On Fri, Sep 23, 2016 at 06:04:06PM +0800, Chen Hanxiao wrote: > From: Chen Hanxiao <[email protected]> > > If backend(such as dpdk) lack the feather,
Sorry, I don't understand what does this mean. > don't assume it in vring_enable. > Or we may fail in vhost_net_start, then we can't use vhost. > This will bring compat issue with old version backend. > > Signed-off-by: Chen Hanxiao <[email protected]> > --- > v2: return 0 there if protocol features aren't negotiated. > > hw/net/vhost_net.c | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) > > diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c > index f2d49ad..a1b796a 100644 > --- a/hw/net/vhost_net.c > +++ b/hw/net/vhost_net.c > @@ -425,11 +425,17 @@ int vhost_set_vring_enable(NetClientState *nc, int > enable) > { > VHostNetState *net = get_vhost_net(nc); > const VhostOps *vhost_ops = net->dev.vhost_ops; > - > - nc->vring_enable = enable; > + int ret; > > if (vhost_ops && vhost_ops->vhost_set_vring_enable) { > - return vhost_ops->vhost_set_vring_enable(&net->dev, enable); > + ret = vhost_ops->vhost_set_vring_enable(&net->dev, enable); > + /* > + * Try to enable vring feature. What does this mean? > + * If protocol features aren't negotiated, return 0 for back compat. How do you mean "for back compat"? > + */ > + if (ret == 0) { > + nc->vring_enable = enable; > + } > } This clearly does not set vring_enable if vhost_set_vring_enable is NULL. > > return 0; > -- > 1.8.3.1 >
