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=-5.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 1F722C433E0 for ; Tue, 16 Mar 2021 08:12:22 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 C4CCE64FC4 for ; Tue, 16 Mar 2021 08:12:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C4CCE64FC4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=0sI9fZDhGkXlOMJXbkA5KEfDJk4E42C8WHjyLFY95VA=; b=c+9r1mivSAocuAmYR+J1wwSvK g6EMFv+9EJjc1qjq5cQu510l+3DheyDKCkFJbnZkl+zVQ1khN3ir0+dMCqPQWr5c6Sn+qRJ4uL9Tc HR5PUh8VotiC5bVym1Eo+Y4MsI0GzP9JVuz+jBHU8uv9As/dRcD1V/I+OXqFq1uQnbOd3yCyW0kOV u/F/xfl7/fYEigb27cSe3Owwv32ykIiBpniCenuOFr+ozaGqonLIU57vqBatWbr+yHK+93PdQ7PGy TvYf2Qxxo+kjDPCjTnOhrJ15hAUyRCw+RCZcRKLMMhb3w4ii5tGG+fRgyQUI6sggiNlpbqD6w39iH 0GtmU4msA==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lM4oB-00078x-Lr; Tue, 16 Mar 2021 08:12:07 +0000 Received: from verein.lst.de ([213.95.11.211]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lM4o6-00077Z-Nn for linux-nvme@lists.infradead.org; Tue, 16 Mar 2021 08:12:05 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 68EB168C4E; Tue, 16 Mar 2021 09:11:57 +0100 (CET) Date: Tue, 16 Mar 2021 09:11:56 +0100 From: Christoph Hellwig To: Logan Gunthorpe Cc: linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, Stephen Bates , Christoph Hellwig , Dan Williams , Jason Gunthorpe , Christian =?iso-8859-1?Q?K=F6nig?= , Ira Weiny , John Hubbard , Don Dutile , Matthew Wilcox , Daniel Vetter , Jakowski Andrzej , Minturn Dave B , Jason Ekstrand , Dave Hansen , Xiong Jianxin Subject: Re: [RFC PATCH v2 06/11] dma-direct: Support PCI P2PDMA pages in dma-direct map_sg Message-ID: <20210316081156.GA16595@lst.de> References: <20210311233142.7900-1-logang@deltatee.com> <20210311233142.7900-7-logang@deltatee.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210311233142.7900-7-logang@deltatee.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210316_081203_846098_5EC67381 X-CRM114-Status: GOOD ( 14.73 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Thu, Mar 11, 2021 at 04:31:36PM -0700, Logan Gunthorpe wrote: > for_each_sg(sgl, sg, nents, i) { > + if (is_pci_p2pdma_page(sg_page(sg))) { > + if (sg_page(sg)->pgmap != pgmap) { > + pgmap = sg_page(sg)->pgmap; > + map = pci_p2pdma_dma_map_type(dev, pgmap); > + bus_off = pci_p2pdma_bus_offset(sg_page(sg)); > + } > + > + if (map < 0) { > + sg->dma_address = DMA_MAPPING_ERROR; > + ret = -EREMOTEIO; > + goto out_unmap; > + } > + > + if (map) { > + sg->dma_address = sg_phys(sg) + sg->offset - > + bus_off; > + sg_dma_len(sg) = sg->length; > + sg_mark_pci_p2pdma(sg); > + continue; > + } > + } This code needs to go into a separate noinline helper to reduce the impact on the fast path. Also as Robin noted the offset is already accounted for in sg_phys. We also don't ever set the dma_address in the scatterlist to DMA_MAPPING_ERROR, that is just a return value for the single entry mapping routines. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme