From: "Durrant, Paul" <pdurrant@amazon.com>
To: "Jürgen Groß" <jgross@suse.com>,
"Roger Pau Monné" <roger.pau@citrix.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
"Stefano Stabellini" <sstabellini@kernel.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>
Subject: RE: [Xen-devel] [PATCH 2/4] xenbus: limit when state is forced to closed
Date: Mon, 9 Dec 2019 12:03:54 +0000 [thread overview]
Message-ID: <3412e42d13224b6786613e58dc189ebf@EX13D32EUC003.ant.amazon.com> (raw)
In-Reply-To: <b8a138ad-5770-65fa-f368-f7b4063702fa@suse.com>
> -----Original Message-----
> From: Jürgen Groß <jgross@suse.com>
> Sent: 09 December 2019 11:55
> To: Roger Pau Monné <roger.pau@citrix.com>; Durrant, Paul
> <pdurrant@amazon.com>
> Cc: linux-kernel@vger.kernel.org; xen-devel@lists.xenproject.org; Stefano
> Stabellini <sstabellini@kernel.org>; Boris Ostrovsky
> <boris.ostrovsky@oracle.com>
> Subject: Re: [Xen-devel] [PATCH 2/4] xenbus: limit when state is forced to
> closed
>
> On 09.12.19 12:39, Roger Pau Monné wrote:
> > On Thu, Dec 05, 2019 at 02:01:21PM +0000, Paul Durrant wrote:
> >> Only force state to closed in the case when the toolstack may need to
> >> clean up. This can be detected by checking whether the state in
> xenstore
> >> has been set to closing prior to device removal.
> >
> > I'm not sure I see the point of this, I would expect that a failure to
> > probe or the removal of the device would leave the xenbus state as
> > closed, which is consistent with the actual driver state.
> >
> > Can you explain what's the benefit of leaving a device without a
> > driver in such unknown state?
>
> And more concerning: did you check that no frontend/backend is
> relying on the closed state to be visible without closing having been
> set before?
Blkfront doesn't seem to mind and I believe the Windows PV drivers cope, but I don't really understand the comment since this patch is actually removing a case where the backend transitions directly to closed.
Paul
>
>
> Juergen
next prev parent reply other threads:[~2019-12-09 12:04 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-05 14:01 [PATCH 0/4] xen-blkback: support live update Paul Durrant
2019-12-05 14:01 ` [PATCH 1/4] xenbus: move xenbus_dev_shutdown() into frontend code Paul Durrant
2019-12-09 11:33 ` Jürgen Groß
2019-12-09 11:55 ` Durrant, Paul
2019-12-09 11:57 ` Jürgen Groß
2019-12-05 14:01 ` [PATCH 2/4] xenbus: limit when state is forced to closed Paul Durrant
2019-12-09 11:39 ` [Xen-devel] " Roger Pau Monné
2019-12-09 11:55 ` Jürgen Groß
2019-12-09 12:03 ` Durrant, Paul [this message]
2019-12-09 12:08 ` Jürgen Groß
2019-12-09 12:19 ` Durrant, Paul
2019-12-09 13:38 ` Jürgen Groß
2019-12-09 14:06 ` Durrant, Paul
2019-12-09 14:09 ` Jürgen Groß
2019-12-09 14:23 ` Durrant, Paul
2019-12-09 14:41 ` Jürgen Groß
2019-12-09 14:43 ` Durrant, Paul
2019-12-09 12:01 ` Durrant, Paul
2019-12-09 12:25 ` Roger Pau Monné
2019-12-09 12:40 ` Durrant, Paul
2019-12-09 14:28 ` Roger Pau Monné
2019-12-09 14:41 ` Durrant, Paul
2019-12-09 15:13 ` Roger Pau Monné
2019-12-09 16:26 ` Durrant, Paul
2019-12-09 17:17 ` Roger Pau Monné
2019-12-09 17:23 ` Durrant, Paul
2019-12-05 14:01 ` [PATCH 3/4] xen/interface: don't discard pending work in FRONT/BACK_RING_ATTACH Paul Durrant
2019-12-09 11:41 ` [Xen-devel] " Roger Pau Monné
2019-12-09 11:52 ` Jürgen Groß
2019-12-09 12:50 ` Durrant, Paul
2019-12-09 13:55 ` Jürgen Groß
2019-12-09 16:38 ` Durrant, Paul
2019-12-10 11:42 ` Jürgen Groß
2019-12-05 14:01 ` [PATCH 4/4] xen-blkback: support dynamic unbind/bind Paul Durrant
2019-12-09 12:17 ` Roger Pau Monné
2019-12-09 12:24 ` Durrant, Paul
2019-12-09 13:57 ` Jürgen Groß
2019-12-09 14:01 ` Durrant, Paul
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