ipv4: Allocate fib metrics dynamically.

This is the initial gateway towards super-sharing metrics
if they are all set to zero for a route.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/ip_fib.h

@@ -77,7 +77,7 @@ struct fib_info {
 	int			fib_protocol;
 	__be32			fib_prefsrc;
 	u32			fib_priority;
-	u32			fib_metrics[RTAX_MAX];
+	u32			*fib_metrics;
 #define fib_mtu fib_metrics[RTAX_MTU-1]
 #define fib_window fib_metrics[RTAX_WINDOW-1]
 #define fib_rtt fib_metrics[RTAX_RTT-1]

net/ipv4/fib_semantics.c

@@ -152,6 +152,7 @@ static void free_fib_info_rcu(struct rcu_head *head)
 {
 	struct fib_info *fi = container_of(head, struct fib_info, rcu);
 
+	kfree(fi->fib_metrics);
 	kfree(fi);
 }
 
@@ -742,6 +743,9 @@ struct fib_info *fib_create_info(struct fib_config *cfg)
 	fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct fib_nh), GFP_KERNEL);
 	if (fi == NULL)
 		goto failure;
+	fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL);
+	if (!fi->fib_metrics)
+		goto failure;
 	fib_info_cnt++;
 
 	fi->fib_net = hold_net(net);