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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
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@ -88,8 +88,10 @@ struct ip6_tnl_net {
struct ip6_tnl **tnls[2]; 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) 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 * else %NULL
**/ **/
#define for_each_ip6_tunnel_rcu(start) \
for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
static struct ip6_tnl * static struct ip6_tnl *
ip6_tnl_lookup(struct net *net, struct in6_addr *remote, struct in6_addr *local) 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 *t;
struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id); 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) && if (ipv6_addr_equal(local, &t->parms.laddr) &&
ipv6_addr_equal(remote, &t->parms.raddr) && ipv6_addr_equal(remote, &t->parms.raddr) &&
(t->dev->flags & IFF_UP)) (t->dev->flags & IFF_UP))
return t; 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 t;
return NULL; 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); struct ip6_tnl **tp = ip6_tnl_bucket(ip6n, &t->parms);
spin_lock_bh(&ip6_tnl_lock);
t->next = *tp; t->next = *tp;
write_lock_bh(&ip6_tnl_lock); rcu_assign_pointer(*tp, t);
*tp = t; spin_unlock_bh(&ip6_tnl_lock);
write_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) { for (tp = ip6_tnl_bucket(ip6n, &t->parms); *tp; tp = &(*tp)->next) {
if (t == *tp) { if (t == *tp) {
write_lock_bh(&ip6_tnl_lock); spin_lock_bh(&ip6_tnl_lock);
*tp = t->next; *tp = t->next;
write_unlock_bh(&ip6_tnl_lock); spin_unlock_bh(&ip6_tnl_lock);
break; 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); struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
if (dev == ip6n->fb_tnl_dev) { if (dev == ip6n->fb_tnl_dev) {
write_lock_bh(&ip6_tnl_lock); spin_lock_bh(&ip6_tnl_lock);
ip6n->tnls_wc[0] = NULL; ip6n->tnls_wc[0] = NULL;
write_unlock_bh(&ip6_tnl_lock); spin_unlock_bh(&ip6_tnl_lock);
} else { } else {
ip6_tnl_unlink(ip6n, t); 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 in trouble since we might need the source address for further
processing of the error. */ processing of the error. */
read_lock(&ip6_tnl_lock); rcu_read_lock();
if ((t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->daddr, if ((t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->daddr,
&ipv6h->saddr)) == NULL) &ipv6h->saddr)) == NULL)
goto out; goto out;
@ -482,7 +488,7 @@ ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt,
*msg = rel_msg; *msg = rel_msg;
out: out:
read_unlock(&ip6_tnl_lock); rcu_read_unlock();
return err; return err;
} }
@ -693,23 +699,23 @@ static int ip6_tnl_rcv(struct sk_buff *skb, __u16 protocol,
struct ip6_tnl *t; struct ip6_tnl *t;
struct ipv6hdr *ipv6h = ipv6_hdr(skb); 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, if ((t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->saddr,
&ipv6h->daddr)) != NULL) { &ipv6h->daddr)) != NULL) {
if (t->parms.proto != ipproto && t->parms.proto != 0) { if (t->parms.proto != ipproto && t->parms.proto != 0) {
read_unlock(&ip6_tnl_lock); rcu_read_unlock();
goto discard; goto discard;
} }
if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
read_unlock(&ip6_tnl_lock); rcu_read_unlock();
goto discard; goto discard;
} }
if (!ip6_tnl_rcv_ctl(t)) { if (!ip6_tnl_rcv_ctl(t)) {
t->dev->stats.rx_dropped++; t->dev->stats.rx_dropped++;
read_unlock(&ip6_tnl_lock); rcu_read_unlock();
goto discard; goto discard;
} }
secpath_reset(skb); 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_packets++;
t->dev->stats.rx_bytes += skb->len; t->dev->stats.rx_bytes += skb->len;
netif_rx(skb); netif_rx(skb);
read_unlock(&ip6_tnl_lock); rcu_read_unlock();
return 0; return 0;
} }
read_unlock(&ip6_tnl_lock); rcu_read_unlock();
return 1; return 1;
discard: discard: