Commit 9337057d authored Sep 29, 2010 by Boaz Harrosh Committed by David S. Miller Sep 29, 2010

um: Proper Fix for f25c80a4: remove duplicate structure field initialization



uml_net_set_mac() was broken and luckily it was never used, before.
What it was trying to do is spin_lock before memcopy the mac address.
Linus attempted to fix it in assumption that someone decided the
lock was needed. But since it was never ever used at all, and was
just dead code, I think we can assume that it is not needed, after
all.

On the other hand patch [f25c80a4] was trying to use eth_mac_addr()
in eth_configure(), *which was the real fallout*. Because of state
checks done inside eth_mac_addr() the address was never set. I have
not reintroduced the memcpy wrapper, but I've put a comment for future
cats.

The code now is back to exactly as it was before [f25c80a4]. With
the cleanup applied. If the spin_lock is indeed needed then a contender
should supply a test case that fails, then fix it with the proper
locking, as a separate unrelated patch.

CC: Julia Lawall <julia@diku.dk>
CC: David S. Miller <davem@davemloft.net>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Al Viro <viro@ZenIV.linux.org.uk>
Tested-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 68c1f3a9

arch/um/drivers/net_kern.c

+3 −14

Original line number	Diff line number	Diff line
		@@ -255,18 +255,6 @@ static void uml_net_tx_timeout(struct net_device *dev)
		netif_wake_queue(dev);
		}

		static int uml_net_set_mac(struct net_device dev, void addr)
		{
		struct uml_net_private *lp = netdev_priv(dev);
		struct sockaddr *hwaddr = addr;

		spin_lock_irq(&lp->lock);
		eth_mac_addr(dev, hwaddr->sa_data);
		spin_unlock_irq(&lp->lock);

		return 0;
		}

		static int uml_net_change_mtu(struct net_device *dev, int new_mtu)
		{
		dev->mtu = new_mtu;
		@@ -373,7 +361,7 @@ static const struct net_device_ops uml_netdev_ops = {
		.ndo_start_xmit = uml_net_start_xmit,
		.ndo_set_multicast_list = uml_net_set_multicast_list,
		.ndo_tx_timeout = uml_net_tx_timeout,
		.ndo_set_mac_address = uml_net_set_mac,
		.ndo_set_mac_address = eth_mac_addr,
		.ndo_change_mtu = uml_net_change_mtu,
		.ndo_validate_addr = eth_validate_addr,
		};
		@@ -472,7 +460,8 @@ static void eth_configure(int n, void init, char mac,
		((*transport->user->init)(&lp->user, dev) != 0))
		goto out_unregister;

		eth_mac_addr(dev, device->mac);
		/* don't use eth_mac_addr, it will not work here */
		memcpy(dev->dev_addr, device->mac, ETH_ALEN);
		dev->mtu = transport->user->mtu;
		dev->netdev_ops = &uml_netdev_ops;
		dev->ethtool_ops = &uml_net_ethtool_ops;

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