virtio-net: set queues after driver_ok

commit 51b813176f098ff61bd2833f627f5319ead098a5 upstream.

Commit 25266128fe16 ("virtio-net: fix race between set queues and
probe") tries to fix the race between set queues and probe by calling
_virtnet_set_queues() before DRIVER_OK is set. This violates virtio
spec. Fixing this by setting queues after virtio_device_ready().

Note that rtnl needs to be held for userspace requests to change the
number of queues. So we are serialized in this way.

Fixes: 25266128fe16 ("virtio-net: fix race between set queues and probe")
Reported-by: Dragos Tatulea <dtatulea@nvidia.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 165149bcf0b1a3a3cfd128980d039aaa5fe775c9..2fd5d2b7a209242d3225cc5714ff15119f19f6bf 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -3220,8 +3220,6 @@ static int virtnet_probe(struct virtio_device *vdev)
                }
        }
 
-       _virtnet_set_queues(vi, vi->curr_queue_pairs);
-
        /* serialize netdev register + virtio_device_ready() with ndo_open() */
        rtnl_lock();
 
@@ -3234,6 +3232,8 @@ static int virtnet_probe(struct virtio_device *vdev)
 
        virtio_device_ready(vdev);
 
+       _virtnet_set_queues(vi, vi->curr_queue_pairs);
+
        rtnl_unlock();
 
        err = virtnet_cpu_notif_add(vi);