net: sched: introduce block mechanism to handle netif_keep_dst calls

Couple of classifiers call netif_keep_dst directly on q->dev. That is
not possible to do directly for shared blocke where multiple qdiscs are
owning the block. So introduce a infrastructure to keep track of the
block owners in list and use this list to implement block variant of
netif_keep_dst.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/cls_flow.c b/net/sched/cls_flow.c
index 25c2a88..28cd6fb 100644
--- a/net/sched/cls_flow.c
+++ b/net/sched/cls_flow.c
@@ -526,7 +526,7 @@ static int flow_change(struct net *net, struct sk_buff *in_skb,
 
 	timer_setup(&fnew->perturb_timer, flow_perturbation, TIMER_DEFERRABLE);
 
-	netif_keep_dst(qdisc_dev(tp->q));
+	tcf_block_netif_keep_dst(tp->chain->block);
 
 	if (tb[TCA_FLOW_KEYS]) {
 		fnew->keymask = keymask;