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=-5.2 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 6EF47C83016 for ; Tue, 1 Dec 2020 19:39:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 35DAF206E3 for ; Tue, 1 Dec 2020 19:39:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392441AbgLATjH (ORCPT ); Tue, 1 Dec 2020 14:39:07 -0500 Received: from verein.lst.de ([213.95.11.211]:51136 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727534AbgLATjF (ORCPT ); Tue, 1 Dec 2020 14:39:05 -0500 Received: by verein.lst.de (Postfix, from userid 2407) id 7A23967373; Tue, 1 Dec 2020 20:38:23 +0100 (CET) Date: Tue, 1 Dec 2020 20:38:23 +0100 From: Christoph Hellwig To: Keith Busch Cc: Javier =?iso-8859-1?Q?Gonz=E1lez?= , Minwoo Im , linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, hch@lst.de, sagi@grimberg.me Subject: Re: [PATCH 4/4] nvme: enable char device per namespace Message-ID: <20201201193823.GA3522@lst.de> References: <20201201125610.17138-1-javier.gonz@samsung.com> <20201201125610.17138-5-javier.gonz@samsung.com> <20201201140348.GA5138@localhost.localdomain> <20201201185732.unlurqed2kaqwjsb@MacBook-Pro.localdomain> <20201201193002.GB27728@redsun51.ssa.fujisawa.hgst.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201201193002.GB27728@redsun51.ssa.fujisawa.hgst.com> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Wed, Dec 02, 2020 at 04:30:02AM +0900, Keith Busch wrote: > > > In multi-path, private namespaces for a head are not in /dev, so I don't > > > think this will hurt private namespaces (e.g., nvme0c0n1), But it looks > > > like it will make a little bit confusions between chardev and hidden blkdev. > > > > > > I don't against to update nvme-cli things also even naming conventions are > > > going to become different than nvmeXcYnZ. > > > > Agree. But as I understand it, Keith had a good argument to keep names > > aligned with the hidden bdev. > > My suggested naming makes it as obvious as possible that the character > device in /dev/ and the hidden block device in /sys/ are referring to > the same thing. What is confusing about that? > > > It is also true that in that comment he suggested nesting the char > > device in /dev/nvme > > Yeah, I'm okay with sub-directories for these special handles, but there > are arguments against it too. I don't feel that strongly about it either > way. I'd prefer different naming for the char vs the block devices. Yes, this will require a little work in the userspace tools to support the character device, but I think it is much cleaner. Devices in subdirectories of /dev/ are very rare and keep causing problem with userspace tooling for the few drivers that use them, so I don't think they are a good idea. 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=-6.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 0145BC64E7B for ; Tue, 1 Dec 2020 19:38:34 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4DDA5206E3 for ; Tue, 1 Dec 2020 19:38:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="nWhWva0x" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4DDA5206E3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=GY+wYJ9Hni3zvtJ63UlrSDMyQhRYmIP6sCLm6XkeQ5I=; b=nWhWva0xpkoxj+g5Ydi101cez EiIK25JRt7EFdiRcrUbRu9RFjfui1SePGWNigVDIhz8fYbsrE/kQUjAVDaF0Pko5TH0s6ubcyhQEi 3/MAB/jojuLng0djahWspj+fkvL/CKake3pD+u1t/hJ5jDVVLfZDnquk+GPjTbyqtYuAY25AXi79/ /dZCsWC15y3Btbes91BKmKmuSxgDhLtCDYY4OXa6tvzwljtkS/KjPS5A0DGlLEc/R3KnT/zMX9LEx rmoz5WcKyym1UA/JravR1HAw+Rh9OHKiRnvBJUXj9ZT577VxbNZCfazV9/Ao+XMbl+fJNbLPo5LuU A7sdZznAg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kkBTp-0006kZ-C4; Tue, 01 Dec 2020 19:38:29 +0000 Received: from verein.lst.de ([213.95.11.211]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kkBTl-0006iR-P7 for linux-nvme@lists.infradead.org; Tue, 01 Dec 2020 19:38:26 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 7A23967373; Tue, 1 Dec 2020 20:38:23 +0100 (CET) Date: Tue, 1 Dec 2020 20:38:23 +0100 From: Christoph Hellwig To: Keith Busch Subject: Re: [PATCH 4/4] nvme: enable char device per namespace Message-ID: <20201201193823.GA3522@lst.de> References: <20201201125610.17138-1-javier.gonz@samsung.com> <20201201125610.17138-5-javier.gonz@samsung.com> <20201201140348.GA5138@localhost.localdomain> <20201201185732.unlurqed2kaqwjsb@MacBook-Pro.localdomain> <20201201193002.GB27728@redsun51.ssa.fujisawa.hgst.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201201193002.GB27728@redsun51.ssa.fujisawa.hgst.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201201_143825_974496_7FB04C15 X-CRM114-Status: GOOD ( 19.88 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Javier =?iso-8859-1?Q?Gonz=E1lez?= , sagi@grimberg.me, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, Minwoo Im , hch@lst.de Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Wed, Dec 02, 2020 at 04:30:02AM +0900, Keith Busch wrote: > > > In multi-path, private namespaces for a head are not in /dev, so I don't > > > think this will hurt private namespaces (e.g., nvme0c0n1), But it looks > > > like it will make a little bit confusions between chardev and hidden blkdev. > > > > > > I don't against to update nvme-cli things also even naming conventions are > > > going to become different than nvmeXcYnZ. > > > > Agree. But as I understand it, Keith had a good argument to keep names > > aligned with the hidden bdev. > > My suggested naming makes it as obvious as possible that the character > device in /dev/ and the hidden block device in /sys/ are referring to > the same thing. What is confusing about that? > > > It is also true that in that comment he suggested nesting the char > > device in /dev/nvme > > Yeah, I'm okay with sub-directories for these special handles, but there > are arguments against it too. I don't feel that strongly about it either > way. I'd prefer different naming for the char vs the block devices. Yes, this will require a little work in the userspace tools to support the character device, but I think it is much cleaner. Devices in subdirectories of /dev/ are very rare and keep causing problem with userspace tooling for the few drivers that use them, so I don't think they are a good idea. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme