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Commit 31248731 authored by David S. Miller's avatar David S. Miller
Browse files

ipv4: Calling ->cow_metrics() now is a bug. 



Nothing every writes to ipv4 metrics any longer.

PMTU is stored in rt->rt_pmtu.

Dynamic TCP metrics are stored in a special TCP metrics cache,
completely outside of the routes.

Therefore ->cow_metrics() can simply nothing more than a WARN_ON
trigger so we can catch anyone who tries to add new writes to
ipv4 route metrics.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2db2d67e

net/ipv4/route.c

+2 −28
Original line number Diff line number Diff line
@@ -158,34 +158,8 @@ static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev, 


static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)

{

	struct rtable *rt = (struct rtable *) dst;

	struct inet_peer *peer;

	u32 *p = NULL;



	peer = rt_get_peer_create(rt, rt->rt_dst);

	if (peer) {

		u32 *old_p = __DST_METRICS_PTR(old);

		unsigned long prev, new;



		p = peer->metrics;

		if (inet_metrics_new(peer))

			memcpy(p, old_p, sizeof(u32) * RTAX_MAX);



		new = (unsigned long) p;

		prev = cmpxchg(&dst->_metrics, old, new);



		if (prev != old) {

			p = __DST_METRICS_PTR(prev);

			if (prev & DST_METRICS_READ_ONLY)

				p = NULL;

		} else {

			if (rt->fi) {

				fib_info_put(rt->fi);

				rt->fi = NULL;

			}

		}

	}

	return p;

	WARN_ON(1);

	return NULL;

}



static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,