[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/tg3.c b/drivers/net/tg3.c
index 26c6ac4..8c8f9f4 100644
--- a/drivers/net/tg3.c
+++ b/drivers/net/tg3.c
@@ -9114,8 +9114,7 @@
 		tg3_netif_stop(tp);
 
 	tg3_full_lock(tp, 0);
-	if (tp->vlgrp)
-		tp->vlgrp->vlan_devices[vid] = NULL;
+	vlan_group_set_device(tp->vlgrp, vid, NULL);
 	tg3_full_unlock(tp);
 
 	if (netif_running(dev))