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=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 1EC43C3A5A2 for ; Tue, 3 Sep 2019 16:48:04 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id E55462053B for ; Tue, 3 Sep 2019 16:48:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="E+diGmnT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E55462053B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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=bombadil.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=qEQMqHRZaj4B9j8rY4LP4APeC6XLnTvUU1yi19EeB1Y=; b=E+diGmnT1EWUbq LbWwi9qs+a7dcieOB3Cd328wFQJqpVoZ6mW6p/MSXlOudbDTy5L7XxU+X2MlZjDjF7/ynkIKGIqqz M4RDGPRkp8A9XzgEHRNaU9QU2h6sPOdxzBZlcHEtpHA9gm3Y/5M+lKPr1h00ilAdrh3mzD4HGDtC7 Vo7G5XghteQw9aogzkC2SLwCuHpjdqa8SQJMp5e8H26Fh6o2hSgAsyB4iMY+cHOwi6lQba74U1Yq8 ygzRwwsz4xm1vxURl0ONEB/1rPvEm5RMErtxrMrOjyWkeWwHbRPC6qS249/sqziSG4PPlbdCuLRCy JgNO5PM4fQSqScb23zrg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1i5ByI-00014V-IP; Tue, 03 Sep 2019 16:47:58 +0000 Received: from mga05.intel.com ([192.55.52.43]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1i5ByF-00011q-VU for linux-nvme@lists.infradead.org; Tue, 03 Sep 2019 16:47:57 +0000 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Sep 2019 09:47:54 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,463,1559545200"; d="scan'208";a="207151406" Received: from unknown (HELO localhost.localdomain) ([10.232.112.69]) by fmsmga004.fm.intel.com with ESMTP; 03 Sep 2019 09:47:53 -0700 Date: Tue, 3 Sep 2019 10:46:20 -0600 From: Keith Busch To: Logan Gunthorpe Subject: Re: [PATCH] nvme-core: Fix subsystem instance mismatches Message-ID: <20190903164620.GA20847@localhost.localdomain> References: <20190831000139.7662-1-logang@deltatee.com> <20190831152910.GA29439@localhost.localdomain> <33af4d94-9f6d-9baa-01fa-0f75ccee263e@deltatee.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <33af4d94-9f6d-9baa-01fa-0f75ccee263e@deltatee.com> User-Agent: Mutt/1.9.1 (2017-09-22) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190903_094756_030040_B64B90B4 X-CRM114-Status: GOOD ( 15.20 ) 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: Jens Axboe , Hannes Reinecke , Sagi Grimberg , "Martin K . Petersen" , linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, Keith Busch , Christoph Hellwig 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 Tue, Sep 03, 2019 at 10:08:01AM -0600, Logan Gunthorpe wrote: > On 2019-08-31 9:29 a.m., Keith Busch wrote: > > On Fri, Aug 30, 2019 at 06:01:39PM -0600, Logan Gunthorpe wrote: > >> To fix this, assign the subsystem's instance based on the instance > >> number of the controller's instance that first created it. There should > >> always be fewer subsystems than controllers so the should not be a need > >> to create extra subsystems that overlap existing controllers. > > > > The subsystem's lifetime is not tied to the controller's. When the > > controller is removed and releases its instance, the next controller > > to take that available instance will create naming collisions with the > > subsystem still using it. > > > > Hmm, yes, ok. > > So perhaps we can just make the subsystem prefer the ctrl's instance > when allocating the ID? Then at least, in the common case, the > controller numbers will match the subsystem numbers. Only when there's > random hot-plugs would the numbers get out of sync. I really don't know about a patch that works only on static configurations. Connects and disconnects do happen on live systems, so the numerals will inevitably get out of sync. Could we possibly make /dev/nvmeX be a subsystem handle without causing trouble for anyone? This would essentially be the same thing as today for non-CMIC controllers with a device-per-controller and only affects the CMIC ones. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme