Re: [dpdk-dev] [PATCH v1] vhost: add vq status check in async enqueue poll

["Fu, Patrick" <patrick.fu@intel.com>]

V2 patch sent with revised title

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Monday, July 20, 2020 11:58 PM
> To: Fu, Patrick <patrick.fu@intel.com>; dev@dpdk.org; Xia, Chenbo
> <chenbo.xia@intel.com>
> Subject: Re: [PATCH v1] vhost: add vq status check in async enqueue poll
> 
> What about this commit title?
> vhost: fix missing virtqueue status check in async path
> 
> On 7/16/20 5:30 PM, patrick.fu@intel.com wrote:
> > From: Patrick Fu <patrick.fu@intel.com>
> >
> > Vring should not be touched if vq is disabled. This patch adds the vq
> > status check in async enqueue polling to avoid accessing to a disabled
> > queue.
> >
> > Fixes: cd6760da1076 ("vhost: introduce async enqueue for split ring")
> >
> > Signed-off-by: Patrick Fu <patrick.fu@intel.com>
> > ---
> >  lib/librte_vhost/virtio_net.c | 8 +++++---
> >  1 file changed, 5 insertions(+), 3 deletions(-)
> >
> > diff --git a/lib/librte_vhost/virtio_net.c
> > b/lib/librte_vhost/virtio_net.c index 1d0be3dd4..b197d76d3 100644
> > --- a/lib/librte_vhost/virtio_net.c
> > +++ b/lib/librte_vhost/virtio_net.c
> > @@ -1686,9 +1686,11 @@ uint16_t
> rte_vhost_poll_enqueue_completed(int
> > vid, uint16_t queue_id,
> >
> >  	if (n_pkts_put) {
> >  		vq->async_pkts_inflight_n -= n_pkts_put;
> > -		__atomic_add_fetch(&vq->used->idx, n_descs,
> __ATOMIC_RELEASE);
> > -
> > -		vhost_vring_call_split(dev, vq);
> > +		if (likely(vq->enabled && vq->access_ok)) {
> > +			__atomic_add_fetch(&vq->used->idx,
> > +					n_descs, __ATOMIC_RELEASE);
> > +			vhost_vring_call_split(dev, vq);
> > +		}
> >  	}
> >
> >  	if (start_idx + n_pkts_put <= vq_size) {
> >