On Wed, 16 Sep 2009 19:38:36 -0700
Greg KH [off-list ref] wrote:

+
+/**
+ * ks_net_open - open network device
+ * @netdev: The network device being opened.
+ *
+ * Called when the network device is marked active, such as a user executing
+ * 'ifconfig up' on the device.
+ */
+static int ks_net_open(struct net_device *netdev)
+{
+	struct ks_net *ks = netdev_priv(netdev);
+	int err;
+
+#define	KS_INT_FLAGS	(IRQF_DISABLED|IRQF_TRIGGER_LOW)
+	/* lock the card, even if we may not actually do anything
+	 * else at the moment.
+	 */
+	mutex_lock(&ks->lock);
+

I don't understand the purpose of ks->lock mutex. What is it
really protecting? open/close are already protected by rtnl_mutex,
is it really only for the PHY?