ipvs: convert app locks
We use locks like tcp_app_lock, udp_app_lock,
sctp_app_lock to protect access to the protocol hash tables
from readers in packet context while the application
instances (inc) are [un]registered under global mutex.
As the hash tables are mostly read when conns are
created and bound to app, use RCU for readers and reclaim
app instance after grace period.
Simplify ip_vs_app_inc_get because we use usecnt
only for statistics and rely on module refcounting.
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off by: Hans Schillstrom <hans@schillstrom.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
diff --git a/net/netfilter/ipvs/ip_vs_app.c b/net/netfilter/ipvs/ip_vs_app.c
index 0b779d7..a956030 100644
--- a/net/netfilter/ipvs/ip_vs_app.c
+++ b/net/netfilter/ipvs/ip_vs_app.c
@@ -58,6 +58,18 @@
module_put(app->module);
}
+static void ip_vs_app_inc_destroy(struct ip_vs_app *inc)
+{
+ kfree(inc->timeout_table);
+ kfree(inc);
+}
+
+static void ip_vs_app_inc_rcu_free(struct rcu_head *head)
+{
+ struct ip_vs_app *inc = container_of(head, struct ip_vs_app, rcu_head);
+
+ ip_vs_app_inc_destroy(inc);
+}
/*
* Allocate/initialize app incarnation and register it in proto apps.
@@ -106,8 +118,7 @@
return 0;
out:
- kfree(inc->timeout_table);
- kfree(inc);
+ ip_vs_app_inc_destroy(inc);
return ret;
}
@@ -131,8 +142,7 @@
list_del(&inc->a_list);
- kfree(inc->timeout_table);
- kfree(inc);
+ call_rcu(&inc->rcu_head, ip_vs_app_inc_rcu_free);
}
@@ -144,9 +154,9 @@
{
int result;
- atomic_inc(&inc->usecnt);
- if (unlikely((result = ip_vs_app_get(inc->app)) != 1))
- atomic_dec(&inc->usecnt);
+ result = ip_vs_app_get(inc->app);
+ if (result)
+ atomic_inc(&inc->usecnt);
return result;
}
@@ -156,8 +166,8 @@
*/
void ip_vs_app_inc_put(struct ip_vs_app *inc)
{
- ip_vs_app_put(inc->app);
atomic_dec(&inc->usecnt);
+ ip_vs_app_put(inc->app);
}
@@ -218,6 +228,7 @@
/*
* ip_vs_app unregistration routine
* We are sure there are no app incarnations attached to services
+ * Caller should use synchronize_rcu() or rcu_barrier()
*/
void unregister_ip_vs_app(struct net *net, struct ip_vs_app *app)
{