Date: Mon, 5 Jun 2017 10:18:17 +0200
From: Christoph Hellwig <hch@lst.de>
To: Sagi Grimberg <sagi@grimberg.me>
Cc: Christoph Hellwig <hch@lst.de>, Rakesh Pandit <rakesh@tuxera.com>,
        linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
        Jens Axboe <axboe@fb.com>, Keith Busch <keith.busch@intel.com>,
        Andy Lutomirski <luto@kernel.org>
Subject: Re: [PATCH V2] nvme: fix nvme_remove going to uninterruptible
        sleep for ever
Message-ID: <20170605081817.GA22122@lst.de>
References: <20170530071610.GA2679@hercules.tuxera.com> <4da7c939-1f54-80e5-48fc-06e58e14f018@grimberg.me> <20170530142346.GA39428@dhcp-216.srv.tuxera.com> <20170601114338.GA24855@lst.de> <bb2780a8-63af-4d58-6c78-b03152de0439@grimberg.me>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <bb2780a8-63af-4d58-6c78-b03152de0439@grimberg.me>
User-Agent: Mutt/1.5.17 (2007-11-01)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 939
Lines: 21

On Sun, Jun 04, 2017 at 06:28:15PM +0300, Sagi Grimberg wrote:
>
>> I think we need the NVME_CTRL_SCHED_RESET state.  In fact I'm pretty
>> sure some time in the past I already had it in a local tree as a
>> generalization of rdma and loop already use NVME_CTRL_RESETTING
>> (they set it before queueing the reset work).
>
> I don't remember having it, but I might be wrong...
>
> Can you explain again why you think we need it? Sorry for being
> difficult, but I'm not exactly sure why it makes things better
> or simpler.

Motly that we can treat a controller as under reset before scheduling
the reset work, both to prevent multiple schedules, and to make
checks like the one in nvme_should_reset robus.

But I think something along the lines of the earlier patch from
Rakesh that just sets the RESETTING state earlier + the cancel_work_sync
suggested by you should also work for that purpose.  So maybe that's
the way to go after all.