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Commit 6b6df466 authored by Julian Anastasov's avatar Julian Anastasov Committed by Pablo Neira Ayuso
Browse files

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: default avatarJulian Anastasov <ja@ssi.bg>
Signed-off-by: default avatarSimon Horman <horms@verge.net.au>
parent 71dfa982

include/net/ip_vs.h

+6 −0
Original line number Diff line number Diff line
@@ -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,

net/netfilter/ipvs/ip_vs_core.c

+6 −0
Original line number Diff line number Diff line
@@ -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;

net/netfilter/ipvs/ip_vs_ctl.c

+8 −0
Original line number Diff line number Diff line
@@ -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

	 */