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Date: Mon, 14 Apr 2025 08:19:10 +0200
From: Christoph Hellwig <hch@lst.de>
To: Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>, linux-block@vger.kernel.org,
	Nilay Shroff <nilay@linux.ibm.com>,
	Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>,
	Thomas =?iso-8859-1?Q?Hellstr=F6m?= <thomas.hellstrom@linux.intel.com>,
	Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH 07/15] block: move blk_unregister_queue() &
 device_del() after freeze wait
Message-ID: <20250414061910.GA6673@lst.de>
References: <20250410133029.2487054-1-ming.lei@redhat.com> <20250410133029.2487054-8-ming.lei@redhat.com>
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On Thu, Apr 10, 2025 at 09:30:19PM +0800, Ming Lei wrote:
> Move blk_unregister_queue() & device_del() after freeze wait, and prepare
> for unifying elevator switch.
> 
> This way is just fine, since bdev has been unhashed at the beginning of
> del_gendisk(), both blk_unregister_queue() & device_del() are dealing
> with kobject & debugfs thing only.

While I believe this is the right thing to do, moving the freeze wait
caused issues in the past, so be careful.  Take a look at:

commit 4c66a326b5ab784cddd72de07ac5b6210e9e1b06
Author: Christoph Hellwig <hch@lst.de>
Date:   Mon Sep 19 16:40:49 2022 +0200

    Revert "block: freeze the queue earlier in del_gendisk"