From 94767632623c7bf5b16a0cf963ec93a8ad9acca4 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 15 Sep 2010 20:25:34 +0000 Subject: ip6tnl: get rid of ip6_tnl_lock As RTNL is held while doing tunnels inserts and deletes, we can remove ip6_tnl_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 Signed-off-by: David S. Miller --- net/ipv6/ip6_tunnel.c | 58 +++++++++++++++++++++++++-------------------------- 1 file changed, 28 insertions(+), 30 deletions(-) (limited to 'net/ipv6') diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c index 29f99dd75bc6..9289cecac4de 100644 --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -83,15 +83,14 @@ struct ip6_tnl_net { /* the IPv6 tunnel fallback device */ struct net_device *fb_tnl_dev; /* lists for storing tunnels in use */ - struct ip6_tnl *tnls_r_l[HASH_SIZE]; - struct ip6_tnl *tnls_wc[1]; - struct ip6_tnl **tnls[2]; + struct ip6_tnl __rcu *tnls_r_l[HASH_SIZE]; + struct ip6_tnl __rcu *tnls_wc[1]; + struct ip6_tnl __rcu **tnls[2]; }; /* - * Locking : hash tables are protected by RCU and a spinlock + * Locking : hash tables are protected by RCU and RTNL */ -static DEFINE_SPINLOCK(ip6_tnl_lock); static inline struct dst_entry *ip6_tnl_dst_check(struct ip6_tnl *t) { @@ -138,8 +137,8 @@ static inline void ip6_tnl_dst_store(struct ip6_tnl *t, struct dst_entry *dst) static struct ip6_tnl * ip6_tnl_lookup(struct net *net, struct in6_addr *remote, struct in6_addr *local) { - unsigned h0 = HASH(remote); - unsigned h1 = HASH(local); + unsigned int h0 = HASH(remote); + unsigned int h1 = HASH(local); struct ip6_tnl *t; struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id); @@ -167,7 +166,7 @@ ip6_tnl_lookup(struct net *net, struct in6_addr *remote, struct in6_addr *local) * Return: head of IPv6 tunnel list **/ -static struct ip6_tnl ** +static struct ip6_tnl __rcu ** ip6_tnl_bucket(struct ip6_tnl_net *ip6n, struct ip6_tnl_parm *p) { struct in6_addr *remote = &p->raddr; @@ -190,12 +189,10 @@ ip6_tnl_bucket(struct ip6_tnl_net *ip6n, struct ip6_tnl_parm *p) static void 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 __rcu **tp = ip6_tnl_bucket(ip6n, &t->parms); - spin_lock_bh(&ip6_tnl_lock); - t->next = *tp; + rcu_assign_pointer(t->next , rtnl_dereference(*tp)); rcu_assign_pointer(*tp, t); - spin_unlock_bh(&ip6_tnl_lock); } /** @@ -206,13 +203,14 @@ ip6_tnl_link(struct ip6_tnl_net *ip6n, struct ip6_tnl *t) static void ip6_tnl_unlink(struct ip6_tnl_net *ip6n, struct ip6_tnl *t) { - struct ip6_tnl **tp; - - for (tp = ip6_tnl_bucket(ip6n, &t->parms); *tp; tp = &(*tp)->next) { - if (t == *tp) { - spin_lock_bh(&ip6_tnl_lock); - *tp = t->next; - spin_unlock_bh(&ip6_tnl_lock); + struct ip6_tnl __rcu **tp; + struct ip6_tnl *iter; + + for (tp = ip6_tnl_bucket(ip6n, &t->parms); + (iter = rtnl_dereference(*tp)) != NULL; + tp = &iter->next) { + if (t == iter) { + rcu_assign_pointer(*tp, t->next); break; } } @@ -290,10 +288,13 @@ static struct ip6_tnl *ip6_tnl_locate(struct net *net, { struct in6_addr *remote = &p->raddr; struct in6_addr *local = &p->laddr; + struct ip6_tnl __rcu **tp; struct ip6_tnl *t; struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id); - for (t = *ip6_tnl_bucket(ip6n, p); t; t = t->next) { + for (tp = ip6_tnl_bucket(ip6n, p); + (t = rtnl_dereference(*tp)) != NULL; + tp = &t->next) { if (ipv6_addr_equal(local, &t->parms.laddr) && ipv6_addr_equal(remote, &t->parms.raddr)) return t; @@ -318,13 +319,10 @@ ip6_tnl_dev_uninit(struct net_device *dev) struct net *net = dev_net(dev); struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id); - if (dev == ip6n->fb_tnl_dev) { - spin_lock_bh(&ip6_tnl_lock); - ip6n->tnls_wc[0] = NULL; - spin_unlock_bh(&ip6_tnl_lock); - } else { + if (dev == ip6n->fb_tnl_dev) + rcu_assign_pointer(ip6n->tnls_wc[0], NULL); + else ip6_tnl_unlink(ip6n, t); - } ip6_tnl_dst_reset(t); dev_put(dev); } @@ -1369,7 +1367,7 @@ static void __net_init ip6_fb_tnl_dev_init(struct net_device *dev) ip6_tnl_dev_init_gen(dev); t->parms.proto = IPPROTO_IPV6; dev_hold(dev); - ip6n->tnls_wc[0] = t; + rcu_assign_pointer(ip6n->tnls_wc[0], t); } static struct xfrm6_tunnel ip4ip6_handler __read_mostly = { @@ -1391,14 +1389,14 @@ static void __net_exit ip6_tnl_destroy_tunnels(struct ip6_tnl_net *ip6n) LIST_HEAD(list); for (h = 0; h < HASH_SIZE; h++) { - t = ip6n->tnls_r_l[h]; + t = rtnl_dereference(ip6n->tnls_r_l[h]); while (t != NULL) { unregister_netdevice_queue(t->dev, &list); - t = t->next; + t = rtnl_dereference(t->next); } } - t = ip6n->tnls_wc[0]; + t = rtnl_dereference(ip6n->tnls_wc[0]); unregister_netdevice_queue(t->dev, &list); unregister_netdevice_many(&list); } -- cgit v1.2.3-59-g8ed1b