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From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Cc: Tiwei Bie <tiwei.bie@intel.com>,
	maxime.coquelin@redhat.com, zhihong.wang@intel.com, dev@dpdk.org,
	stable@dpdk.org
Subject: Re: [dpdk-dev] [PATCH] vhost: fix notification for packed ring
Date: Thu, 11 Oct 2018 09:36:48 -0400	[thread overview]
Message-ID: <20181011093628-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <ec712175-3425-02ad-0131-ea9ce595b00b@redhat.com>

On Thu, Oct 11, 2018 at 09:34:06PM +0800, Jason Wang wrote:
> 
> 
> On 2018年10月11日 21:06, Tiwei Bie wrote:
> > The notification can't be disabled in packed ring when
> > application tries to disable notification, because the
> > device event flags field is overwritten by an unexpected
> > value. This patch fixes this issue.
> > 
> > Fixes: b1cce26af1dc ("vhost: add notification for packed ring")
> > Cc: stable@dpdk.org
> > 
> > Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
> > ---
> >   lib/librte_vhost/vhost.c | 7 +++++--
> >   1 file changed, 5 insertions(+), 2 deletions(-)
> > 
> > diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
> > index e62f4c594..c9270bdec 100644
> > --- a/lib/librte_vhost/vhost.c
> > +++ b/lib/librte_vhost/vhost.c
> > @@ -667,8 +667,10 @@ vhost_enable_notify_packed(struct virtio_net *dev,
> >   {
> >   	uint16_t flags;
> > -	if (!enable)
> > -		vq->device_event->flags = VRING_EVENT_F_DISABLE;
> > +	if (!enable) {
> > +		flags = VRING_EVENT_F_DISABLE;
> > +		goto out;
> > +	}
> >   	flags = VRING_EVENT_F_ENABLE;
> >   	if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
> > @@ -677,6 +679,7 @@ vhost_enable_notify_packed(struct virtio_net *dev,
> >   			vq->avail_wrap_counter << 15;
> >   	}
> > +out:
> >   	rte_smp_wmb();
> 
> It looks to me the barrier is even not needed for !enable.
> 
> Thanks

Good point, I agree.
Besides that

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>



> >   	vq->device_event->flags = flags;

  reply	other threads:[~2018-10-11 13:36 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-11 13:06 Tiwei Bie
2018-10-11 13:17 ` Maxime Coquelin
2018-10-11 13:34 ` Jason Wang
2018-10-11 13:36   ` Michael S. Tsirkin [this message]
2018-10-11 14:10     ` Tiwei Bie
2018-10-11 14:22 ` [dpdk-dev] [PATCH v2] " Tiwei Bie
2018-10-11 15:21   ` Maxime Coquelin
2018-10-11 23:47   ` Jason Wang
2018-10-16  8:36   ` Maxime Coquelin

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