ipv4: Calling ->cow_metrics() now is a bug. (31248731) · Commits · 戴 / test

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:

David S. Miller <davem@davemloft.net>

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,

Admin message