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ipip: convert hash tables locking to RCU

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IPIP 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 05:42:02 +00:00 committed by David S. Miller
parent 91cc3bb0b0
commit 8f95dd63a2
1 changed files with 28 additions and 21 deletions
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49
net/ipv4/ipip.c
View file

@ -134,7 +134,13 @@ static void ipip_fb_tunnel_init(struct net_device *dev);
static void ipip_tunnel_init(struct net_device *dev);
static void ipip_tunnel_setup(struct net_device *dev);
static DEFINE_RWLOCK(ipip_lock);
/*
* Locking : hash tables are protected by RCU and a spinlock
*/
static DEFINE_SPINLOCK(ipip_lock);
#define for_each_ip_tunnel_rcu(start) \
for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
static struct ip_tunnel * ipip_tunnel_lookup(struct net *net,
__be32 remote, __be32 local)
@ -144,20 +150,21 @@ static struct ip_tunnel * ipip_tunnel_lookup(struct net *net,
struct ip_tunnel *t;
struct ipip_net *ipn = net_generic(net, ipip_net_id);
for (t = ipn->tunnels_r_l[h0^h1]; t; t = t->next) {
for_each_ip_tunnel_rcu(ipn->tunnels_r_l[h0 ^ h1])
if (local == t->parms.iph.saddr &&
remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
return t;
}
for (t = ipn->tunnels_r[h0]; t; t = t->next) {
for_each_ip_tunnel_rcu(ipn->tunnels_r[h0])
if (remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
return t;
}
for (t = ipn->tunnels_l[h1]; t; t = t->next) {
for_each_ip_tunnel_rcu(ipn->tunnels_l[h1])
if (local == t->parms.iph.saddr && (t->dev->flags&IFF_UP))
return t;
}
if ((t = ipn->tunnels_wc[0]) != NULL && (t->dev->flags&IFF_UP))
t = rcu_dereference(ipn->tunnels_wc[0]);
if (t && (t->dev->flags&IFF_UP))
return t;
return NULL;
}
@ -193,9 +200,9 @@ static void ipip_tunnel_unlink(struct ipip_net *ipn, struct ip_tunnel *t)
for (tp = ipip_bucket(ipn, t); *tp; tp = &(*tp)->next) {
if (t == *tp) {
write_lock_bh(&ipip_lock);
spin_lock_bh(&ipip_lock);
*tp = t->next;
write_unlock_bh(&ipip_lock);
spin_unlock_bh(&ipip_lock);
break;
}
}
@ -205,10 +212,10 @@ static void ipip_tunnel_link(struct ipip_net *ipn, struct ip_tunnel *t)
{
struct ip_tunnel **tp = ipip_bucket(ipn, t);
spin_lock_bh(&ipip_lock);
t->next = *tp;
write_lock_bh(&ipip_lock);
*tp = t;
write_unlock_bh(&ipip_lock);
rcu_assign_pointer(*tp, t);
spin_unlock_bh(&ipip_lock);
}
static struct ip_tunnel * ipip_tunnel_locate(struct net *net,
@ -267,9 +274,9 @@ static void ipip_tunnel_uninit(struct net_device *dev)
struct ipip_net *ipn = net_generic(net, ipip_net_id);
if (dev == ipn->fb_tunnel_dev) {
write_lock_bh(&ipip_lock);
spin_lock_bh(&ipip_lock);
ipn->tunnels_wc[0] = NULL;
write_unlock_bh(&ipip_lock);
spin_unlock_bh(&ipip_lock);
} else
ipip_tunnel_unlink(ipn, netdev_priv(dev));
dev_put(dev);
@ -318,7 +325,7 @@ static int ipip_err(struct sk_buff *skb, u32 info)
err = -ENOENT;
read_lock(&ipip_lock);
rcu_read_lock();
t = ipip_tunnel_lookup(dev_net(skb->dev), iph->daddr, iph->saddr);
if (t == NULL || t->parms.iph.daddr == 0)
goto out;
@ -333,7 +340,7 @@ static int ipip_err(struct sk_buff *skb, u32 info)
t->err_count = 1;
t->err_time = jiffies;
out:
read_unlock(&ipip_lock);
rcu_read_unlock();
return err;
}
@ -351,11 +358,11 @@ static int ipip_rcv(struct sk_buff *skb)
struct ip_tunnel *tunnel;
const struct iphdr *iph = ip_hdr(skb);
read_lock(&ipip_lock);
rcu_read_lock();
if ((tunnel = ipip_tunnel_lookup(dev_net(skb->dev),
iph->saddr, iph->daddr)) != NULL) {
if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
read_unlock(&ipip_lock);
rcu_read_unlock();
kfree_skb(skb);
return 0;
}
@ -374,10 +381,10 @@ static int ipip_rcv(struct sk_buff *skb)
nf_reset(skb);
ipip_ecn_decapsulate(iph, skb);
netif_rx(skb);
read_unlock(&ipip_lock);
rcu_read_unlock();
return 0;
}
read_unlock(&ipip_lock);
rcu_read_unlock();
return -1;
}