From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <hch@lst.de>
Received: from verein.lst.de (verein.lst.de [213.95.11.211])
	by mail19.linbit.com (LINBIT Mail Daemon) with ESMTP id 2E751420949
	for <drbd-dev@lists.linbit.com>; Mon, 24 May 2021 09:29:54 +0200 (CEST)
Date: Mon, 24 May 2021 09:29:50 +0200
From: Christoph Hellwig <hch@lst.de>
To: Hannes Reinecke <hare@suse.de>
Message-ID: <20210524072950.GG23890@lst.de>
References: <20210521055116.1053587-1-hch@lst.de>
	<20210521055116.1053587-19-hch@lst.de>
	<1a771bf9-5083-c440-f0e1-5f6920b5b017@suse.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1a771bf9-5083-c440-f0e1-5f6920b5b017@suse.de>
Cc: nvdimm@lists.linux.dev, Ulf Hansson <ulf.hansson@linaro.org>,
	Mike Snitzer <snitzer@redhat.com>,
	linux-nvme@lists.infradead.org, Song Liu <song@kernel.org>,
	dm-devel@redhat.com, linux-bcache@vger.kernel.org,
	Christoph Hellwig <hch@lst.de>, drbd-dev@lists.linbit.com,
	linux-s390@vger.kernel.org, Dave Jiang <dave.jiang@intel.com>,
	Maxim Levitsky <maximlevitsky@gmail.com>,
	Vishal Verma <vishal.l.verma@intel.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Matias Bjorling <mb@lightnvm.io>, Nitin Gupta <ngupta@vflare.org>,
	Vasily Gorbik <gor@linux.ibm.com>, linux-xtensa@linux-xtensa.org,
	Alex Dubov <oakad@yahoo.com>, Heiko Carstens <hca@linux.ibm.com>,
	Coly Li <colyli@suse.de>, linux-block@vger.kernel.org,
	linux-m68k@lists.linux-m68k.org, Philip Kelleher <pjk1939@linux.ibm.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Jens Axboe <axboe@kernel.dk>, Chris Zankel <chris@zankel.net>,
	linux-raid@vger.kernel.org, Max Filippov <jcmvbkbc@gmail.com>,
	linux-mmc@vger.kernel.org, Philipp Reisner <philipp.reisner@linbit.com>,
	Jim Paris <jim@jtan.com>, Minchan Kim <minchan@kernel.org>,
	Lars Ellenberg <lars.ellenberg@linbit.com>, linuxppc-dev@lists.ozlabs.org
Subject: Re: [Drbd-dev] [PATCH 18/26] nvme-multipath: convert to
 blk_alloc_disk/blk_cleanup_disk
List-Id: "*Coordination* of development, patches,
	contributions -- *Questions* \(even to developers\) go to drbd-user,
	please." <drbd-dev.lists.linbit.com>
List-Unsubscribe: <https://lists.linbit.com/mailman/options/drbd-dev>,
	<mailto:drbd-dev-request@lists.linbit.com?subject=unsubscribe>
List-Archive: <http://lists.linbit.com/pipermail/drbd-dev>
List-Post: <mailto:drbd-dev@lists.linbit.com>
List-Help: <mailto:drbd-dev-request@lists.linbit.com?subject=help>
List-Subscribe: <https://lists.linbit.com/mailman/listinfo/drbd-dev>,
	<mailto:drbd-dev-request@lists.linbit.com?subject=subscribe>

On Sun, May 23, 2021 at 10:20:27AM +0200, Hannes Reinecke wrote:
> What about the check for GENHD_FL_UP a bit further up in line 766?
> Can this still happen with the new allocation scheme, ie is there still a 
> difference in lifetime between ->disk and ->disk->queue?

Yes, nvme_free_ns_head can still be called before device_add_disk was
called for an allocated nshead gendisk during error handling of the
setup path.  There is still a difference in the lifetime in that they
are separately refcounted, but it does not matter to the driver.