[NET]: Rework dev_base via list_head (v3)

Cleanup of dev_base list use, with the aim to simplify making device
list per-namespace. In almost every occasion, use of dev_base variable
and dev->next pointer could be easily replaced by for_each_netdev
loop. A few most complicated places were converted to using
first_netdev()/next_netdev().

Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Acked-by: Kirill Korotaev <dev@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 8699e70..bec600a 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -894,9 +894,10 @@
 	s_idx = cb->args[0];
 	s_q_idx = q_idx = cb->args[1];
 	read_lock(&dev_base_lock);
-	for (dev=dev_base, idx=0; dev; dev = dev->next, idx++) {
+	idx = 0;
+	for_each_netdev(dev) {
 		if (idx < s_idx)
-			continue;
+			goto cont;
 		if (idx > s_idx)
 			s_q_idx = 0;
 		q_idx = 0;
@@ -910,6 +911,8 @@
 				goto done;
 			q_idx++;
 		}
+cont:
+		idx++;
 	}
 
 done: