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=-5.3 required=3.0 tests=BAYES_00, 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 C7BFBC56201 for ; Mon, 9 Nov 2020 09:13:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 529492080C for ; Mon, 9 Nov 2020 09:13:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 529492080C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 97B986B005D; Mon, 9 Nov 2020 04:13:02 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 9298A6B0068; Mon, 9 Nov 2020 04:13:02 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7F25A6B006C; Mon, 9 Nov 2020 04:13:02 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0025.hostedemail.com [216.40.44.25]) by kanga.kvack.org (Postfix) with ESMTP id 53BED6B005D for ; Mon, 9 Nov 2020 04:13:02 -0500 (EST) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id EA719180AD806 for ; Mon, 9 Nov 2020 09:13:01 +0000 (UTC) X-FDA: 77464315362.03.plot25_6202210272eb Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin03.hostedemail.com (Postfix) with ESMTP id BB71E28A4E9 for ; Mon, 9 Nov 2020 09:13:01 +0000 (UTC) X-HE-Tag: plot25_6202210272eb X-Filterd-Recvd-Size: 1653 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf06.hostedemail.com (Postfix) with ESMTP for ; Mon, 9 Nov 2020 09:13:01 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 8929268AFE; Mon, 9 Nov 2020 10:12:58 +0100 (CET) Date: Mon, 9 Nov 2020 10:12:58 +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 Subject: Re: [RFC PATCH 04/15] lib/scatterlist: Add flag for indicating P2PDMA segments in an SGL Message-ID: <20201109091258.GB28918@lst.de> References: <20201106170036.18713-1-logang@deltatee.com> <20201106170036.18713-5-logang@deltatee.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201106170036.18713-5-logang@deltatee.com> User-Agent: Mutt/1.5.17 (2007-11-01) 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 Fri, Nov 06, 2020 at 10:00:25AM -0700, Logan Gunthorpe wrote: > We make use of the top bit of the dma_length to indicate a P2PDMA > segment. I don't think "we" can. There is nothing limiting the size of a SGL segment.