Signed-off-by: Simon Horman <horms@xxxxxxxxxxxx>
---
I'm still getting my head around RCU, so review would be greatly appreciated.
It occurs to me that this code is not performance critical, so
perhaps simply replacing the rwlock with a spinlock would be better?
Index: nf-next-2.6/net/netfilter/ipvs/ip_vs_sched.c
===================================================================
--- nf-next-2.6.orig/net/netfilter/ipvs/ip_vs_sched.c 2010-08-20 22:21:01.000000000 +0900
+++ nf-next-2.6/net/netfilter/ipvs/ip_vs_sched.c 2010-08-20 22:21:51.000000000 +0900
@@ -35,7 +35,7 @@
static LIST_HEAD(ip_vs_schedulers);
/* lock for service table */
-static DEFINE_RWLOCK(__ip_vs_sched_lock);
+static DEFINE_SPINLOCK(ip_vs_sched_mutex);
/*
@@ -91,9 +91,9 @@ static struct ip_vs_scheduler *ip_vs_sch
IP_VS_DBG(2, "%s(): sched_name \"%s\"\n", __func__, sched_name);
- read_lock_bh(&__ip_vs_sched_lock);
+ rcu_read_lock_bh();
- list_for_each_entry(sched, &ip_vs_schedulers, n_list) {
+ list_for_each_entry_rcu(sched, &ip_vs_schedulers, n_list) {
/*
* Test and get the modules atomically
*/
@@ -105,14 +105,14 @@ static struct ip_vs_scheduler *ip_vs_sch
}
if (strcmp(sched_name, sched->name)==0) {
/* HIT */
- read_unlock_bh(&__ip_vs_sched_lock);
+ rcu_read_unlock_bh();
return sched;
}
if (sched->module)
module_put(sched->module);
}
- read_unlock_bh(&__ip_vs_sched_lock);
+ rcu_read_unlock_bh();
return NULL;
}
@@ -167,10 +167,10 @@ int register_ip_vs_scheduler(struct ip_v
/* increase the module use count */
ip_vs_use_count_inc();
- write_lock_bh(&__ip_vs_sched_lock);
+ spin_lock_bh(&ip_vs_sched_mutex);
if (!list_empty(&scheduler->n_list)) {
- write_unlock_bh(&__ip_vs_sched_lock);
+ spin_unlock_bh(&ip_vs_sched_mutex);
ip_vs_use_count_dec();
pr_err("%s(): [%s] scheduler already linked\n",
__func__, scheduler->name);
@@ -181,9 +181,9 @@ int register_ip_vs_scheduler(struct ip_v
* Make sure that the scheduler with this name doesn't exist
* in the scheduler list.
*/
- list_for_each_entry(sched, &ip_vs_schedulers, n_list) {
+ list_for_each_entry_rcu(sched, &ip_vs_schedulers, n_list) {
if (strcmp(scheduler->name, sched->name) == 0) {
- write_unlock_bh(&__ip_vs_sched_lock);
+ spin_unlock_bh(&ip_vs_sched_mutex);
ip_vs_use_count_dec();
pr_err("%s(): [%s] scheduler already existed "
"in the system\n", __func__, scheduler->name);
@@ -193,8 +193,8 @@ int register_ip_vs_scheduler(struct ip_v
/*
* Add it into the d-linked scheduler list
*/
- list_add(&scheduler->n_list, &ip_vs_schedulers);
- write_unlock_bh(&__ip_vs_sched_lock);
+ list_add_rcu(&scheduler->n_list, &ip_vs_schedulers);
+ spin_unlock_bh(&ip_vs_sched_mutex);
pr_info("[%s] scheduler registered.\n", scheduler->name);
@@ -212,9 +212,9 @@ int unregister_ip_vs_scheduler(struct ip
return -EINVAL;
}
- write_lock_bh(&__ip_vs_sched_lock);
+ spin_lock_bh(&ip_vs_sched_mutex);
if (list_empty(&scheduler->n_list)) {
- write_unlock_bh(&__ip_vs_sched_lock);
+ spin_unlock_bh(&ip_vs_sched_mutex);
pr_err("%s(): [%s] scheduler is not in the list. failed\n",
__func__, scheduler->name);
return -EINVAL;
@@ -223,8 +223,8 @@ int unregister_ip_vs_scheduler(struct ip
/*
* Remove it from the d-linked scheduler list
*/
- list_del(&scheduler->n_list);
- write_unlock_bh(&__ip_vs_sched_lock);
+ list_del_rcu(&scheduler->n_list);
+ spin_unlock_bh(&ip_vs_sched_mutex);
/* decrease the module use count */
ip_vs_use_count_dec();
--
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