IPoIB: Report operstate consistently when brought up without a link

After booting without a working link, "ip link" shows:

 5: mlx4_ib1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 2044 qdisc pfifo_fast
 state DOWN qlen 256
    ...
 7: mlx4_ib1.8003@mlx4_ib1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 2044 qdisc
 pfifo_fast state DOWN qlen 256
    ...

Then after connecting and disconnecting the link, which should result
in exactly the same state as before, it shows:

 5: mlx4_ib1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 2044 qdisc pfifo_fast
 state DOWN qlen 256
    ...
 7: mlx4_ib1.8003@mlx4_ib1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 2044 qdisc
 pfifo_fast state LOWERLAYERDOWN qlen 256
    ...

Notice the (now correct) LOWERLAYERDOWN operstate shown for the
mlx4_ib1.8003 interface. Ideally the identical state would be shown
right after boot.

The problem is related to the calling of netif_carrier_off() in
network drivers.  For a long time it was known that doing
netif_carrier_off() before registering the netdevice would result in
the interface's operstate being shown as UNKNOWN if the device was
brought up without a working link. This problem was fixed in commit
8f4cccbbd9 ('net: Set device operstate at registration time'), but
still there remains the minor inconsistency demonstrated above.

This patch fixes it by moving ipoib's call to netif_carrier_off() into
the .ndo_open method, which is where network drivers ordinarily do it.
With the patch when doing the same test as above, the operstate of
mlx4_ib1.8003 is shown as LOWERLAYERDOWN right after boot.

Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Acked-by: Erez Shitrit <erezsh@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/ulp/ipoib/ipoib_main.c

@@ -104,6 +104,8 @@ int ipoib_open(struct net_device *dev)
 
 	ipoib_dbg(priv, "bringing up interface\n");
 
+	netif_carrier_off(dev);
+
 	set_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags);
 
 	if (ipoib_pkey_dev_delay_open(dev))
@@ -1366,8 +1368,6 @@ void ipoib_setup(struct net_device *dev)
 
 	memcpy(dev->broadcast, ipv4_bcast_addr, INFINIBAND_ALEN);
 
-	netif_carrier_off(dev);
-
 	priv->dev = dev;
 
 	spin_lock_init(&priv->lock);