iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

ipv6 sit: RCU conversion phase II

Browse Source 
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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

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;