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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 2A823C433DB for ; Tue, 16 Mar 2021 08:12:09 +0000 (UTC) Received: from smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (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 BC2B264FC2 for ; Tue, 16 Mar 2021 08:12:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BC2B264FC2 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 smtp1.osuosl.org (Postfix) with ESMTP id 83F6E83A82; Tue, 16 Mar 2021 08:12:08 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 4fUD4GE5LgBi; Tue, 16 Mar 2021 08:12:07 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp1.osuosl.org (Postfix) with ESMTP id 80D4083A80; Tue, 16 Mar 2021 08:12:07 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 6C542C000C; Tue, 16 Mar 2021 08:12:07 +0000 (UTC) Received: from smtp4.osuosl.org (smtp4.osuosl.org [IPv6:2605:bc80:3010::137]) by lists.linuxfoundation.org (Postfix) with ESMTP id 7674CC000A for ; Tue, 16 Mar 2021 08:12:06 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id 572184EC34 for ; Tue, 16 Mar 2021 08:12:06 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 9MbV6B3uOTHA for ; Tue, 16 Mar 2021 08:12:04 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.8.0 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by smtp4.osuosl.org (Postfix) with ESMTPS id 416034CE53 for ; Tue, 16 Mar 2021 08:12:04 +0000 (UTC) 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 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) Cc: Minturn Dave B , Matthew Wilcox , Jason Gunthorpe , linux-pci@vger.kernel.org, Daniel Vetter , Dave Hansen , Ira Weiny , linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, Stephen Bates , linux-block@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, Christian =?iso-8859-1?Q?K=F6nig?= , Jason Ekstrand , John Hubbard , Dan Williams , Jakowski Andrzej , Christoph Hellwig , Xiong Jianxin 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, 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. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu