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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 0619CC433DB for ; Fri, 22 Jan 2021 18:30:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B82EE23AC0 for ; Fri, 22 Jan 2021 18:30:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728575AbhAVSab (ORCPT ); Fri, 22 Jan 2021 13:30:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46442 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728685AbhAVSZV (ORCPT ); Fri, 22 Jan 2021 13:25:21 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8179DC06121F; Fri, 22 Jan 2021 10:21:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=w+YCOFAQ20hSAyDFKoDJi9oUpd/wXrc+UjaBZ8KRY6g=; b=VhhNNcH9eCkwstIUsY27bNh8JX FRoQeLt8IKiLqPTlZLqUJzQ0ELIadh/Oyui5aSmXQjsl4U1xpz1wRGvAyBg/Tu7ZoUjsKvoztOz+I 7wBPWWalu55Dkb3B4gndMpF1rMzhVpPsLaBIza12DNKUD3DkY5Of+8ZQcgm1zlRXFr3g/sO9qgZNO Ly/u3TBi2nZuK2bsVPwkgBv6/JofWNuPvfg0PKhbqDawPH53ubXcC20oIYZ235QhjW58bzYtt+CY1 UG5SvIhtRMPiqDloIdkkAByF+QO1IMqs0mRMCMH4I8NBMIPvB/zNQ+LsZ8TF+vmHwIZ4sTOKZ//G6 lRQAHopg==; Received: from hch by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1l312t-0014XY-EY; Fri, 22 Jan 2021 18:20:37 +0000 Date: Fri, 22 Jan 2021 18:20:31 +0000 From: Christoph Hellwig To: Lauri Kasanen Cc: Keith Busch , Christoph Hellwig , linux-mips@vger.kernel.org, tsbogend@alpha.franken.de, axboe@kernel.dk, linux-block@vger.kernel.org Subject: Re: [PATCH v9] block: Add n64 cart driver Message-ID: <20210122182031.GA255271@infradead.org> References: <20210122110043.f36cd22df1233754753518c1@gmx.com> <20210122111727.GA161970@infradead.org> <20210122155801.a24c328b7aefdcffb7d68576@gmx.com> <20210122161804.GA225607@infradead.org> <20210122182349.c98d8599f7593afefa43c9dd@gmx.com> <20210122163913.GA227449@infradead.org> <20210122185619.980fa4f713b8f57528c3af9e@gmx.com> <20210122171120.GA1728441@dhcp-10-100-145-180.wdc.com> <20210122200117.b1b1cda46cefc840595d2b09@gmx.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210122200117.b1b1cda46cefc840595d2b09@gmx.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Fri, Jan 22, 2021 at 08:01:17PM +0200, Lauri Kasanen wrote: > On Fri, 22 Jan 2021 09:11:20 -0800 > Keith Busch wrote: > > Each bio_vec segment is physically contiguous. > > What's the official way to get that buffer's physical address? I > couldn't find any driver that does DMA to the bio buffer, to use as an > example. Maybe used wrong keywords. In Linux we never DMA to the physical address, but the DMA address. For a bio with just a single bvec (that is a single contigous segment) we have the dma_map_bvec helper that is only used by the nvme-pci driver for special optimizations in the case of a single contigous segment.