lendacky , Pawel Osciak , Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, linux-parisc@vger.kernel.org, netdev@vger.kernel.org, Seung-Woo Kim , linux-kernel@vger.kernel.org, Kyungmin Park X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Thu, Sep 03, 2020 at 10:43:02AM +0200, Christoph Hellwig wrote: > On Tue, Sep 01, 2020 at 07:38:10PM +0200, Thomas Bogendoerfer wrote: > > this is the problem: > > > > /* Always check for received packets. */ > > sgiseeq_rx(dev, sp, hregs, sregs); > > > > so the driver will look at the rx descriptor on every interrupt, so > > we cache the rx descriptor on the first interrupt and if there was > > $no rx packet, we will only see it, if cache line gets flushed for > > some other reason. > > That means a transfer back to device ownership is missing after a > (negative) check. E.g. something like this for the particular problem, although there might be other hiding elsewhere: diff --git a/drivers/net/ethernet/seeq/sgiseeq.c b/drivers/net/ethernet/seeq/sgiseeq.c index 8507ff2420143a..a1c7be8a0d1e5d 100644 --- a/drivers/net/ethernet/seeq/sgiseeq.c +++ b/drivers/net/ethernet/seeq/sgiseeq.c @@ -403,6 +403,8 @@ static inline void sgiseeq_rx(struct net_device *dev, struct sgiseeq_private *sp rd = &sp->rx_desc[sp->rx_new]; dma_sync_desc_cpu(dev, rd); } + dma_sync_desc_dev(dev, rd); + dma_sync_desc_cpu(dev, &sp->rx_desc[orig_end]); sp->rx_desc[orig_end].rdma.cntinfo &= ~(HPCDMA_EOR); dma_sync_desc_dev(dev, &sp->rx_desc[orig_end]); _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu