virtio-net: set queues after driver_ok

[ Upstream commit 51b813176f098ff61bd2833f627f5319ead098a5 ]

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: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index b7a4df4..55c20cc 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -3942,8 +3942,6 @@ static int virtnet_probe(struct virtio_device *vdev)
        if (vi->has_rss || vi->has_rss_hash_report)
                virtnet_init_default_rss(vi);
 
-       _virtnet_set_queues(vi, vi->curr_queue_pairs);
-
        /* serialize netdev register + virtio_device_ready() with ndo_open() */
        rtnl_lock();
 
@@ -3956,6 +3954,8 @@ static int virtnet_probe(struct virtio_device *vdev)
 
        virtio_device_ready(vdev);
 
+       _virtnet_set_queues(vi, vi->curr_queue_pairs);
+
        /* a random MAC address has been assigned, notify the device.
         * We don't fail probe if VIRTIO_NET_F_CTRL_MAC_ADDR is not there
         * because many devices work fine without getting MAC explicitly