1 files changed, 29 insertions, 34 deletions

diff --git a/net/netfilter/ipvs/ip_vs_sched.c b/net/netfilter/ipvs/ip_vs_sched.c
index d6bf20d6cdbe..4dbcda6258bc 100644
--- a/net/netfilter/ipvs/ip_vs_sched.c
+++ b/net/netfilter/ipvs/ip_vs_sched.c
@@ -35,8 +35,8 @@ EXPORT_SYMBOL(ip_vs_scheduler_err);
  */
 static LIST_HEAD(ip_vs_schedulers);
 
-/* lock for service table */
-static DEFINE_SPINLOCK(ip_vs_sched_lock);
+/* semaphore for schedulers */
+static DEFINE_MUTEX(ip_vs_sched_mutex);
 
 
 /*
@@ -47,8 +47,6 @@ int ip_vs_bind_scheduler(struct ip_vs_service *svc,
 {
 	int ret;
 
-	svc->scheduler = scheduler;
-
 	if (scheduler->init_service) {
 		ret = scheduler->init_service(svc);
 		if (ret) {
@@ -56,7 +54,7 @@ int ip_vs_bind_scheduler(struct ip_vs_service *svc,
 			return ret;
 		}
 	}
-
+	rcu_assign_pointer(svc->scheduler, scheduler);
 	return 0;
 }
 
@@ -64,22 +62,19 @@ int ip_vs_bind_scheduler(struct ip_vs_service *svc,
 /*
  *  Unbind a service with its scheduler
  */
-int ip_vs_unbind_scheduler(struct ip_vs_service *svc)
+void ip_vs_unbind_scheduler(struct ip_vs_service *svc,
+			    struct ip_vs_scheduler *sched)
 {
-	struct ip_vs_scheduler *sched = svc->scheduler;
+	struct ip_vs_scheduler *cur_sched;
 
-	if (!sched)
-		return 0;
+	cur_sched = rcu_dereference_protected(svc->scheduler, 1);
+	/* This check proves that old 'sched' was installed */
+	if (!cur_sched)
+		return;
 
-	if (sched->done_service) {
-		if (sched->done_service(svc) != 0) {
-			pr_err("%s(): done error\n", __func__);
-			return -EINVAL;
-		}
-	}
-
-	svc->scheduler = NULL;
-	return 0;
+	if (sched->done_service)
+		sched->done_service(svc);
+	/* svc->scheduler can not be set to NULL */
 }
 
 
@@ -92,7 +87,7 @@ static struct ip_vs_scheduler *ip_vs_sched_getbyname(const char *sched_name)
 
 	IP_VS_DBG(2, "%s(): sched_name \"%s\"\n", __func__, sched_name);
 
-	spin_lock_bh(&ip_vs_sched_lock);
+	mutex_lock(&ip_vs_sched_mutex);
 
 	list_for_each_entry(sched, &ip_vs_schedulers, n_list) {
 		/*
@@ -106,14 +101,14 @@ static struct ip_vs_scheduler *ip_vs_sched_getbyname(const char *sched_name)
 		}
 		if (strcmp(sched_name, sched->name)==0) {
 			/* HIT */
-			spin_unlock_bh(&ip_vs_sched_lock);
+			mutex_unlock(&ip_vs_sched_mutex);
 			return sched;
 		}
 		if (sched->module)
 			module_put(sched->module);
 	}
 
-	spin_unlock_bh(&ip_vs_sched_lock);
+	mutex_unlock(&ip_vs_sched_mutex);
 	return NULL;
 }
 
@@ -153,21 +148,21 @@ void ip_vs_scheduler_put(struct ip_vs_scheduler *scheduler)
 
 void ip_vs_scheduler_err(struct ip_vs_service *svc, const char *msg)
 {
+	struct ip_vs_scheduler *sched;
+
+	sched = rcu_dereference(svc->scheduler);
 	if (svc->fwmark) {
 		IP_VS_ERR_RL("%s: FWM %u 0x%08X - %s\n",
-			     svc->scheduler->name, svc->fwmark,
-			     svc->fwmark, msg);
+			     sched->name, svc->fwmark, svc->fwmark, msg);
 #ifdef CONFIG_IP_VS_IPV6
 	} else if (svc->af == AF_INET6) {
 		IP_VS_ERR_RL("%s: %s [%pI6c]:%d - %s\n",
-			     svc->scheduler->name,
-			     ip_vs_proto_name(svc->protocol),
+			     sched->name, ip_vs_proto_name(svc->protocol),
 			     &svc->addr.in6, ntohs(svc->port), msg);
 #endif
 	} else {
 		IP_VS_ERR_RL("%s: %s %pI4:%d - %s\n",
-			     svc->scheduler->name,
-			     ip_vs_proto_name(svc->protocol),
+			     sched->name, ip_vs_proto_name(svc->protocol),
 			     &svc->addr.ip, ntohs(svc->port), msg);
 	}
 }
@@ -192,10 +187,10 @@ int register_ip_vs_scheduler(struct ip_vs_scheduler *scheduler)
 	/* increase the module use count */
 	ip_vs_use_count_inc();
 
-	spin_lock_bh(&ip_vs_sched_lock);
+	mutex_lock(&ip_vs_sched_mutex);
 
 	if (!list_empty(&scheduler->n_list)) {
-		spin_unlock_bh(&ip_vs_sched_lock);
+		mutex_unlock(&ip_vs_sched_mutex);
 		ip_vs_use_count_dec();
 		pr_err("%s(): [%s] scheduler already linked\n",
 		       __func__, scheduler->name);
@@ -208,7 +203,7 @@ int register_ip_vs_scheduler(struct ip_vs_scheduler *scheduler)
 	 */
 	list_for_each_entry(sched, &ip_vs_schedulers, n_list) {
 		if (strcmp(scheduler->name, sched->name) == 0) {
-			spin_unlock_bh(&ip_vs_sched_lock);
+			mutex_unlock(&ip_vs_sched_mutex);
 			ip_vs_use_count_dec();
 			pr_err("%s(): [%s] scheduler already existed "
 			       "in the system\n", __func__, scheduler->name);
@@ -219,7 +214,7 @@ int register_ip_vs_scheduler(struct ip_vs_scheduler *scheduler)
 	 *	Add it into the d-linked scheduler list
 	 */
 	list_add(&scheduler->n_list, &ip_vs_schedulers);
-	spin_unlock_bh(&ip_vs_sched_lock);
+	mutex_unlock(&ip_vs_sched_mutex);
 
 	pr_info("[%s] scheduler registered.\n", scheduler->name);
 
@@ -237,9 +232,9 @@ int unregister_ip_vs_scheduler(struct ip_vs_scheduler *scheduler)
 		return -EINVAL;
 	}
 
-	spin_lock_bh(&ip_vs_sched_lock);
+	mutex_lock(&ip_vs_sched_mutex);
 	if (list_empty(&scheduler->n_list)) {
-		spin_unlock_bh(&ip_vs_sched_lock);
+		mutex_unlock(&ip_vs_sched_mutex);
 		pr_err("%s(): [%s] scheduler is not in the list. failed\n",
 		       __func__, scheduler->name);
 		return -EINVAL;
@@ -249,7 +244,7 @@ int unregister_ip_vs_scheduler(struct ip_vs_scheduler *scheduler)
 	 *	Remove it from the d-linked scheduler list
 	 */
 	list_del(&scheduler->n_list);
-	spin_unlock_bh(&ip_vs_sched_lock);
+	mutex_unlock(&ip_vs_sched_mutex);
 
 	/* decrease the module use count */
 	ip_vs_use_count_dec();