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: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 28 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index a967df54a423..9cc00f8a6ee5 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -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,