ipvs: preparations for using rcu in schedulers

Allow schedulers to use rcu_dereference when
returning destination on lookup. The RCU read-side critical
section will allow ip_vs_bind_dest to get dest refcnt as
preparation for the step where destinations will be
deleted without an IP_VS_WAIT_WHILE guard that holds the
packet processing during update.

	Add new optional scheduler methods add_dest,
del_dest and upd_dest. For now the methods are called
together with update_service but update_service will be
removed in a following change.

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
This commit is contained in:
Julian Anastasov 2013-03-22 11:46:37 +02:00 committed by Pablo Neira Ayuso
parent 71dfa982f1
commit 6b6df46663
3 changed files with 20 additions and 0 deletions

View File

@ -805,6 +805,12 @@ struct ip_vs_scheduler {
int (*done_service)(struct ip_vs_service *svc);
/* scheduler updating service */
int (*update_service)(struct ip_vs_service *svc);
/* dest is linked */
int (*add_dest)(struct ip_vs_service *svc, struct ip_vs_dest *dest);
/* dest is unlinked */
int (*del_dest)(struct ip_vs_service *svc, struct ip_vs_dest *dest);
/* dest is updated */
int (*upd_dest)(struct ip_vs_service *svc, struct ip_vs_dest *dest);
/* selecting a server from the given service */
struct ip_vs_dest* (*schedule)(struct ip_vs_service *svc,

View File

@ -301,8 +301,10 @@ ip_vs_sched_persist(struct ip_vs_service *svc,
* template is not available.
* return *ignored=0 i.e. ICMP and NF_DROP
*/
rcu_read_lock();
dest = svc->scheduler->schedule(svc, skb);
if (!dest) {
rcu_read_unlock();
IP_VS_DBG(1, "p-schedule: no dest found.\n");
kfree(param.pe_data);
*ignored = 0;
@ -318,6 +320,7 @@ ip_vs_sched_persist(struct ip_vs_service *svc,
* when the template expires */
ct = ip_vs_conn_new(&param, &dest->addr, dport,
IP_VS_CONN_F_TEMPLATE, dest, skb->mark);
rcu_read_unlock();
if (ct == NULL) {
kfree(param.pe_data);
*ignored = -1;
@ -446,8 +449,10 @@ ip_vs_schedule(struct ip_vs_service *svc, struct sk_buff *skb,
return NULL;
}
rcu_read_lock();
dest = svc->scheduler->schedule(svc, skb);
if (dest == NULL) {
rcu_read_unlock();
IP_VS_DBG(1, "Schedule: no dest found.\n");
return NULL;
}
@ -468,6 +473,7 @@ ip_vs_schedule(struct ip_vs_service *svc, struct sk_buff *skb,
cp = ip_vs_conn_new(&p, &dest->addr,
dest->port ? dest->port : pptr[1],
flags, dest, skb->mark);
rcu_read_unlock();
if (!cp) {
*ignored = -1;
return NULL;

View File

@ -825,6 +825,11 @@ __ip_vs_update_dest(struct ip_vs_service *svc, struct ip_vs_dest *dest,
if (add) {
list_add(&dest->n_list, &svc->destinations);
svc->num_dests++;
if (svc->scheduler->add_dest)
svc->scheduler->add_dest(svc, dest);
} else {
if (svc->scheduler->upd_dest)
svc->scheduler->upd_dest(svc, dest);
}
/* call the update_service, because server weight may be changed */
@ -1071,6 +1076,9 @@ static void __ip_vs_unlink_dest(struct ip_vs_service *svc,
list_del(&dest->n_list);
svc->num_dests--;
if (svcupd && svc->scheduler->del_dest)
svc->scheduler->del_dest(svc, dest);
/*
* Call the update_service function of its scheduler
*/