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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: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2009-10-23 17:51:26 +00:00 committed by David S. Miller
parent b37b62fea1
commit ef9a9d1183
2 changed files with 51 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/net/ipip.h
View File

@ -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 { \

73
net/ipv6/sit.c
View File

@ -240,15 +240,22 @@ failed:
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)