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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, 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 E7356C433E0 for ; Tue, 16 Jun 2020 12:24:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C079620C56 for ; Tue, 16 Jun 2020 12:24:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=javigon-com.20150623.gappssmtp.com header.i=@javigon-com.20150623.gappssmtp.com header.b="NdH81GWD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728959AbgFPMYx (ORCPT ); Tue, 16 Jun 2020 08:24:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43158 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725901AbgFPMYv (ORCPT ); Tue, 16 Jun 2020 08:24:51 -0400 Received: from mail-wr1-x441.google.com (mail-wr1-x441.google.com [IPv6:2a00:1450:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E4FC9C08C5C2 for ; Tue, 16 Jun 2020 05:24:50 -0700 (PDT) Received: by mail-wr1-x441.google.com with SMTP id q11so20575773wrp.3 for ; Tue, 16 Jun 2020 05:24:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=javigon-com.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to; bh=/kIpCjCnT58JEG0mlUt9/EOieRJkzoytsmJ6uVIikG4=; b=NdH81GWDoVE8IpZvXIvmiD9pU0wl/DubsUnumfs2pm8ffF3/3S9hBD32MTJQ12z3vx tg+dvD1OBOPIIMfoFOGk8RV18xUtaOOG8r1frHLCXDyZa2037wz5VWo8pQsNjxVoNafo HnjBoCefxCRABCpMcrPb0BSu1NUoZjHiH6BkJSxsO9mwIyUSe9N9FN4un3UmTdZ5Kfxd PjRvVXJvHjaLpZbx8B4mm1LmS7fRs9wJUtrZ2r0ZyQrUpMXKBK46cGAva0TGw9KZHjz6 E2R2EFQZX7SgzqxBYkoZ094rpMpCmzMAvvUkkXFn1YBvtJRUKQ1V6mjUvr6vRRZ8aECI ZsBA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=/kIpCjCnT58JEG0mlUt9/EOieRJkzoytsmJ6uVIikG4=; b=Cr26h8jpJF4j+tSyljH4o0yMT6yuKKY98RIumzM9qwg3NpkVU+FpuBewytXTLcRAvh chc9t8Ho0UuG/vt6YfPZ9W/0/l2oH+tQO2Jh00Uj140ReJc4+olrTH29sdZeHNMF6Ps3 wb0ULORLe345vVFkN+2lr3UItKeOT2v3LHUSGOFc4wcvqhO3xlbXwEYEaqyqzbQJg64s xjJ1yvmVi6Fysf/T4dgV4Gipz+SReoJZFPPP0w9dX6wqLtUbR5tKaDUKtoN0EEvQAtsX edHfcTBMcoazSPl/4z1usRk9073JEMqufFvs/WDxAz9W6aLprVkJOIuKUCt+QOpfldeS zwsQ== X-Gm-Message-State: AOAM531CE+rP/ikNARHljrzR3p16Ixvt8xSxA3UhDTdmouSpA8bLcm4l B/uviCi+VKH0xQE13Yqt1GRqZQ== X-Google-Smtp-Source: ABdhPJxdYMJPpziDe8iXirHeV1pcVKa8DYd2hmGQF7C8+5WnJxa7+yKYZEo/WSDPHXONxAKse1WU/g== X-Received: by 2002:a5d:56c3:: with SMTP id m3mr2807086wrw.393.1592310289602; Tue, 16 Jun 2020 05:24:49 -0700 (PDT) Received: from localhost ([194.62.217.57]) by smtp.gmail.com with ESMTPSA id w10sm29085408wrp.16.2020.06.16.05.24.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 16 Jun 2020 05:24:48 -0700 (PDT) Date: Tue, 16 Jun 2020 14:24:48 +0200 From: Javier =?utf-8?B?R29uesOhbGV6?= To: Matias =?utf-8?B?QmrDuHJsaW5n?= Cc: Keith Busch , linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, Damien Le Moal , Matias =?utf-8?B?QmrDuHJsaW5n?= , Christoph Hellwig , Sagi Grimberg , Jens Axboe , Hans Holmberg , Dmitry Fomichev , Ajay Joshi , Aravind Ramesh , Niklas Cassel Subject: Re: [PATCH 5/5] nvme: support for zoned namespaces Message-ID: <20200616122448.4e3slfghv4cojafq@mpHalley.local> References: <20200615233424.13458-1-keith.busch@wdc.com> <20200615233424.13458-6-keith.busch@wdc.com> <20200616104142.zxw25txhsg2eyhsb@mpHalley.local> <20200616120018.en337lcs5y2jh5ne@mpHalley.local> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 16.06.2020 14:06, Matias Bjørling wrote: >On 16/06/2020 14.00, Javier González wrote: >>On 16.06.2020 13:18, Matias Bjørling wrote: >>>On 16/06/2020 12.41, Javier González wrote: >>>>On 16.06.2020 08:34, Keith Busch wrote: >>>>>Add support for NVM Express Zoned Namespaces (ZNS) Command Set defined >>>>>in NVM Express TP4053. Zoned namespaces are discovered based on their >>>>>Command Set Identifier reported in the namespaces Namespace >>>>>Identification Descriptor list. A successfully discovered Zoned >>>>>Namespace will be registered with the block layer as a host managed >>>>>zoned block device with Zone Append command support. A namespace that >>>>>does not support append is not supported by the driver. >>>> >>>>Why are we enforcing the append command? Append is optional on the >>>>current ZNS specification, so we should not make this mandatory in the >>>>implementation. See specifics below. >> >>> >>>There is already general support in the kernel for the zone append >>>command. Feel free to submit patches to emulate the support. It is >>>outside the scope of this patchset. >>> >> >>It is fine that the kernel supports append, but the ZNS specification >>does not impose the implementation for append, so the driver should not >>do that either. >> >>ZNS SSDs that choose to leave append as a non-implemented optional >>command should not rely on emulated SW support, specially when >>traditional writes work very fine for a large part of current ZNS use >>cases. >> >>Please, remove this virtual constraint. > >The Zone Append command is mandatory for zoned block devices. Please >see https://lwn.net/Articles/818709/ for the background. I do not see anywhere in the block layer that append is mandatory for zoned devices. Append is emulated on ZBC, but beyond that there is no mandatory bits. Please explain. > Please submitpatches if you want to have support for ZNS devices that > does not implement the Zone Append command. It is outside the scope > of this patchset. That we will.