ipvs: convert services to rcu

This is the final step in RCU conversion.

Things that are removed:

- svc->usecnt: now svc is accessed under RCU read lock
- svc->inc: and some unused code
- ip_vs_bind_pe and ip_vs_unbind_pe: no ability to replace PE
- __ip_vs_svc_lock: replaced with RCU
- IP_VS_WAIT_WHILE: now readers lookup svcs and dests under
	RCU and work in parallel with configuration

Other changes:

- before now, a RCU read-side critical section included the
calling of the schedule method, now it is extended to include
service lookup
- ip_vs_svc_table and ip_vs_svc_fwm_table are now using hlist
- svc->pe and svc->scheduler remain to the end (of grace period),
	the schedulers are prepared for such RCU readers
	even after done_service is called but they need
	to use synchronize_rcu because last ip_vs_scheduler_put
	can happen while RCU read-side critical sections
	use an outdated svc->scheduler pointer
- as planned, update_service is removed
- empty services can be freed immediately after grace period.
	If dests were present, the services are freed from
	the dest trash code

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>

1 files changed, 7 insertions, 7 deletions

diff --git a/net/netfilter/ipvs/ip_vs_proto_tcp.c b/net/netfilter/ipvs/ip_vs_proto_tcp.c
index 0bbc3feae682..7de3342e9797 100644
--- a/net/netfilter/ipvs/ip_vs_proto_tcp.c
+++ b/net/netfilter/ipvs/ip_vs_proto_tcp.c
@@ -47,9 +47,10 @@ tcp_conn_schedule(int af, struct sk_buff *skb, struct ip_vs_proto_data *pd,
 	}
 	net = skb_net(skb);
 	/* No !th->ack check to allow scheduling on SYN+ACK for Active FTP */
+	rcu_read_lock();
 	if (th->syn &&
-	    (svc = ip_vs_service_get(net, af, skb->mark, iph->protocol,
-				     &iph->daddr, th->dest))) {
+	    (svc = ip_vs_service_find(net, af, skb->mark, iph->protocol,
+				      &iph->daddr, th->dest))) {
 		int ignored;
 
 		if (ip_vs_todrop(net_ipvs(net))) {
@@ -57,7 +58,7 @@ tcp_conn_schedule(int af, struct sk_buff *skb, struct ip_vs_proto_data *pd,
 			 * It seems that we are very loaded.
 			 * We have to drop this packet :(
 			 */
-			ip_vs_service_put(svc);
+			rcu_read_unlock();
 			*verdict = NF_DROP;
 			return 0;
 		}
@@ -70,14 +71,13 @@ tcp_conn_schedule(int af, struct sk_buff *skb, struct ip_vs_proto_data *pd,
 		if (!*cpp && ignored <= 0) {
 			if (!ignored)
 				*verdict = ip_vs_leave(svc, skb, pd, iph);
-			else {
-				ip_vs_service_put(svc);
+			else
 				*verdict = NF_DROP;
-			}
+			rcu_read_unlock();
 			return 0;
 		}
-		ip_vs_service_put(svc);
 	}
+	rcu_read_unlock();
 	/* NF_ACCEPT */
 	return 1;
 }