[VLAN]: Avoid a 4-order allocation.

This patch splits the vlan_group struct into a multi-allocated struct. On
x86_64, the size of the original struct is a little more than 32KB, causing
a 4-order allocation, which is prune to problems caused by buddy-system
external fragmentation conditions.

I couldn't just use vmalloc() because vfree() cannot be called in the
softirq context of the RCU callback.

Signed-off-by: Dan Aloni <da-x@monatomic.org>
Acked-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/s2io.c b/drivers/net/s2io.c
index 44bb239..46ebf141 100644
--- a/drivers/net/s2io.c
+++ b/drivers/net/s2io.c
@@ -325,8 +325,7 @@
 	unsigned long flags;
 
 	spin_lock_irqsave(&nic->tx_lock, flags);
-	if (nic->vlgrp)
-		nic->vlgrp->vlan_devices[vid] = NULL;
+	vlan_group_set_device(nic->vlgrp, vid, NULL);
 	spin_unlock_irqrestore(&nic->tx_lock, flags);
 }