From: Cornelia Huck <cornelia.huck@de.ibm.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org
Subject: Re: [PATCH 06/16] virtio_blk: drop config_enable
Date: Mon, 6 Oct 2014 14:55:05 +0200 [thread overview]
Message-ID: <20141006145505.697bc5ca.cornelia.huck@de.ibm.com> (raw)
In-Reply-To: <20141006123110.GA26815@redhat.com>
On Mon, 6 Oct 2014 15:31:10 +0300
"Michael S. Tsirkin" <mst@redhat.com> wrote:
> On Mon, Oct 06, 2014 at 02:20:38PM +0200, Cornelia Huck wrote:
> > On Mon, 6 Oct 2014 15:09:53 +0300
> > "Michael S. Tsirkin" <mst@redhat.com> wrote:
> >
> > > On Mon, Oct 06, 2014 at 01:42:29PM +0200, Cornelia Huck wrote:
> > > > On Sun, 5 Oct 2014 19:07:07 +0300
> > > > "Michael S. Tsirkin" <mst@redhat.com> wrote:
> > > >
> > > > > Now that virtio core ensures config changes don't
> > > > > arrive during probing, drop config_enable flag
> > > > > in virtio blk.
> > > > > On removal, flush is now sufficient to guarantee that
> > > > > no change work is queued.
> > > > >
> > > > > This help simplify the driver, and will allow
> > > > > setting DRIVER_OK earlier without losing config
> > > > > change notifications.
> > > > >
> > > > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > > > > ---
> > > > > drivers/block/virtio_blk.c | 19 ++-----------------
> > > > > 1 file changed, 2 insertions(+), 17 deletions(-)
> > > > >
> > > > > diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> > > > > index 0a58140..c8cf6a1 100644
> > > > > --- a/drivers/block/virtio_blk.c
> > > > > +++ b/drivers/block/virtio_blk.c
> > > >
> > > > > @@ -772,9 +766,7 @@ static void virtblk_remove(struct virtio_device *vdev)
> > > > > int refc;
> > > > >
> > > > > /* Prevent config work handler from accessing the device. */
> > > >
> > > > /* Common code ensures no further work will be queued. */
> > > >
> > > > instead?
> > >
> > > No, I think you missed the point:
> > > this comment now refers to the flush below: flush is required to
> > > ensure work handler is not running.
> > >
> > > Agree?
> >
> > I think we both mean the same thing.
> >
> > Preventing the handler from access sounds to me more like "when the
> > handler starts running, it is prevented from accessing the
> > device" (like with setting config_enable, as the code did before). What
> > I meant was "common code has already ensured that our work-queueing
> > function will not be called, therefore flushing the workqueue is
> > enough."
> >
> > (same for net)
>
> OK so I'll rewrite this to
> /* Make sure no work handler is accessing the device. */
> ?
> I prefer not duplicating core guarantees in all devices.
>
Sounds good to me.
next prev parent reply other threads:[~2014-10-06 12:55 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-05 16:06 [PATCH 00/16] virtio: fix spec compliance issues Michael S. Tsirkin
2014-10-05 16:06 ` [PATCH 01/16] virtio_pci: fix virtio spec compliance on restore Michael S. Tsirkin
2014-10-05 16:06 ` [PATCH 02/16] virtio: unify config_changed handling Michael S. Tsirkin
2014-10-06 9:20 ` Cornelia Huck
2014-10-05 16:06 ` [PATCH 03/16] virtio: refactor to use drv_to_virtio Michael S. Tsirkin
2014-10-06 10:34 ` Cornelia Huck
2014-10-05 16:07 ` [PATCH 04/16] virtio-pci: move freeze/restore to virtio core Michael S. Tsirkin
2014-10-06 10:54 ` Cornelia Huck
2014-10-05 16:07 ` [PATCH 05/16] virtio: defer config changed notifications Michael S. Tsirkin
2014-10-06 11:33 ` Cornelia Huck
2014-10-06 12:00 ` Michael S. Tsirkin
2014-10-05 16:07 ` [PATCH 06/16] virtio_blk: drop config_enable Michael S. Tsirkin
2014-10-06 11:42 ` Cornelia Huck
2014-10-06 12:09 ` Michael S. Tsirkin
2014-10-06 12:20 ` Cornelia Huck
2014-10-06 12:31 ` Michael S. Tsirkin
2014-10-06 12:55 ` Cornelia Huck [this message]
2014-10-05 16:07 ` [PATCH 07/16] virtio-blk: drop config_mutex Michael S. Tsirkin
2014-10-06 11:48 ` Cornelia Huck
2014-10-05 16:07 ` [PATCH 08/16] virtio_net: drop config_enable Michael S. Tsirkin
2014-10-06 11:50 ` Cornelia Huck
2014-10-06 12:10 ` Michael S. Tsirkin
2014-10-06 19:02 ` David Miller
2014-10-07 6:49 ` Michael S. Tsirkin
2014-10-07 15:36 ` David Miller
2014-10-07 15:42 ` Michael S. Tsirkin
2014-10-05 16:07 ` [PATCH 09/16] virtio-net: drop config_mutex Michael S. Tsirkin
2014-10-06 11:46 ` Sergei Shtylyov
2014-10-06 11:56 ` Michael S. Tsirkin
2014-10-06 12:07 ` Sergei Shtylyov
2014-10-06 12:22 ` Michael S. Tsirkin
2014-10-06 12:31 ` Sergei Shtylyov
2014-10-06 11:56 ` Cornelia Huck
2014-10-06 12:01 ` Michael S. Tsirkin
2014-10-05 16:07 ` [PATCH 10/16] virtio: add API to enable VQs early Michael S. Tsirkin
2014-10-06 14:08 ` Cornelia Huck
2014-10-06 14:51 ` Michael S. Tsirkin
2014-10-05 16:07 ` [PATCH 11/16] virtio_net: minor cleanup Michael S. Tsirkin
2014-10-06 12:06 ` Cornelia Huck
2014-10-05 16:07 ` [PATCH 12/16] virtio_net: enable VQs early Michael S. Tsirkin
2014-10-05 16:07 ` [PATCH 13/16] virtio_blk: " Michael S. Tsirkin
2014-10-05 16:07 ` [PATCH 14/16] virtio_console: " Michael S. Tsirkin
2014-10-05 16:07 ` [PATCH 15/16] 9p/trans_virtio: " Michael S. Tsirkin
2014-10-05 16:07 ` [PATCH 16/16] virtio_net: fix use after free on allocation failure Michael S. Tsirkin
2014-10-06 14:17 ` Cornelia Huck
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