From 167c25e4c5501f8b7e37f949d23652975c5a769c Mon Sep 17 00:00:00 2001
From: Jason Wang <jasowang@redhat.com>
Date: Wed, 10 Nov 2010 14:45:41 +0000
Subject: [PATCH] virtio-net: init link state correctly

For device that supports VIRTIO_NET_F_STATUS, there's no need to
assume the link is up and we need to call nerif_carrier_off() before
querying device status, otherwise we may get wrong operstate after
diver was loaded because the link watch event was not fired as
expected.

For device that does not support VIRITO_NET_F_STATUS, we could not get
its status through virtnet_update_status() and what we can only do is
always assuming the link is up.

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 drivers/net/virtio_net.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index bb6b67f6b0cc73..b6d402806ae672 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -986,9 +986,15 @@ static int virtnet_probe(struct virtio_device *vdev)
 		goto unregister;
 	}
 
-	vi->status = VIRTIO_NET_S_LINK_UP;
-	virtnet_update_status(vi);
-	netif_carrier_on(dev);
+	/* Assume link up if device can't report link status,
+	   otherwise get link status from config. */
+	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
+		netif_carrier_off(dev);
+		virtnet_update_status(vi);
+	} else {
+		vi->status = VIRTIO_NET_S_LINK_UP;
+		netif_carrier_on(dev);
+	}
 
 	pr_debug("virtnet: registered device %s\n", dev->name);
 	return 0;
-- 
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