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ipvs: convert locks used in persistence engines

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Allow the readers to use RCU lock and for
PE module registrations use global mutex instead of
spinlock. All PE modules need to use synchronize_rcu
in their module exit handler.

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>
This commit is contained in:
Julian Anastasov 2013-03-21 11:58:09 +02:00 committed by Pablo Neira Ayuso
parent 276472eae0
commit 60b6aa3b31
2 changed files with 14 additions and 30 deletions
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43
net/netfilter/ipvs/ip_vs_pe.c
View File

@ -13,8 +13,8 @@
/* IPVS pe list */
static LIST_HEAD(ip_vs_pe);
/* lock for service table */
static DEFINE_SPINLOCK(ip_vs_pe_lock);
/* semaphore for IPVS PEs. */
static DEFINE_MUTEX(ip_vs_pe_mutex);
/* Bind a service with a pe */
void ip_vs_bind_pe(struct ip_vs_service *svc, struct ip_vs_pe *pe)
@ -36,9 +36,8 @@ struct ip_vs_pe *__ip_vs_pe_getbyname(const char *pe_name)
IP_VS_DBG(10, "%s(): pe_name \"%s\"\n", __func__,
pe_name);
spin_lock_bh(&ip_vs_pe_lock);
list_for_each_entry(pe, &ip_vs_pe, n_list) {
rcu_read_lock();
list_for_each_entry_rcu(pe, &ip_vs_pe, n_list) {
/* Test and get the modules atomically */
if (pe->module &&
!try_module_get(pe->module)) {
@ -47,14 +46,14 @@ struct ip_vs_pe *__ip_vs_pe_getbyname(const char *pe_name)
}
if (strcmp(pe_name, pe->name)==0) {
/* HIT */
spin_unlock_bh(&ip_vs_pe_lock);
rcu_read_unlock();
return pe;
}
if (pe->module)
module_put(pe->module);
}
rcu_read_unlock();
spin_unlock_bh(&ip_vs_pe_lock);
return NULL;
}
@ -83,22 +82,13 @@ int register_ip_vs_pe(struct ip_vs_pe *pe)
/* increase the module use count */
ip_vs_use_count_inc();
spin_lock_bh(&ip_vs_pe_lock);
if (!list_empty(&pe->n_list)) {
spin_unlock_bh(&ip_vs_pe_lock);
ip_vs_use_count_dec();
pr_err("%s(): [%s] pe already linked\n",
__func__, pe->name);
return -EINVAL;
}
mutex_lock(&ip_vs_pe_mutex);
/* Make sure that the pe with this name doesn't exist
* in the pe list.
*/
list_for_each_entry(tmp, &ip_vs_pe, n_list) {
if (strcmp(tmp->name, pe->name) == 0) {
spin_unlock_bh(&ip_vs_pe_lock);
mutex_unlock(&ip_vs_pe_mutex);
ip_vs_use_count_dec();
pr_err("%s(): [%s] pe already existed "
"in the system\n", __func__, pe->name);
@ -106,8 +96,8 @@ int register_ip_vs_pe(struct ip_vs_pe *pe)
}
}
/* Add it into the d-linked pe list */
list_add(&pe->n_list, &ip_vs_pe);
spin_unlock_bh(&ip_vs_pe_lock);
list_add_rcu(&pe->n_list, &ip_vs_pe);
mutex_unlock(&ip_vs_pe_mutex);
pr_info("[%s] pe registered.\n", pe->name);
@ -118,17 +108,10 @@ EXPORT_SYMBOL_GPL(register_ip_vs_pe);
/* Unregister a pe from the pe list */
int unregister_ip_vs_pe(struct ip_vs_pe *pe)
{
spin_lock_bh(&ip_vs_pe_lock);
if (list_empty(&pe->n_list)) {
spin_unlock_bh(&ip_vs_pe_lock);
pr_err("%s(): [%s] pe is not in the list. failed\n",
__func__, pe->name);
return -EINVAL;
}
mutex_lock(&ip_vs_pe_mutex);
/* Remove it from the d-linked pe list */
list_del(&pe->n_list);
spin_unlock_bh(&ip_vs_pe_lock);
list_del_rcu(&pe->n_list);
mutex_unlock(&ip_vs_pe_mutex);
/* decrease the module use count */
ip_vs_use_count_dec();

1
net/netfilter/ipvs/ip_vs_pe_sip.c
View File

@ -172,6 +172,7 @@ static int __init ip_vs_sip_init(void)
static void __exit ip_vs_sip_cleanup(void)
{
unregister_ip_vs_pe(&ip_vs_sip_pe);
synchronize_rcu();
}
module_init(ip_vs_sip_init);