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=-2.2 required=3.0 tests=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 79C55C76190 for ; Thu, 25 Jul 2019 20:28:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 513F5218EA for ; Thu, 25 Jul 2019 20:28:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726557AbfGYU2l (ORCPT ); Thu, 25 Jul 2019 16:28:41 -0400 Received: from ale.deltatee.com ([207.54.116.67]:43716 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725819AbfGYU2l (ORCPT ); Thu, 25 Jul 2019 16:28:41 -0400 Received: from s01061831bf6ec98c.cg.shawcable.net ([68.147.80.180] helo=[192.168.6.132]) by ale.deltatee.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.89) (envelope-from ) id 1hqkLl-0005E4-Ra; Thu, 25 Jul 2019 14:28:30 -0600 To: Keith Busch 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 References: <20190725172335.6825-1-logang@deltatee.com> <20190725172335.6825-5-logang@deltatee.com> <20190725175023.GA30641@bombadil.infradead.org> <20190725195835.GA7317@localhost.localdomain> From: Logan Gunthorpe Message-ID: <5dd6a41d-21c4-cf8d-a81d-271549de6763@deltatee.com> Date: Thu, 25 Jul 2019 14:28:28 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190725195835.GA7317@localhost.localdomain> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 68.147.80.180 X-SA-Exim-Rcpt-To: sbates@raithlin.com, maxg@mellanox.com, Chaitanya.Kulkarni@wdc.com, axboe@fb.com, sagi@grimberg.me, hch@lst.de, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, willy@infradead.org, kbusch@kernel.org X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH v6 04/16] nvme-core: introduce nvme_get_by_path() X-SA-Exim-Version: 4.2.1 (built Tue, 02 Aug 2016 21:08:31 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org 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. Logan