Merge branch 'tipc-subscription-refcount-simplifications'

Parthasarathy Bhuvaragan says:

====================
tipc: subscription refcount simplifications

The first patch makes the subscription refcount cleanup lockless and
the second updates the subscription refcount policy.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/tipc/name_table.c

@@ -416,6 +416,7 @@ static void tipc_nameseq_subscribe(struct name_seq *nseq,
 
 	tipc_subscrp_convert_seq(&s->evt.s.seq, s->swap, &ns);
 
+	tipc_subscrp_get(s);
 	list_add(&s->nameseq_list, &nseq->subscriptions);
 
 	if (!sseq)
@@ -787,6 +788,7 @@ void tipc_nametbl_unsubscribe(struct tipc_subscription *s)
 	if (seq != NULL) {
 		spin_lock_bh(&seq->lock);
 		list_del_init(&s->nameseq_list);
+		tipc_subscrp_put(s);
 		if (!seq->first_free && list_empty(&seq->subscriptions)) {
 			hlist_del_init_rcu(&seq->ns_list);
 			kfree(seq->sseqs);

net/tipc/subscr.c

@@ -54,8 +54,6 @@ struct tipc_subscriber {
 
 static void tipc_subscrp_delete(struct tipc_subscription *sub);
 static void tipc_subscrb_put(struct tipc_subscriber *subscriber);
-static void tipc_subscrp_put(struct tipc_subscription *subscription);
-static void tipc_subscrp_get(struct tipc_subscription *subscription);
 
 /**
  * htohl - convert value to endianness used by destination
@@ -125,7 +123,6 @@ void tipc_subscrp_report_overlap(struct tipc_subscription *sub, u32 found_lower,
 {
 	struct tipc_name_seq seq;
 
-	tipc_subscrp_get(sub);
 	tipc_subscrp_convert_seq(&sub->evt.s.seq, sub->swap, &seq);
 	if (!tipc_subscrp_check_overlap(&seq, found_lower, found_upper))
 		return;
@@ -135,7 +132,6 @@ void tipc_subscrp_report_overlap(struct tipc_subscription *sub, u32 found_lower,
 
 	tipc_subscrp_send_event(sub, found_lower, found_upper, event, port_ref,
 				node);
-	tipc_subscrp_put(sub);
 }
 
 static void tipc_subscrp_timeout(unsigned long data)
@@ -145,6 +141,7 @@ static void tipc_subscrp_timeout(unsigned long data)
 
 	spin_lock_bh(&subscriber->lock);
 	tipc_nametbl_unsubscribe(sub);
+	list_del(&sub->subscrp_list);
 	spin_unlock_bh(&subscriber->lock);
 
 	/* Notify subscriber of timeout */
@@ -177,20 +174,17 @@ static void tipc_subscrp_kref_release(struct kref *kref)
 	struct tipc_net *tn = net_generic(sub->net, tipc_net_id);
 	struct tipc_subscriber *subscriber = sub->subscriber;
 
-	spin_lock_bh(&subscriber->lock);
-	list_del(&sub->subscrp_list);
 	atomic_dec(&tn->subscription_count);
-	spin_unlock_bh(&subscriber->lock);
 	kfree(sub);
 	tipc_subscrb_put(subscriber);
 }
 
-static void tipc_subscrp_put(struct tipc_subscription *subscription)
+void tipc_subscrp_put(struct tipc_subscription *subscription)
 {
 	kref_put(&subscription->kref, tipc_subscrp_kref_release);
 }
 
-static void tipc_subscrp_get(struct tipc_subscription *subscription)
+void tipc_subscrp_get(struct tipc_subscription *subscription)
 {
 	kref_get(&subscription->kref);
 }
@@ -210,11 +204,8 @@ static void tipc_subscrb_subscrp_delete(struct tipc_subscriber *subscriber,
 			continue;
 
 		tipc_nametbl_unsubscribe(sub);
-		tipc_subscrp_get(sub);
-		spin_unlock_bh(&subscriber->lock);
+		list_del(&sub->subscrp_list);
 		tipc_subscrp_delete(sub);
-		tipc_subscrp_put(sub);
-		spin_lock_bh(&subscriber->lock);
 
 		if (s)
 			break;

net/tipc/subscr.h

@@ -78,4 +78,7 @@ u32 tipc_subscrp_convert_seq_type(u32 type, int swap);
 int tipc_topsrv_start(struct net *net);
 void tipc_topsrv_stop(struct net *net);
 
+void tipc_subscrp_put(struct tipc_subscription *subscription);
+void tipc_subscrp_get(struct tipc_subscription *subscription);
+
 #endif