vhost: avoid backend flush on vring ops
vring changes already do a flush internally where appropriate, so we do
not need a second flush.
It's currently not very expensive but a follow-up patch makes flush more
heavy-weight, so remove the extra flush here to avoid regressing
performance if call or kick fds are changed on data path.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index ff6c919..1802ab6 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -942,8 +942,11 @@
return vhost_net_reset_owner(n);
default:
mutex_lock(&n->dev.mutex);
- r = vhost_dev_ioctl(&n->dev, ioctl, arg);
- vhost_net_flush(n);
+ r = vhost_dev_ioctl(&n->dev, ioctl, argp);
+ if (r == -ENOIOCTLCMD)
+ r = vhost_vring_ioctl(&n->dev, ioctl, argp);
+ else
+ vhost_net_flush(n);
mutex_unlock(&n->dev.mutex);
return r;
}