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authorEric Dumazet <eric.dumazet@gmail.com>2010-09-15 11:35:10 +0000
committerDavid S. Miller <davem@davemloft.net>2010-09-15 19:29:47 -0700
commit3a43be3c328ff42327da0b141de360dc4587aab7 (patch)
tree669c86867533e70dfe3a2aa52e17802aeb2e60bf /net/ipv6/sit.c
parent1507850b400492fdedc3064d3b8db5e9a1c871e3 (diff)
downloadop-kernel-dev-3a43be3c328ff42327da0b141de360dc4587aab7.zip
op-kernel-dev-3a43be3c328ff42327da0b141de360dc4587aab7.tar.gz
sit: get rid of ipip6_lock
As RTNL is held while doing tunnels inserts and deletes, we can remove ipip6_lock spinlock. My initial RCU conversion was conservative and converted the rwlock to spinlock, with no RTNL requirement. Use appropriate rcu annotations and modern lockdep checks as well. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/sit.c')
-rw-r--r--net/ipv6/sit.c64
1 files changed, 31 insertions, 33 deletions
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 86618eb..6822481 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -68,19 +68,18 @@ static void ipip6_tunnel_setup(struct net_device *dev);
static int sit_net_id __read_mostly;
struct sit_net {
- struct ip_tunnel *tunnels_r_l[HASH_SIZE];
- struct ip_tunnel *tunnels_r[HASH_SIZE];
- struct ip_tunnel *tunnels_l[HASH_SIZE];
- struct ip_tunnel *tunnels_wc[1];
- struct ip_tunnel **tunnels[4];
+ struct ip_tunnel __rcu *tunnels_r_l[HASH_SIZE];
+ struct ip_tunnel __rcu *tunnels_r[HASH_SIZE];
+ struct ip_tunnel __rcu *tunnels_l[HASH_SIZE];
+ struct ip_tunnel __rcu *tunnels_wc[1];
+ struct ip_tunnel __rcu **tunnels[4];
struct net_device *fb_tunnel_dev;
};
/*
- * Locking : hash tables are protected by RCU and a spinlock
+ * Locking : hash tables are protected by RCU and RTNL
*/
-static DEFINE_SPINLOCK(ipip6_lock);
#define for_each_ip_tunnel_rcu(start) \
for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
@@ -91,8 +90,8 @@ static DEFINE_SPINLOCK(ipip6_lock);
static struct ip_tunnel * ipip6_tunnel_lookup(struct net *net,
struct net_device *dev, __be32 remote, __be32 local)
{
- unsigned h0 = HASH(remote);
- unsigned h1 = HASH(local);
+ unsigned int h0 = HASH(remote);
+ unsigned int h1 = HASH(local);
struct ip_tunnel *t;
struct sit_net *sitn = net_generic(net, sit_net_id);
@@ -121,12 +120,12 @@ static struct ip_tunnel * ipip6_tunnel_lookup(struct net *net,
return NULL;
}
-static struct ip_tunnel **__ipip6_bucket(struct sit_net *sitn,
+static struct ip_tunnel __rcu **__ipip6_bucket(struct sit_net *sitn,
struct ip_tunnel_parm *parms)
{
__be32 remote = parms->iph.daddr;
__be32 local = parms->iph.saddr;
- unsigned h = 0;
+ unsigned int h = 0;
int prio = 0;
if (remote) {
@@ -140,7 +139,7 @@ static struct ip_tunnel **__ipip6_bucket(struct sit_net *sitn,
return &sitn->tunnels[prio][h];
}
-static inline struct ip_tunnel **ipip6_bucket(struct sit_net *sitn,
+static inline struct ip_tunnel __rcu **ipip6_bucket(struct sit_net *sitn,
struct ip_tunnel *t)
{
return __ipip6_bucket(sitn, &t->parms);
@@ -148,13 +147,14 @@ static inline struct ip_tunnel **ipip6_bucket(struct sit_net *sitn,
static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
{
- struct ip_tunnel **tp;
-
- for (tp = ipip6_bucket(sitn, t); *tp; tp = &(*tp)->next) {
- if (t == *tp) {
- spin_lock_bh(&ipip6_lock);
- *tp = t->next;
- spin_unlock_bh(&ipip6_lock);
+ struct ip_tunnel __rcu **tp;
+ struct ip_tunnel *iter;
+
+ for (tp = ipip6_bucket(sitn, t);
+ (iter = rtnl_dereference(*tp)) != NULL;
+ tp = &iter->next) {
+ if (t == iter) {
+ rcu_assign_pointer(*tp, t->next);
break;
}
}
@@ -162,12 +162,10 @@ static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
{
- struct ip_tunnel **tp = ipip6_bucket(sitn, t);
+ struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);
- spin_lock_bh(&ipip6_lock);
- t->next = *tp;
+ rcu_assign_pointer(t->next, rtnl_dereference(*tp));
rcu_assign_pointer(*tp, t);
- spin_unlock_bh(&ipip6_lock);
}
static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
@@ -187,17 +185,20 @@ static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
#endif
}
-static struct ip_tunnel * ipip6_tunnel_locate(struct net *net,
+static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
struct ip_tunnel_parm *parms, int create)
{
__be32 remote = parms->iph.daddr;
__be32 local = parms->iph.saddr;
- struct ip_tunnel *t, **tp, *nt;
+ struct ip_tunnel *t, *nt;
+ struct ip_tunnel __rcu **tp;
struct net_device *dev;
char name[IFNAMSIZ];
struct sit_net *sitn = net_generic(net, sit_net_id);
- for (tp = __ipip6_bucket(sitn, parms); (t = *tp) != NULL; tp = &t->next) {
+ for (tp = __ipip6_bucket(sitn, parms);
+ (t = rtnl_dereference(*tp)) != NULL;
+ tp = &t->next) {
if (local == t->parms.iph.saddr &&
remote == t->parms.iph.daddr &&
parms->link == t->parms.link) {
@@ -340,7 +341,7 @@ ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
ASSERT_RTNL();
- for (p = t->prl; p; p = p->next) {
+ for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
if (p->addr == a->addr) {
if (chg) {
p->flags = a->flags;
@@ -451,15 +452,12 @@ 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) {
- spin_lock_bh(&ipip6_lock);
- sitn->tunnels_wc[0] = NULL;
- spin_unlock_bh(&ipip6_lock);
- dev_put(dev);
+ rcu_assign_pointer(sitn->tunnels_wc[0], NULL);
} else {
ipip6_tunnel_unlink(sitn, netdev_priv(dev));
ipip6_tunnel_del_prl(netdev_priv(dev), NULL);
- dev_put(dev);
}
+ dev_put(dev);
}
@@ -590,7 +588,7 @@ __be32 try_6rd(struct in6_addr *v6dst, struct ip_tunnel *tunnel)
#ifdef CONFIG_IPV6_SIT_6RD
if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
tunnel->ip6rd.prefixlen)) {
- unsigned pbw0, pbi0;
+ unsigned int pbw0, pbi0;
int pbi1;
u32 d;
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