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,DKIM_SIGNED, DKIM_VALID,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 18DCFC4361B for ; Sat, 12 Dec 2020 18:15:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E250F22581 for ; Sat, 12 Dec 2020 18:15:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2407677AbgLLSPn (ORCPT ); Sat, 12 Dec 2020 13:15:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33904 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727208AbgLLSPO (ORCPT ); Sat, 12 Dec 2020 13:15:14 -0500 Received: from mail-pj1-x1043.google.com (mail-pj1-x1043.google.com [IPv6:2607:f8b0:4864:20::1043]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2CA48C0613D6 for ; Sat, 12 Dec 2020 10:14:34 -0800 (PST) Received: by mail-pj1-x1043.google.com with SMTP id iq13so3980457pjb.3 for ; Sat, 12 Dec 2020 10:14:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=vPqkNEV8mHk/bP+lF6DmFa2iJcEPH5rRm6JP4KbBMo0=; b=uNnf2fVnys7JlLeW0LZFNtKvHbpjwOnfF1lAKwsomWXpUon3wNsJ4a3MFfW21IsGF3 wdYTHO4V0jE85+uNBbo9caN8aVHcCZHNhcBVIhhSYVdaIlUMv/yUuibNYaaM8qjjOzfH 07ESzSQ+tZiK2GPGzWyN7dtxk87LenjPiXmbeSkwoHtHwGfAwNekaG5L3PgsbLDhLnvk rHl91hu5kXyE+QCytGFWNyJJwBgG2wIDVa+Tr6DCvowP7S8xjBOsTcNFlGCrpsB+xu+r i6kqRktMbcC33kg+U9ohfDacpu7+ifKuNHeIrdACm6y3NAP+/89P3AfF+hbkSjZ4ohXX be3Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=vPqkNEV8mHk/bP+lF6DmFa2iJcEPH5rRm6JP4KbBMo0=; b=R7LjMZOIR9nDZ7OAS6YUV+X1yiz7DRq79GR/AtP9tXjTf/pXrXR7LpG5ESUczNK6+O ujBhdR1Q+vOszf0r3Oa85VgnjRLBu9B8vR5YtPXh+QP4O+QoiZZqeXqaufeQv46/Dmj4 PiH4qf8PNH8g6vyJjh/u0+W44La++pKu7kXcVsbJ7skjDnx/RAoo6LDQ5CyKNQVOSCQx SAvvYUfxSlxCbgBvmPK1MWDuDOC6nmomXb7r+z8yTeAiK7aU7mJy0cvYdbd2rh6lIN8s 8t8M1YEzmLwAoWdSP5VSJV9i3tecE5t0lpBc340uLxelymSJEm3cDUJj6wH4SalciYO+ 214Q== X-Gm-Message-State: AOAM530K/JXycfcKAI8S2yFaoa/RY5jPvkvInkjrukyrU5YtPbG/Tl96 nwdCslWVTI4X8lVCYHi8ZgyOy3brk1zQMQ== X-Google-Smtp-Source: ABdhPJyzLfzuB0KUyKGFSNr6IYFEPAE0OXxmdsTO8gURDuRU0fhyabebg0ctlKQwB8lLEJ+t16aEuA== X-Received: by 2002:a17:90a:df12:: with SMTP id gp18mr18051977pjb.43.1607796873727; Sat, 12 Dec 2020 10:14:33 -0800 (PST) Received: from [192.168.1.134] ([66.219.217.173]) by smtp.gmail.com with ESMTPSA id u24sm574816pjx.56.2020.12.12.10.14.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 12 Dec 2020 10:14:33 -0800 (PST) Subject: Re: [PATCH 0/3] block: blk_interposer - Block Layer Interposer To: Hannes Reinecke , Mike Snitzer , Sergei Shtepa , hch@lst.de Cc: "johannes.thumshirn@wdc.com" , "koct9i@gmail.com" , "ming.lei@redhat.com" , "josef@toxicpanda.com" , "steve@sk2.org" , "linux-block@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Pavel Tide , dm-devel@redhat.com References: <1607518911-30692-1-git-send-email-sergei.shtepa@veeam.com> <20201209135148.GA32720@redhat.com> <20201210145814.GA31521@veeam.com> <20201210163222.GB10239@redhat.com> <20201211163049.GC16168@redhat.com> <1ee7652e-b77f-6fa4-634c-ff6639037321@kernel.dk> <208edf35-ecdc-2d73-4c48-0424943a78c0@suse.de> <06b4a10d-5ea5-27e1-af0d-83d5c714996f@kernel.dk> From: Jens Axboe Message-ID: <6bc5ff77-4977-a9bd-3fb8-ce35e1179b94@kernel.dk> Date: Sat, 12 Dec 2020 11:14:31 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/11/20 11:03 AM, Hannes Reinecke wrote: > On 12/11/20 6:04 PM, Jens Axboe wrote: >> On 12/11/20 9:56 AM, Hannes Reinecke wrote: >>> On 12/11/20 5:33 PM, Jens Axboe wrote: >>>> On 12/11/20 9:30 AM, Mike Snitzer wrote: >>>>> While I still think there needs to be a proper _upstream_ consumer of >>>>> blk_interposer as a condition of it going in.. I'll let others make the >>>>> call. >>>> >>>> That's an unequivocal rule. >>>> >>>>> As such, I'll defer to Jens, Christoph and others on whether your >>>>> minimalist blk_interposer hook is acceptable in the near-term. >>>> >>>> I don't think so, we don't do short term bandaids just to plan on >>>> ripping that out when the real functionality is there. IMHO, the dm >>>> approach is the way to go - it provides exactly the functionality that >>>> is needed in an appropriate way, instead of hacking some "interposer" >>>> into the core block layer. >>>> >>> Which is my plan, too. >>> >>> I'll be working with the Veeam folks to present a joint patchset >>> (including the DM bits) for the next round. >> >> Just to be clear, core block additions for something that dm will >> consume is obviously fine. Adding this as block layer functionality than >> then exposes an application API for setting it up, tearing down, etc - >> that is definitely NOT >> > That was never my intention. > Any consumers of this thing would need to be in-kernel. > If that was your concern. Yep, that is/was indeed my concern! -- Jens Axboe