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=-7.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,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 70930C433B4 for ; Fri, 14 May 2021 16:30:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4BC936145E for ; Fri, 14 May 2021 16:30:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232362AbhENQbs (ORCPT ); Fri, 14 May 2021 12:31:48 -0400 Received: from ale.deltatee.com ([204.191.154.188]:33070 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230009AbhENQbs (ORCPT ); Fri, 14 May 2021 12:31:48 -0400 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=xV6ltS4lNS3Jm/f8TEnktWg1U1xW+UrFzR8b6RAQyww=; b=s//zBlCpwgQ1lLSn3XKJEQOaWd rI8rRBGrF3aoC3g+QuDXDug4GzbnkaS6nBtWhDM3pUOjQYKZYx/6iqfRigkJyI290iga8e7o+co0E QbXpFJsOWAQw7fOVJWNVDxDk/PaOaE0YGfRnol4IiEjPWjENwy9CRw8DjR6tZ+WmbEC0OTj1tjMV/ /DRMXbA8j4LTuFwWSHMlTxZaa7XowzY/YiYS5R+3nywlL9wmmsoR+uFEzvV5+oIlKCVP0Tyx8aJlM CWWYGc4JPwElN6+U10s+whCtXjoZyIVemlp2K/nOQSPMyhE1NnQR98UkoaVAkuMTzmLnP7RlAicuB 8O/5DBLg==; Received: from guinness.priv.deltatee.com ([172.16.1.162]) by ale.deltatee.com with esmtp (Exim 4.92) (envelope-from ) id 1lhahm-0006Ih-Qz; Fri, 14 May 2021 10:30:27 -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> <20210514140007.GE4715@lst.de> From: Logan Gunthorpe Message-ID: <91ce86db-e2f9-85ac-12db-91df72ac4648@deltatee.com> Date: Fri, 14 May 2021 10:30:25 -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: <20210514140007.GE4715@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 00/22] Add new DMA mapping operation for P2PDMA 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) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 2021-05-14 8:00 a.m., Christoph Hellwig wrote: > On Thu, May 13, 2021 at 04:31:41PM -0600, Logan Gunthorpe wrote: >> 17 files changed, 570 insertions(+), 290 deletions(-) > > I'm a little worried about all this extra code for no new functionality > at all. Yes, this series is really just prep work for allowing new functionality. And a bunch of cleanup has been tacked onto it. It should make adding P2PDMA in userspace a lot easier and I expect other P2PDMA use cases will be better enabled by it. A lot of people don't like the pci_p2pdma_map_sg() special case and can't use it in their use case because it only accepts homogenous SGLs. This series gets rid of the special case and allows it to be used more generally. Logan