From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <kbusch@kernel.org>
Cc: Sagi Grimberg <sagi@grimberg.me>,
Keith Busch <keith.busch@wdc.com>, Christoph Hellwig <hch@lst.de>,
linux-nvme@lists.infradead.org, Hannes Reinecke <hare@suse.de>
Subject: Re: [PATCH] nvme: retrigger ANA log update if group descriptor isn't found
Date: Wed, 9 Dec 2020 08:35:45 +0100 [thread overview]
Message-ID: <20201209073545.GB10205@lst.de> (raw)
In-Reply-To: <20201208191703.GE27155@redsun51.ssa.fujisawa.hgst.com>
On Wed, Dec 09, 2020 at 04:17:03AM +0900, Keith Busch wrote:
> On Tue, Dec 08, 2020 at 03:03:52PM +0100, Christoph Hellwig wrote:
> > On Mon, Dec 07, 2020 at 07:46:50AM -0800, Keith Busch wrote:
> > > > But as I just outlined it just papers over buggy controllers. I really
> > > > don't think we should just silently do that.
> > >
> > > Okay, that's fine with me too. I agree with you on what the correct
> > > event sequence should be, but I just thought this looks like a fairly
> > > harmless work-around.
> >
> > I see three major downsides:
>
> You only listed two. :)
Yeah.
>
> > (1) it papers over our host side bug where we do not process the
> > different AENs in the order that the controller generated them
>
> We only have one AEN outstanding at a time, though, so we can't process
> them in a different order than the controller sent them, right?
In a more theoretical than practical race the next AEN could have
completed befoe the workqueue that executes the previous one has run.
> > (2) the code is black magic as there is no indicator why this condition
> > would happen
>
> Would it help if Hannes adds a dev_warn() that this log refresh is
> occuring from a controller's inconsistent reporting?
I really want to settle the discussion first as Fred has an extremely
strange interpretation of the spec.
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next prev parent reply other threads:[~2020-12-09 7:35 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-05 15:29 [PATCH] nvme: retrigger ANA log update if group descriptor isn't found Hannes Reinecke
2020-12-07 15:31 ` Keith Busch
2020-12-07 15:34 ` Christoph Hellwig
2020-12-07 15:46 ` Keith Busch
2020-12-08 14:03 ` Christoph Hellwig
2020-12-08 19:17 ` Keith Busch
2020-12-09 7:35 ` Christoph Hellwig [this message]
2020-12-07 15:51 ` Hannes Reinecke
2021-01-14 3:13 ` Sagi Grimberg
2021-03-25 10:55 ` George, Martin
2021-03-25 21:54 ` Keith Busch
2021-03-25 22:20 ` Sagi Grimberg
2021-04-02 16:49 ` Christoph Hellwig
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