Commit 29e5375d authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ipv4: add (struct uncached_list)->quarantine list 



This is an optimization to keep the per-cpu lists as short as possible:

Whenever rt_flush_dev() changes one rtable dst.dev
matching the disappearing device, it can can transfer the object
to a quarantine list, waiting for a final rt_del_uncached_list().

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ba55ef81

net/ipv4/route.c

+9 −3
Original line number Diff line number Diff line
@@ -1485,6 +1485,7 @@ static bool rt_cache_route(struct fib_nh_common *nhc, struct rtable *rt) 
struct uncached_list {

	spinlock_t		lock;

	struct list_head	head;

	struct list_head	quarantine;

};



static DEFINE_PER_CPU_ALIGNED(struct uncached_list, rt_uncached_list);
@@ -1506,7 +1507,7 @@ void rt_del_uncached_list(struct rtable *rt) 
		struct uncached_list *ul = rt->rt_uncached_list;



		spin_lock_bh(&ul->lock);

		list_del(&rt->rt_uncached);

		list_del_init(&rt->rt_uncached);

		spin_unlock_bh(&ul->lock);

	}

}
@@ -1521,20 +1522,24 @@ static void ipv4_dst_destroy(struct dst_entry *dst) 


void rt_flush_dev(struct net_device *dev)

{

	struct rtable *rt;

	struct rtable *rt, *safe;

	int cpu;



	for_each_possible_cpu(cpu) {

		struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);



		if (list_empty(&ul->head))

			continue;



		spin_lock_bh(&ul->lock);

		list_for_each_entry(rt, &ul->head, rt_uncached) {

		list_for_each_entry_safe(rt, safe, &ul->head, rt_uncached) {

			if (rt->dst.dev != dev)

				continue;

			rt->dst.dev = blackhole_netdev;

			dev_replace_track(dev, blackhole_netdev,

					  &rt->dst.dev_tracker,

					  GFP_ATOMIC);

			list_move(&rt->rt_uncached, &ul->quarantine);

		}

		spin_unlock_bh(&ul->lock);

	}
@@ -3706,6 +3711,7 @@ int __init ip_rt_init(void) 
		struct uncached_list *ul = &per_cpu(rt_uncached_list, cpu);



		INIT_LIST_HEAD(&ul->head);

		INIT_LIST_HEAD(&ul->quarantine);

		spin_lock_init(&ul->lock);

	}

#ifdef CONFIG_IP_ROUTE_CLASSID