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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5B51DC3064D for ; Tue, 25 Jun 2024 18:19:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=YzvkjLDvBzgff6/Y2UShPenzq+MiJByf5DuVF2Ma4LE=; b=e5SmjLATbk/K/5e0UW9KoXqlhT LN7RwgFmupmAgUOczw4xqb2dYFVO2oQcPlCcvZME8lgaL0wfha2mhYGieKDIMiLCGUEAM9Uvi3c75 r492edUZS1PB+7Yxna0WjYuLDpIpU+F6IwAbUyZfdKzd59eGXms4k2eWdEEfsavQri7ESZpaGhN1K HTDbiEIeMmSBFTJ1PVzzQw9WZjQHfPMNi5TT1cB0J31CGTdimEWR6XGCj53r1UZ/EhqT/w8kUc+yp Ctzc9SqOXZY9maYrQt88aZZwilUH5k/hAos45xEDUq9WodhS9IHcDeM9IuKavWvE/+dzlidbgLWVw sCqXzT0w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sMAlB-000000044AN-3fNF; Tue, 25 Jun 2024 18:19:17 +0000 Received: from 008.lax.mailroute.net ([199.89.1.11]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sMAl5-0000000446A-1dnD for linux-nvme@lists.infradead.org; Tue, 25 Jun 2024 18:19:16 +0000 Received: from localhost (localhost [127.0.0.1]) by 008.lax.mailroute.net (Postfix) with ESMTP id 4W7tQ572yWz6Cnk9F; Tue, 25 Jun 2024 18:19:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=acm.org; h= content-transfer-encoding:content-type:content-type:in-reply-to :from:from:content-language:references:subject:subject :user-agent:mime-version:date:date:message-id:received:received; s=mr01; t=1719339540; x=1721931541; bh=YzvkjLDvBzgff6/Y2UShPenz q+MiJByf5DuVF2Ma4LE=; b=VJtFrKlWbGSrbirv0j3fQqvdos967ZrYLzAxYJgm PXwvoE0aJJklxBf4QXD/c1iDHZop7cYBum5ylRh6MG+DHkP4noMMd9/wGUbD+CaP P2+4A4qB5jq3sTTummCbWw4jx3ZfypYZW6wJ1dhX8By6ha/HTnuyxALoaBdrEA0p 9ed49lLfeZoa+DoMO2kJ5kIQUmeXeNSlZRQHnxk8jlVDNC+ffqKC8TrzL2NaI4SZ c+dUsSsmj8xofSXGA4qMOMyPgcvxz2uLthFm6DDhMTUpUQfNPIXmz80QQ7tfsoTm hIVbH9sPkKVIAXWFts/Ks3kvlDKUEl1ZmyhH2XxKcZ0voQ== X-Virus-Scanned: by MailRoute Received: from 008.lax.mailroute.net ([127.0.0.1]) by localhost (008.lax [127.0.0.1]) (mroute_mailscanner, port 10029) with LMTP id AFhXlXXr1W3q; Tue, 25 Jun 2024 18:19:00 +0000 (UTC) Received: from [100.96.154.26] (unknown [104.132.0.90]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bvanassche@acm.org) by 008.lax.mailroute.net (Postfix) with ESMTPSA id 4W7tPs1TX4z6Cnk97; Tue, 25 Jun 2024 18:18:56 +0000 (UTC) Message-ID: Date: Tue, 25 Jun 2024 11:18:56 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v20 02/12] Add infrastructure for copy offload in block and request layer. To: Damien Le Moal , Nitesh Shetty , Christoph Hellwig Cc: Jens Axboe , Jonathan Corbet , Alasdair Kergon , Mike Snitzer , Mikulas Patocka , Keith Busch , Sagi Grimberg , Chaitanya Kulkarni , Alexander Viro , Christian Brauner , Jan Kara , martin.petersen@oracle.com, david@fromorbit.com, hare@suse.de, damien.lemoal@opensource.wdc.com, anuj20.g@samsung.com, joshi.k@samsung.com, nitheshshetty@gmail.com, gost.dev@samsung.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, dm-devel@lists.linux.dev, linux-nvme@lists.infradead.org, linux-fsdevel@vger.kernel.org References: <9f1ec1c1-e1b8-48ac-b7ff-8efb806a1bc8@kernel.org> <665850bd.050a0220.a5e6b.5b72SMTPIN_ADDED_BROKEN@mx.google.com> <20240601055931.GB5772@lst.de> <20240604044042.GA29094@lst.de> <4ffad358-a3e6-4a88-9a40-b7e5d05aa53c@acm.org> <20240605082028.GC18688@lst.de> <6679526f.170a0220.9ffd.aefaSMTPIN_ADDED_BROKEN@mx.google.com> <4ea90738-afd1-486c-a9a9-f7e2775298ff@acm.org> Content-Language: en-US From: Bart Van Assche In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240625_111911_889272_D8A9D629 X-CRM114-Status: GOOD ( 15.80 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On 6/24/24 2:55 PM, Damien Le Moal wrote: > I am still a little confused as to why we need 2 BIOs, one for src and one for > dst... Is it because of the overly complex scsi extended copy support ? > > Given that the main use case is copy offload for data within the same device, > using a single BIO which somehow can carry a list of LBA sources and a single > destination LBA would be far simpler and perfectly matching nvme simple copy and > ATA write gathered. And I think that this would also match the simplest case for > scsi extended copy as well. Hi Damien, What are the implications for the device mapper code if the copy source and destination LBAs are encoded in the bio payload instead of in bio->bi_sector? Thanks, Bart.