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ipv6 sit: RCU conversion phase II

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SIT tunnels use one rwlock to protect their hash tables.

This locking scheme can be converted to RCU for free, since netdevice
already must wait for a RCU grace period at dismantle time.

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 17:52:14 +00:00 committed by David S. Miller
parent ef9a9d1183
commit 4543c10de2
1 changed files with 27 additions and 18 deletions
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45
net/ipv6/sit.c
View file

@ -77,8 +77,17 @@ struct sit_net {
struct net_device *fb_tunnel_dev;
};
static DEFINE_RWLOCK(ipip6_lock);
/*
* Locking : hash tables are protected by RCU and a spinlock
*/
static DEFINE_SPINLOCK(ipip6_lock);
#define for_each_ip_tunnel_rcu(start) \
for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
/*
* Must be invoked with rcu_read_lock
*/
static struct ip_tunnel * ipip6_tunnel_lookup(struct net *net,
struct net_device *dev, __be32 remote, __be32 local)
{
@ -87,26 +96,26 @@ static struct ip_tunnel * ipip6_tunnel_lookup(struct net *net,
struct ip_tunnel *t;
struct sit_net *sitn = net_generic(net, sit_net_id);
for (t = sitn->tunnels_r_l[h0^h1]; t; t = t->next) {
for_each_ip_tunnel_rcu(sitn->tunnels_r_l[h0 ^ h1]) {
if (local == t->parms.iph.saddr &&
remote == t->parms.iph.daddr &&
(!dev || !t->parms.link || dev->iflink == t->parms.link) &&
(t->dev->flags & IFF_UP))
return t;
}
for (t = sitn->tunnels_r[h0]; t; t = t->next) {
for_each_ip_tunnel_rcu(sitn->tunnels_r[h0]) {
if (remote == t->parms.iph.daddr &&
(!dev || !t->parms.link || dev->iflink == t->parms.link) &&
(t->dev->flags & IFF_UP))
return t;
}
for (t = sitn->tunnels_l[h1]; t; t = t->next) {
for_each_ip_tunnel_rcu(sitn->tunnels_l[h1]) {
if (local == t->parms.iph.saddr &&
(!dev || !t->parms.link || dev->iflink == t->parms.link) &&
(t->dev->flags & IFF_UP))
return t;
}
t = sitn->tunnels_wc[0];
t = rcu_dereference(sitn->tunnels_wc[0]);
if ((t != NULL) && (t->dev->flags & IFF_UP))
return t;
return NULL;
@ -143,9 +152,9 @@ static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
for (tp = ipip6_bucket(sitn, t); *tp; tp = &(*tp)->next) {
if (t == *tp) {
write_lock_bh(&ipip6_lock);
spin_lock_bh(&ipip6_lock);
*tp = t->next;
write_unlock_bh(&ipip6_lock);
spin_unlock_bh(&ipip6_lock);
break;
}
}
@ -155,10 +164,10 @@ static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
{
struct ip_tunnel **tp = ipip6_bucket(sitn, t);
spin_lock_bh(&ipip6_lock);
t->next = *tp;
write_lock_bh(&ipip6_lock);
*tp = t;
write_unlock_bh(&ipip6_lock);
rcu_assign_pointer(*tp, t);
spin_unlock_bh(&ipip6_lock);
}
static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
@ -447,9 +456,9 @@ static void ipip6_tunnel_uninit(struct net_device *dev)
struct sit_net *sitn = net_generic(net, sit_net_id);
if (dev == sitn->fb_tunnel_dev) {
write_lock_bh(&ipip6_lock);
spin_lock_bh(&ipip6_lock);
sitn->tunnels_wc[0] = NULL;
write_unlock_bh(&ipip6_lock);
spin_unlock_bh(&ipip6_lock);
dev_put(dev);
} else {
ipip6_tunnel_unlink(sitn, netdev_priv(dev));
@ -502,7 +511,7 @@ static int ipip6_err(struct sk_buff *skb, u32 info)
err = -ENOENT;
read_lock(&ipip6_lock);
rcu_read_lock();
t = ipip6_tunnel_lookup(dev_net(skb->dev),
skb->dev,
iph->daddr,
@ -520,7 +529,7 @@ static int ipip6_err(struct sk_buff *skb, u32 info)
t->err_count = 1;
t->err_time = jiffies;
out:
read_unlock(&ipip6_lock);
rcu_read_unlock();
return err;
}
@ -540,7 +549,7 @@ static int ipip6_rcv(struct sk_buff *skb)
iph = ip_hdr(skb);
read_lock(&ipip6_lock);
rcu_read_lock();
tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
iph->saddr, iph->daddr);
if (tunnel != NULL) {
@ -554,7 +563,7 @@ static int ipip6_rcv(struct sk_buff *skb)
if ((tunnel->dev->priv_flags & IFF_ISATAP) &&
!isatap_chksrc(skb, iph, tunnel)) {
tunnel->dev->stats.rx_errors++;
read_unlock(&ipip6_lock);
rcu_read_unlock();
kfree_skb(skb);
return 0;
}
@ -565,12 +574,12 @@ static int ipip6_rcv(struct sk_buff *skb)
nf_reset(skb);
ipip6_ecn_decapsulate(iph, skb);
netif_rx(skb);
read_unlock(&ipip6_lock);
rcu_read_unlock();
return 0;
}
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
read_unlock(&ipip6_lock);
rcu_read_unlock();
out:
kfree_skb(skb);
return 0;