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From: Keith Busch <kbusch@kernel.org>
To: Sagi Grimberg <sagi@grimberg.me>
Cc: Edmund Nadolski <edmund.nadolski@intel.com>,
	Christoph Hellwig <hch@lst.de>,
	linux-nvme@lists.infradead.org,
	James Smart <james.smart@broadcom.com>
Subject: Re: [PATCHv2 6/6] nvme: Wait for reset state when required
Date: Fri, 20 Sep 2019 12:26:37 -0600	[thread overview]
Message-ID: <20190920182637.GD97854@C02WT3WMHTD6> (raw)
In-Reply-To: <debdee44-22a1-0361-9d20-4af6a11dab0d@grimberg.me>

On Fri, Sep 20, 2019 at 11:13:06AM -0700, Sagi Grimberg wrote:
> On 9/19/19 2:34 PM, kbusch@kernel.org wrote:
> >   static void nvme_reset_done(struct pci_dev *pdev)
> >   {
> >   	struct nvme_dev *dev = pci_get_drvdata(pdev);
> > -	nvme_reset_ctrl_sync(&dev->ctrl);
> > +
> > +	if (!nvme_reset_continue(&dev->ctrl))
> > +		flush_work(&dev->ctrl.reset_work);
> 
> Is nvme_reset_continue allowed to fail here?
> As I see it, the flush must complete regardless doesn't it?

I was thinking a surprise hot-removal, but no, the pci driver is holding
the device lock across the prepare/done sequence, so I don't think it's
possible for this reset_continue() to fail to schedule.
 
> >   }
> >   static void nvme_shutdown(struct pci_dev *pdev)
> >   {
> >   	struct nvme_dev *dev = pci_get_drvdata(pdev);
> > -	nvme_dev_disable(dev, true);
> > +	nvme_disable_prepare_reset(dev, true);
> >   }
> >   /*
> > @@ -2898,7 +2920,7 @@ static int nvme_resume(struct device *dev)
> >   	if (ndev->last_ps == U32_MAX ||
> >   	    nvme_set_power_state(ctrl, ndev->last_ps) != 0)
> > -		nvme_reset_ctrl(ctrl);
> > +		return nvme_reset_continue(&ndev->ctrl);
> 
> Is the controller allowed not to be in RESETTING in this stage?
> do we need a WARN_ON if it is?

This one, though, I think a hot removal can cause this to fail since the
device lock isn't held from suspend all the way through resume, so we
could be in the DELETING or DEAD state.

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  reply	other threads:[~2019-09-20 18:26 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-19 21:34 [PATCHv2 0/6] nvme: double reset prevention kbusch
2019-09-19 21:34 ` [PATCHv2 1/6] nvme-pci: Free tagset if no IO queues kbusch
2019-09-20 17:49   ` Sagi Grimberg
2019-09-20 17:53     ` Keith Busch
2019-09-20 17:56       ` Sagi Grimberg
2019-09-27 21:33   ` Christoph Hellwig
2019-09-19 21:34 ` [PATCHv2 2/6] nvme: Remove ADMIN_ONLY state kbusch
2019-09-20 17:53   ` Sagi Grimberg
2019-09-27 21:35   ` Christoph Hellwig
2019-09-19 21:34 ` [PATCHv2 3/6] nvme: Restart request timers in resetting state kbusch
2019-09-20 17:53   ` Sagi Grimberg
2019-09-27 21:36   ` Christoph Hellwig
2019-09-19 21:34 ` [PATCHv2 4/6] nvme: Introduce nvme_reset_continue kbusch
2019-09-20 18:15   ` Sagi Grimberg
2019-09-27 21:37   ` Christoph Hellwig
2019-09-27 21:44   ` Christoph Hellwig
2019-09-19 21:34 ` [PATCHv2 5/6] nvme: Prevent resets during paused states kbusch
2019-09-20 18:03   ` Sagi Grimberg
2019-09-20 18:05   ` Sagi Grimberg
2019-09-20 18:08     ` Keith Busch
2019-09-20 18:14       ` Sagi Grimberg
2019-09-27 21:41   ` Christoph Hellwig
2019-09-28  0:23     ` Keith Busch
     [not found]       ` <CGME20191010120317uscas1p1e4483ca19dbb0e550c413c18c5928537@uscas1p1.samsung.com>
2019-10-10 12:03         ` Judy Brock
2019-10-10 13:59           ` Keith Busch
2019-10-10 14:03             ` Christoph Hellwig
2019-10-11  0:51             ` Judy Brock
2019-10-11 14:23               ` Keith Busch
2019-09-19 21:34 ` [PATCHv2 6/6] nvme: Wait for reset state when required kbusch
2019-09-20 18:13   ` Sagi Grimberg
2019-09-20 18:26     ` Keith Busch [this message]
2019-09-20 19:29       ` Keith Busch
2019-09-20 20:49         ` Sagi Grimberg
2019-09-20 21:06           ` Keith Busch
2019-09-27 21:43   ` Christoph Hellwig
2019-09-20 17:51 ` [PATCHv2 0/6] nvme: double reset prevention Sagi Grimberg
2019-09-20 17:54   ` Keith Busch
2019-09-23 22:09 ` Sagi Grimberg
2019-09-24 15:07   ` Keith Busch
2019-09-24 18:07     ` Sagi Grimberg
2019-09-24 18:12       ` Keith Busch

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