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OpenCloudOS-Kernel
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ip6tnl: convert hash tables locking to RCU 

ip6_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 06:34:34 +00:00 committed by David S. Miller
parent 8f95dd63a2
commit 2922bc8aed
1 changed files with 25 additions and 19 deletions
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44
net/ipv6/ip6_tunnel.c
View File

@ -88,8 +88,10 @@ struct ip6_tnl_net {
struct ip6_tnl **tnls[2];
};
/* lock for the tunnel lists */
static DEFINE_RWLOCK(ip6_tnl_lock);
/*
* Locking : hash tables are protected by RCU and a spinlock
*/
static DEFINE_SPINLOCK(ip6_tnl_lock);
static inline struct dst_entry *ip6_tnl_dst_check(struct ip6_tnl *t)
{
@ -130,6 +132,9 @@ static inline void ip6_tnl_dst_store(struct ip6_tnl *t, struct dst_entry *dst)
* else %NULL
**/
#define for_each_ip6_tunnel_rcu(start) \
for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
static struct ip6_tnl *
ip6_tnl_lookup(struct net *net, struct in6_addr *remote, struct in6_addr *local)
{
@ -138,13 +143,14 @@ ip6_tnl_lookup(struct net *net, struct in6_addr *remote, struct in6_addr *local)
struct ip6_tnl *t;
struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
for (t = ip6n->tnls_r_l[h0 ^ h1]; t; t = t->next) {
for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[h0 ^ h1]) {
if (ipv6_addr_equal(local, &t->parms.laddr) &&
ipv6_addr_equal(remote, &t->parms.raddr) &&
(t->dev->flags & IFF_UP))
return t;
}
if ((t = ip6n->tnls_wc[0]) != NULL && (t->dev->flags & IFF_UP))
t = rcu_dereference(ip6n->tnls_wc[0]);
if (t && (t->dev->flags & IFF_UP))
return t;
return NULL;
@ -186,10 +192,10 @@ ip6_tnl_link(struct ip6_tnl_net *ip6n, struct ip6_tnl *t)
{
struct ip6_tnl **tp = ip6_tnl_bucket(ip6n, &t->parms);
spin_lock_bh(&ip6_tnl_lock);
t->next = *tp;
write_lock_bh(&ip6_tnl_lock);
*tp = t;
write_unlock_bh(&ip6_tnl_lock);
rcu_assign_pointer(*tp, t);
spin_unlock_bh(&ip6_tnl_lock);
}
/**
@ -204,9 +210,9 @@ ip6_tnl_unlink(struct ip6_tnl_net *ip6n, struct ip6_tnl *t)
for (tp = ip6_tnl_bucket(ip6n, &t->parms); *tp; tp = &(*tp)->next) {
if (t == *tp) {
write_lock_bh(&ip6_tnl_lock);
spin_lock_bh(&ip6_tnl_lock);
*tp = t->next;
write_unlock_bh(&ip6_tnl_lock);
spin_unlock_bh(&ip6_tnl_lock);
break;
}
}
@ -313,9 +319,9 @@ ip6_tnl_dev_uninit(struct net_device *dev)
struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
if (dev == ip6n->fb_tnl_dev) {
write_lock_bh(&ip6_tnl_lock);
spin_lock_bh(&ip6_tnl_lock);
ip6n->tnls_wc[0] = NULL;
write_unlock_bh(&ip6_tnl_lock);
spin_unlock_bh(&ip6_tnl_lock);
} else {
ip6_tnl_unlink(ip6n, t);
}
@ -409,7 +415,7 @@ ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt,
in trouble since we might need the source address for further
processing of the error. */
read_lock(&ip6_tnl_lock);
rcu_read_lock();
if ((t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->daddr,
&ipv6h->saddr)) == NULL)
goto out;
@ -482,7 +488,7 @@ ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt,
*msg = rel_msg;
out:
read_unlock(&ip6_tnl_lock);
rcu_read_unlock();
return err;
}
@ -693,23 +699,23 @@ static int ip6_tnl_rcv(struct sk_buff *skb, __u16 protocol,
struct ip6_tnl *t;
struct ipv6hdr *ipv6h = ipv6_hdr(skb);
read_lock(&ip6_tnl_lock);
rcu_read_lock();
if ((t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->saddr,
&ipv6h->daddr)) != NULL) {
if (t->parms.proto != ipproto && t->parms.proto != 0) {
read_unlock(&ip6_tnl_lock);
rcu_read_unlock();
goto discard;
}
if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
read_unlock(&ip6_tnl_lock);
rcu_read_unlock();
goto discard;
}
if (!ip6_tnl_rcv_ctl(t)) {
t->dev->stats.rx_dropped++;
read_unlock(&ip6_tnl_lock);
rcu_read_unlock();
goto discard;
}
secpath_reset(skb);
@ -727,10 +733,10 @@ static int ip6_tnl_rcv(struct sk_buff *skb, __u16 protocol,
t->dev->stats.rx_packets++;
t->dev->stats.rx_bytes += skb->len;
netif_rx(skb);
read_unlock(&ip6_tnl_lock);
rcu_read_unlock();
return 0;
}
read_unlock(&ip6_tnl_lock);
rcu_read_unlock();
return 1;
discard: