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Commit 413c2d04 authored by Julian Anastasov's avatar Julian Anastasov Committed by Pablo Neira Ayuso
Browse files

ipvs: convert dests to rcu 



In previous commits the schedulers started to access
svc->destinations with _rcu list traversal primitives
because the IP_VS_WAIT_WHILE macro still plays the role of
grace period. Now it is time to finish the updating part,
i.e. adding and deleting of dests with _rcu suffix before
removing the IP_VS_WAIT_WHILE in next commit.

We use the same rule for conns as for the
schedulers: dests can be searched in RCU read-side critical
section where ip_vs_dest_hold can be called by ip_vs_bind_dest.

Some things are not perfect, for example, calling
functions like ip_vs_lookup_dest from updating code under
RCU, just because we use some function both from reader
and from updater.

Signed-off-by: default avatarJulian Anastasov <ja@ssi.bg>
Signed-off-by: default avatarSimon Horman <horms@verge.net.au>
parent ba3a3ce1

include/net/ip_vs.h

+1 −1
Original line number Diff line number Diff line
@@ -1434,7 +1434,7 @@ extern struct ip_vs_dest * 
ip_vs_find_dest(struct net *net, int af, const union nf_inet_addr *daddr,

		__be16 dport, const union nf_inet_addr *vaddr, __be16 vport,

		__u16 protocol, __u32 fwmark, __u32 flags);

extern struct ip_vs_dest *ip_vs_try_bind_dest(struct ip_vs_conn *cp);

extern void ip_vs_try_bind_dest(struct ip_vs_conn *cp);



static inline void ip_vs_dest_hold(struct ip_vs_dest *dest)

{

net/netfilter/ipvs/ip_vs_conn.c

+5 −3
Original line number Diff line number Diff line
@@ -611,10 +611,11 @@ ip_vs_bind_dest(struct ip_vs_conn *cp, struct ip_vs_dest *dest) 
 * Check if there is a destination for the connection, if so

 * bind the connection to the destination.

 */

struct ip_vs_dest *ip_vs_try_bind_dest(struct ip_vs_conn *cp)

void ip_vs_try_bind_dest(struct ip_vs_conn *cp)

{

	struct ip_vs_dest *dest;



	rcu_read_lock();

	dest = ip_vs_find_dest(ip_vs_conn_net(cp), cp->af, &cp->daddr,

			       cp->dport, &cp->vaddr, cp->vport,

			       cp->protocol, cp->fwmark, cp->flags);
@@ -624,7 +625,8 @@ struct ip_vs_dest *ip_vs_try_bind_dest(struct ip_vs_conn *cp) 
		spin_lock(&cp->lock);

		if (cp->dest) {

			spin_unlock(&cp->lock);

			return dest;

			rcu_read_unlock();

			return;

		}



		/* Applications work depending on the forwarding method
@@ -648,7 +650,7 @@ struct ip_vs_dest *ip_vs_try_bind_dest(struct ip_vs_conn *cp) 
		if (pd && atomic_read(&pd->appcnt))

			ip_vs_bind_app(cp, pd->pp);

	}

	return dest;

	rcu_read_unlock();

}

net/netfilter/ipvs/ip_vs_ctl.c

+17 −15
Original line number Diff line number Diff line
@@ -565,8 +565,8 @@ bool ip_vs_has_real_service(struct net *net, int af, __u16 protocol, 
	return false;

}



/*

 *	Lookup destination by {addr,port} in the given service

/* Lookup destination by {addr,port} in the given service

 * Called under RCU lock.

 */

static struct ip_vs_dest *

ip_vs_lookup_dest(struct ip_vs_service *svc, const union nf_inet_addr *daddr,
@@ -577,7 +577,7 @@ ip_vs_lookup_dest(struct ip_vs_service *svc, const union nf_inet_addr *daddr, 
	/*

	 * Find the destination for the given service

	 */

	list_for_each_entry(dest, &svc->destinations, n_list) {

	list_for_each_entry_rcu(dest, &svc->destinations, n_list) {

		if ((dest->af == svc->af)

		    && ip_vs_addr_equal(svc->af, &dest->addr, daddr)

		    && (dest->port == dport)) {
@@ -591,10 +591,11 @@ ip_vs_lookup_dest(struct ip_vs_service *svc, const union nf_inet_addr *daddr, 


/*

 * Find destination by {daddr,dport,vaddr,protocol}

 * Cretaed to be used in ip_vs_process_message() in

 * Created to be used in ip_vs_process_message() in

 * the backup synchronization daemon. It finds the

 * destination to be bound to the received connection

 * on the backup.

 * Called under RCU lock, no refcnt is returned.

 */

struct ip_vs_dest *ip_vs_find_dest(struct net  *net, int af,

				   const union nf_inet_addr *daddr,
@@ -615,8 +616,6 @@ struct ip_vs_dest *ip_vs_find_dest(struct net *net, int af, 
	dest = ip_vs_lookup_dest(svc, daddr, port);

	if (!dest)

		dest = ip_vs_lookup_dest(svc, daddr, port ^ dport);

	if (dest)

		ip_vs_dest_hold(dest);

	ip_vs_service_put(svc);

	return dest;

}
@@ -826,7 +825,7 @@ __ip_vs_update_dest(struct ip_vs_service *svc, struct ip_vs_dest *dest, 
	IP_VS_WAIT_WHILE(atomic_read(&svc->usecnt) > 0);



	if (add) {

		list_add(&dest->n_list, &svc->destinations);

		list_add_rcu(&dest->n_list, &svc->destinations);

		svc->num_dests++;

		if (svc->scheduler->add_dest)

			svc->scheduler->add_dest(svc, dest);
@@ -933,10 +932,10 @@ ip_vs_add_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest) 


	ip_vs_addr_copy(svc->af, &daddr, &udest->addr);



	/*

	 * Check if the dest already exists in the list

	 */

	/* We use function that requires RCU lock */

	rcu_read_lock();

	dest = ip_vs_lookup_dest(svc, &daddr, dport);

	rcu_read_unlock();



	if (dest != NULL) {

		IP_VS_DBG(1, "%s(): dest already exists\n", __func__);
@@ -997,10 +996,10 @@ ip_vs_edit_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest) 


	ip_vs_addr_copy(svc->af, &daddr, &udest->addr);



	/*

	 *  Lookup the destination list

	 */

	/* We use function that requires RCU lock */

	rcu_read_lock();

	dest = ip_vs_lookup_dest(svc, &daddr, dport);

	rcu_read_unlock();



	if (dest == NULL) {

		IP_VS_DBG(1, "%s(): dest doesn't exist\n", __func__);
@@ -1069,7 +1068,7 @@ static void __ip_vs_unlink_dest(struct ip_vs_service *svc, 
	/*

	 *  Remove it from the d-linked destination list.

	 */

	list_del(&dest->n_list);

	list_del_rcu(&dest->n_list);

	svc->num_dests--;



	if (svcupd && svc->scheduler->del_dest)
@@ -1094,7 +1093,10 @@ ip_vs_del_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest) 


	EnterFunction(2);



	/* We use function that requires RCU lock */

	rcu_read_lock();

	dest = ip_vs_lookup_dest(svc, &udest->addr, dport);

	rcu_read_unlock();



	if (dest == NULL) {

		IP_VS_DBG(1, "%s(): destination not found!\n", __func__);
@@ -2104,7 +2106,7 @@ static int ip_vs_info_seq_show(struct seq_file *seq, void *v) 
		else

			seq_putc(seq, '\n');



		list_for_each_entry(dest, &svc->destinations, n_list) {

		list_for_each_entry_rcu(dest, &svc->destinations, n_list) {

#ifdef CONFIG_IP_VS_IPV6

			if (dest->af == AF_INET6)

				seq_printf(seq,

net/netfilter/ipvs/ip_vs_sync.c

+4 −7
Original line number Diff line number Diff line
@@ -858,23 +858,20 @@ static void ip_vs_proc_conn(struct net *net, struct ip_vs_conn_param *param, 
		flags |= cp->flags & ~IP_VS_CONN_F_BACKUP_UPD_MASK;

		cp->flags = flags;

		spin_unlock(&cp->lock);

		if (!dest) {

			dest = ip_vs_try_bind_dest(cp);

			if (dest)

				ip_vs_dest_put(dest);

		}

		if (!dest)

			ip_vs_try_bind_dest(cp);

	} else {

		/*

		 * Find the appropriate destination for the connection.

		 * If it is not found the connection will remain unbound

		 * but still handled.

		 */

		rcu_read_lock();

		dest = ip_vs_find_dest(net, type, daddr, dport, param->vaddr,

				       param->vport, protocol, fwmark, flags);



		cp = ip_vs_conn_new(param, daddr, dport, flags, dest, fwmark);

		if (dest)

			ip_vs_dest_put(dest);

		rcu_read_unlock();

		if (!cp) {

			if (param->pe_data)

				kfree(param->pe_data);