ipsec: pfkey should ignore events when no listeners

Jamal Hadi Salim · davem330 · commit 99c6f60e72f1 · 2008-06-10T14:25:34.000-07:00
When pfkey has no km listeners, it still does a lot of work
before finding out there aint nobody out there.
If a tree falls in a forest and no one is around to hear it, does it make
a sound? In this case it makes a lot of noise:
With this short-circuit adding 10s of thousands of SAs using
netlink improves performance by ~10%.

Signed-off-by: Jamal Hadi Salim &lt;hadi@cyberus.ca&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
diff --git a/net/key/af_key.c b/net/key/af_key.c
@@ -3030,6 +3030,9 @@ static int key_notify_sa_expire(struct xfrm_state *x, struct km_event *c)
 
 static int pfkey_send_notify(struct xfrm_state *x, struct km_event *c)
 {
+	if (atomic_read(&pfkey_socks_nr) == 0)
+		return 0;
+
 	switch (c->event) {
 	case XFRM_MSG_EXPIRE:
 		return key_notify_sa_expire(x, c);

Original file line number	Diff line number	Diff line change
`@@ -3030,6 +3030,9 @@ static int key_notify_sa_expire(struct xfrm_state x, struct km_event c)`
`3030`	`3030`
`3031`	`3031`	`static int pfkey_send_notify(struct xfrm_state x, struct km_event c)`
`3032`	`3032`	`{`
	`3033`	`+ if (atomic_read(&pfkey_socks_nr) == 0)`
	`3034`	`+ return 0;`
	`3035`	`+`
`3033`	`3036`	`switch (c->event) {`
`3034`	`3037`	`case XFRM_MSG_EXPIRE:`
`3035`	`3038`	`return key_notify_sa_expire(x, c);`