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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 9052EC76190 for ; Thu, 25 Jul 2019 20:34:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6AFA722C7D for ; Thu, 25 Jul 2019 20:34:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564086859; bh=Sslw0b3NB3GoI3NZZlFZ4IXYX/XVRSejkty5CZ58ar0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=Y99MfeG9pLVrIOtfD+ZbEZEQ3yF2PaVpEQ6rcZ6O9nVCpEs43FEFFZH+cbM6KRuxB oIIce04LJhkdhXbKBo7X+/RPviubvHpYD1d+yUuG7GMcq9H2wTK3UjfIqY4VTMExhF BsL/i4UXnEg2M/Dx3AAxYePQ6ujb/zWqcF9AXzh8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726791AbfGYUeO (ORCPT ); Thu, 25 Jul 2019 16:34:14 -0400 Received: from mga05.intel.com ([192.55.52.43]:29092 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726623AbfGYUeN (ORCPT ); Thu, 25 Jul 2019 16:34:13 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Jul 2019 13:34:10 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,308,1559545200"; d="scan'208";a="345618092" Received: from unknown (HELO localhost.localdomain) ([10.232.112.69]) by orsmga005.jf.intel.com with ESMTP; 25 Jul 2019 13:34:11 -0700 Date: Thu, 25 Jul 2019 14:31:18 -0600 From: Keith Busch To: Logan Gunthorpe Cc: Matthew Wilcox , linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, Christoph Hellwig , Sagi Grimberg , Jens Axboe , Chaitanya Kulkarni , Max Gurtovoy , Stephen Bates Subject: Re: [PATCH v6 04/16] nvme-core: introduce nvme_get_by_path() Message-ID: <20190725203118.GB7317@localhost.localdomain> References: <20190725172335.6825-1-logang@deltatee.com> <20190725172335.6825-5-logang@deltatee.com> <20190725175023.GA30641@bombadil.infradead.org> <20190725195835.GA7317@localhost.localdomain> <5dd6a41d-21c4-cf8d-a81d-271549de6763@deltatee.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5dd6a41d-21c4-cf8d-a81d-271549de6763@deltatee.com> User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Thu, Jul 25, 2019 at 02:28:28PM -0600, Logan Gunthorpe wrote: > > > On 2019-07-25 1:58 p.m., Keith Busch wrote: > > On Thu, Jul 25, 2019 at 11:54:18AM -0600, Logan Gunthorpe wrote: > >> > >> > >> On 2019-07-25 11:50 a.m., Matthew Wilcox wrote: > >>> On Thu, Jul 25, 2019 at 11:23:23AM -0600, Logan Gunthorpe wrote: > >>>> nvme_get_by_path() is analagous to blkdev_get_by_path() except it > >>>> gets a struct nvme_ctrl from the path to its char dev (/dev/nvme0). > >>>> > >>>> The purpose of this function is to support NVMe-OF target passthru. > >>> > >>> I can't find anywhere that you use this in this patchset. > >>> > >> > >> Oh sorry, the commit message is out of date the function was actually > >> called nvme_ctrl_get_by_path() and it's used in Patch 10. > > > > Instead of by path, could we have configfs take something else, like > > the unique controller instance or serial number? I know that's different > > than how we handle blocks and files, but that way nvme core can lookup > > the cooresponding controller without adding new cdev dependencies. > > Well the previous version of the patchset just used the ctrl name > ("nvme1") and looped through all the controllers to find a match. But > this sucks because of the inconsistency and the fact that the name can > change if hardware changes and the number changes. Allowing the user to > make use of standard udev rules seems important to me. Should we then create a new udev rule for persistent controller names? /dev/nvme1 may not be the same controller each time you refer to it.