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Commit ef9a9d11 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ipv6 sit: RCU conversion phase I 



SIT tunnels use one rwlock to protect their prl entries.

This first patch adds RCU locking for prl management,
with standard call_rcu() calls.

Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b37b62fe

include/net/ipip.h

+1 −0
Original line number Diff line number Diff line
@@ -45,6 +45,7 @@ struct ip_tunnel_prl_entry 
	struct ip_tunnel_prl_entry	*next;

	__be32				addr;

	u16				flags;

	struct rcu_head			rcu_head;

};



#define IPTUNNEL_XMIT() do {						\

net/ipv6/sit.c

+50 −23
Original line number Diff line number Diff line
@@ -240,15 +240,22 @@ static struct ip_tunnel * ipip6_tunnel_locate(struct net *net, 
	return NULL;

}



static DEFINE_SPINLOCK(ipip6_prl_lock);



#define for_each_prl_rcu(start)			\

	for (prl = rcu_dereference(start);	\

	     prl;				\

	     prl = rcu_dereference(prl->next))



static struct ip_tunnel_prl_entry *

__ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)

{

	struct ip_tunnel_prl_entry *p = (struct ip_tunnel_prl_entry *)NULL;

	struct ip_tunnel_prl_entry *prl;



	for (p = t->prl; p; p = p->next)

		if (p->addr == addr)

	for_each_prl_rcu(t->prl)

		if (prl->addr == addr)

			break;

	return p;

	return prl;



}
@@ -273,7 +280,7 @@ static int ipip6_tunnel_get_prl(struct ip_tunnel *t, 
		kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :

		NULL;



	read_lock(&ipip6_lock);

	rcu_read_lock();



	ca = t->prl_count < cmax ? t->prl_count : cmax;
@@ -291,7 +298,7 @@ static int ipip6_tunnel_get_prl(struct ip_tunnel *t, 
	}



	c = 0;

	for (prl = t->prl; prl; prl = prl->next) {

	for_each_prl_rcu(t->prl) {

		if (c >= cmax)

			break;

		if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
@@ -303,7 +310,7 @@ static int ipip6_tunnel_get_prl(struct ip_tunnel *t, 
			break;

	}

out:

	read_unlock(&ipip6_lock);

	rcu_read_unlock();



	len = sizeof(*kp) * c;

	ret = 0;
@@ -324,12 +331,14 @@ ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg) 
	if (a->addr == htonl(INADDR_ANY))

		return -EINVAL;



	write_lock(&ipip6_lock);

	spin_lock(&ipip6_prl_lock);



	for (p = t->prl; p; p = p->next) {

		if (p->addr == a->addr) {

			if (chg)

				goto update;

			if (chg) {

				p->flags = a->flags;

				goto out;

			}

			err = -EEXIST;

			goto out;

		}
@@ -346,46 +355,63 @@ ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg) 
		goto out;

	}



	INIT_RCU_HEAD(&p->rcu_head);

	p->next = t->prl;

	t->prl = p;

	t->prl_count++;

update:

	p->addr = a->addr;

	p->flags = a->flags;

	t->prl_count++;

	rcu_assign_pointer(t->prl, p);

out:

	write_unlock(&ipip6_lock);

	spin_unlock(&ipip6_prl_lock);

	return err;

}



static void prl_entry_destroy_rcu(struct rcu_head *head)

{

	kfree(container_of(head, struct ip_tunnel_prl_entry, rcu_head));

}



static void prl_list_destroy_rcu(struct rcu_head *head)

{

	struct ip_tunnel_prl_entry *p, *n;



	p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);

	do {

		n = p->next;

		kfree(p);

		p = n;

	} while (p);

}



static int

ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)

{

	struct ip_tunnel_prl_entry *x, **p;

	int err = 0;



	write_lock(&ipip6_lock);

	spin_lock(&ipip6_prl_lock);



	if (a && a->addr != htonl(INADDR_ANY)) {

		for (p = &t->prl; *p; p = &(*p)->next) {

			if ((*p)->addr == a->addr) {

				x = *p;

				*p = x->next;

				kfree(x);

				call_rcu(&x->rcu_head, prl_entry_destroy_rcu);

				t->prl_count--;

				goto out;

			}

		}

		err = -ENXIO;

	} else {

		while (t->prl) {

		if (t->prl) {

			t->prl_count = 0;

			x = t->prl;

			t->prl = t->prl->next;

			kfree(x);

			t->prl_count--;

			call_rcu(&x->rcu_head, prl_list_destroy_rcu);

			t->prl = NULL;

		}

	}

out:

	write_unlock(&ipip6_lock);

	spin_unlock(&ipip6_prl_lock);

	return err;

}
@@ -395,7 +421,7 @@ isatap_chksrc(struct sk_buff *skb, struct iphdr *iph, struct ip_tunnel *t) 
	struct ip_tunnel_prl_entry *p;

	int ok = 1;



	read_lock(&ipip6_lock);

	rcu_read_lock();

	p = __ipip6_tunnel_locate_prl(t, iph->saddr);

	if (p) {

		if (p->flags & PRL_DEFAULT)
@@ -411,7 +437,7 @@ isatap_chksrc(struct sk_buff *skb, struct iphdr *iph, struct ip_tunnel *t) 
		else

			ok = 0;

	}

	read_unlock(&ipip6_lock);

	rcu_read_unlock();

	return ok;

}
@@ -1192,6 +1218,7 @@ static void __exit sit_cleanup(void) 
	xfrm4_tunnel_deregister(&sit_handler, AF_INET6);



	unregister_pernet_gen_device(sit_net_id, &sit_net_ops);

	rcu_barrier(); /* Wait for completion of call_rcu()'s */

}



static int __init sit_init(void)