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=-12.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,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 80A50C433B4 for ; Fri, 14 May 2021 16:17:59 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 21A9161353 for ; Fri, 14 May 2021 16:17:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 21A9161353 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=deltatee.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id AD5CA6B006E; Fri, 14 May 2021 12:17:58 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A86696B0070; Fri, 14 May 2021 12:17:58 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9014E6B0071; Fri, 14 May 2021 12:17:58 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0195.hostedemail.com [216.40.44.195]) by kanga.kvack.org (Postfix) with ESMTP id 5A9856B006E for ; Fri, 14 May 2021 12:17:58 -0400 (EDT) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id ECA5EBBE7 for ; Fri, 14 May 2021 16:17:57 +0000 (UTC) X-FDA: 78140342994.23.D9552BE Received: from ale.deltatee.com (ale.deltatee.com [204.191.154.188]) by imf14.hostedemail.com (Postfix) with ESMTP id E99D4C0007C4 for ; Fri, 14 May 2021 16:17:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=deltatee.com; s=20200525; h=Subject:In-Reply-To:MIME-Version:Date: Message-ID:From:References:Cc:To:content-disposition; bh=UIw7EfWmD3A5GJzYN/3QOUOCIyHuFu16FWOPf7ANc9Y=; b=ifFUHGd+/63UwWC7Lc9/oor7EB 2xjO0Kj1AlFEpeDAwbOKeW8D81UORdDKkPxs7CF9lZHYha50YtQkAW8SwcBLPjO/SrcXyl30YTRho MbfBoG89yDCZm/Gp8aa++DAJcvdvSRYMC7EbFLh8FinG05Ku9EKpgWTM/v4BVl4jTXyWC3/LqjVgu bdtOV6sJX1hy0+oEpb6EvH7KJiIfkE8Gl1VaVjCNeplN1uBeqW+034RUscz+xQLCn+ISPdE0nf+rC ggxbKXYoIRATTWu1GzOpzi2ZHRBR0QVMYKgJfXEoeRUmTpW6t1lgOr2s3tTG29i7Rquf1zkW1OwXB T6ym8TIw==; Received: from guinness.priv.deltatee.com ([172.16.1.162]) by ale.deltatee.com with esmtp (Exim 4.92) (envelope-from ) id 1lhaVY-000693-Pi; Fri, 14 May 2021 10:17:49 -0600 To: Christoph Hellwig 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 , Dan Williams , Jason Gunthorpe , =?UTF-8?Q?Christian_K=c3=b6nig?= , John Hubbard , Don Dutile , Matthew Wilcox , Daniel Vetter , Jakowski Andrzej , Minturn Dave B , Jason Ekstrand , Dave Hansen , Xiong Jianxin , Bjorn Helgaas , Ira Weiny , Robin Murphy References: <20210513223203.5542-1-logang@deltatee.com> <20210513223203.5542-16-logang@deltatee.com> <20210514135712.GD4715@lst.de> From: Logan Gunthorpe Message-ID: <6615c351-9c28-3a74-8c43-4aeb7993fb98@deltatee.com> Date: Fri, 14 May 2021 10:17:48 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 In-Reply-To: <20210514135712.GD4715@lst.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-CA Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 172.16.1.162 X-SA-Exim-Rcpt-To: robin.murphy@arm.com, ira.weiny@intel.com, helgaas@kernel.org, jianxin.xiong@intel.com, dave.hansen@linux.intel.com, jason@jlekstrand.net, dave.b.minturn@intel.com, andrzej.jakowski@intel.com, daniel.vetter@ffwll.ch, willy@infradead.org, ddutile@redhat.com, jhubbard@nvidia.com, christian.koenig@amd.com, jgg@ziepe.ca, dan.j.williams@intel.com, sbates@raithlin.com, iommu@lists.linux-foundation.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, hch@lst.de X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH v2 15/22] dma-direct: Support PCI P2PDMA pages in dma-direct map_sg X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=deltatee.com header.s=20200525 header.b=ifFUHGd+; dmarc=none; spf=pass (imf14.hostedemail.com: domain of logang@deltatee.com designates 204.191.154.188 as permitted sender) smtp.mailfrom=logang@deltatee.com X-Stat-Signature: 77hcqb8h9atf4ubph1qozfp9384xrfcx X-Rspamd-Queue-Id: E99D4C0007C4 X-Rspamd-Server: rspam02 X-HE-Tag: 1621009076-743368 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 2021-05-14 7:57 a.m., Christoph Hellwig wrote: >> + for_each_sg(sgl, sg, nents, i) { >> + if (sg_is_dma_pci_p2pdma(sg)) { >> + sg_dma_unmark_pci_p2pdma(sg); >> + } else { > > Double space here. We also don't really need the curly braces to start > with. > >> + struct pci_p2pdma_map_state p2pdma_state = {}; >> + enum pci_p2pdma_map_type map; >> struct scatterlist *sg; >> + int i, ret; >> >> for_each_sg(sgl, sg, nents, i) { >> + if (is_pci_p2pdma_page(sg_page(sg))) { >> + map = pci_p2pdma_map_segment(&p2pdma_state, dev, sg); >> + switch (map) { > > Why not just: > > switch (pci_p2pdma_map_segment(&p2pdma_state, dev, > sg)) { > > (even better with a shorter name for p2pdma_state so that it all fits on > a single line)? > >> + case PCI_P2PDMA_MAP_BUS_ADDR: >> + continue; >> + case PCI_P2PDMA_MAP_THRU_HOST_BRIDGE: >> + /* >> + * Mapping through host bridge should be >> + * mapped normally, thus we do nothing >> + * and continue below. >> + */ > > I have a bit of a hard time parsing this comment. > >> + if (sg->dma_address == DMA_MAPPING_ERROR) { >> + ret = -EINVAL; >> goto out_unmap; >> + } >> sg_dma_len(sg) = sg->length; >> } >> >> @@ -411,7 +443,7 @@ int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents, >> >> out_unmap: >> dma_direct_unmap_sg(dev, sgl, i, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC); >> - return -EINVAL; >> + return ret; > > Maybe just initialize ret to -EINVAL at declaration time to simplify this > a bit? > All fair points, will fix in v3. Logan