xfrm: Fix the gc threshold value for ipv4

The xfrm gc threshold value depends on ip_rt_max_size. This
value was set to INT_MAX with the routing cache removal patch,
so we start doing garbage collecting when we have INT_MAX/2
IPsec routes cached. Fix this by going back to the static
threshold of 1024 routes.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

include/net/xfrm.h

@@ -1351,7 +1351,7 @@ struct xfrm6_tunnel {
 };
 
 extern void xfrm_init(void);
-extern void xfrm4_init(int rt_hash_size);
+extern void xfrm4_init(void);
 extern int xfrm_state_init(struct net *net);
 extern void xfrm_state_fini(struct net *net);
 extern void xfrm4_state_init(void);

net/ipv4/route.c

@@ -2597,7 +2597,7 @@ int __init ip_rt_init(void)
 		pr_err("Unable to create route proc files\n");
 #ifdef CONFIG_XFRM
 	xfrm_init();
-	xfrm4_init(ip_rt_max_size);
+	xfrm4_init();
 #endif
 	rtnl_register(PF_INET, RTM_GETROUTE, inet_rtm_getroute, NULL, NULL);
 

net/ipv4/xfrm4_policy.c

@@ -279,19 +279,8 @@ static void __exit xfrm4_policy_fini(void)
 	xfrm_policy_unregister_afinfo(&xfrm4_policy_afinfo);
 }
 
-void __init xfrm4_init(int rt_max_size)
+void __init xfrm4_init(void)
 {
-	/*
-	 * Select a default value for the gc_thresh based on the main route
-	 * table hash size.  It seems to me the worst case scenario is when
-	 * we have ipsec operating in transport mode, in which we create a
-	 * dst_entry per socket.  The xfrm gc algorithm starts trying to remove
-	 * entries at gc_thresh, and prevents new allocations as 2*gc_thresh
-	 * so lets set an initial xfrm gc_thresh value at the rt_max_size/2.
-	 * That will let us store an ipsec connection per route table entry,
-	 * and start cleaning when were 1/2 full
-	 */
-	xfrm4_dst_ops.gc_thresh = rt_max_size/2;
 	dst_entries_init(&xfrm4_dst_ops);
 
 	xfrm4_state_init();