ipip: get rid of ipip_lock
As RTNL is held while doing tunnels inserts and deletes, we can remove ipip_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>
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@ -122,11 +122,11 @@
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static int ipip_net_id __read_mostly;
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static int ipip_net_id __read_mostly;
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struct ipip_net {
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struct ipip_net {
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struct ip_tunnel *tunnels_r_l[HASH_SIZE];
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struct ip_tunnel __rcu *tunnels_r_l[HASH_SIZE];
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struct ip_tunnel *tunnels_r[HASH_SIZE];
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struct ip_tunnel __rcu *tunnels_r[HASH_SIZE];
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struct ip_tunnel *tunnels_l[HASH_SIZE];
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struct ip_tunnel __rcu *tunnels_l[HASH_SIZE];
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struct ip_tunnel *tunnels_wc[1];
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struct ip_tunnel __rcu *tunnels_wc[1];
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struct ip_tunnel **tunnels[4];
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struct ip_tunnel __rcu **tunnels[4];
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struct net_device *fb_tunnel_dev;
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struct net_device *fb_tunnel_dev;
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};
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};
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@ -135,9 +135,8 @@ static void ipip_tunnel_init(struct net_device *dev);
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static void ipip_tunnel_setup(struct net_device *dev);
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static void ipip_tunnel_setup(struct net_device *dev);
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/*
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/*
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* Locking : hash tables are protected by RCU and a spinlock
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* Locking : hash tables are protected by RCU and RTNL
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*/
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*/
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static DEFINE_SPINLOCK(ipip_lock);
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#define for_each_ip_tunnel_rcu(start) \
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#define for_each_ip_tunnel_rcu(start) \
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for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
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for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
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@ -145,8 +144,8 @@ static DEFINE_SPINLOCK(ipip_lock);
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static struct ip_tunnel * ipip_tunnel_lookup(struct net *net,
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static struct ip_tunnel * ipip_tunnel_lookup(struct net *net,
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__be32 remote, __be32 local)
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__be32 remote, __be32 local)
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{
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{
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unsigned h0 = HASH(remote);
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unsigned int h0 = HASH(remote);
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unsigned h1 = HASH(local);
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unsigned int h1 = HASH(local);
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struct ip_tunnel *t;
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struct ip_tunnel *t;
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struct ipip_net *ipn = net_generic(net, ipip_net_id);
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struct ipip_net *ipn = net_generic(net, ipip_net_id);
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@ -169,12 +168,12 @@ static struct ip_tunnel * ipip_tunnel_lookup(struct net *net,
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return NULL;
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return NULL;
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}
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}
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static struct ip_tunnel **__ipip_bucket(struct ipip_net *ipn,
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static struct ip_tunnel __rcu **__ipip_bucket(struct ipip_net *ipn,
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struct ip_tunnel_parm *parms)
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struct ip_tunnel_parm *parms)
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{
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{
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__be32 remote = parms->iph.daddr;
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__be32 remote = parms->iph.daddr;
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__be32 local = parms->iph.saddr;
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__be32 local = parms->iph.saddr;
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unsigned h = 0;
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unsigned int h = 0;
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int prio = 0;
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int prio = 0;
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if (remote) {
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if (remote) {
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@ -188,7 +187,7 @@ static struct ip_tunnel **__ipip_bucket(struct ipip_net *ipn,
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return &ipn->tunnels[prio][h];
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return &ipn->tunnels[prio][h];
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}
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}
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static inline struct ip_tunnel **ipip_bucket(struct ipip_net *ipn,
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static inline struct ip_tunnel __rcu **ipip_bucket(struct ipip_net *ipn,
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struct ip_tunnel *t)
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struct ip_tunnel *t)
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{
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{
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return __ipip_bucket(ipn, &t->parms);
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return __ipip_bucket(ipn, &t->parms);
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@ -196,13 +195,14 @@ static inline struct ip_tunnel **ipip_bucket(struct ipip_net *ipn,
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static void ipip_tunnel_unlink(struct ipip_net *ipn, struct ip_tunnel *t)
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static void ipip_tunnel_unlink(struct ipip_net *ipn, struct ip_tunnel *t)
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{
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{
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struct ip_tunnel **tp;
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struct ip_tunnel __rcu **tp;
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struct ip_tunnel *iter;
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for (tp = ipip_bucket(ipn, t); *tp; tp = &(*tp)->next) {
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for (tp = ipip_bucket(ipn, t);
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if (t == *tp) {
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(iter = rtnl_dereference(*tp)) != NULL;
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spin_lock_bh(&ipip_lock);
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tp = &iter->next) {
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*tp = t->next;
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if (t == iter) {
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spin_unlock_bh(&ipip_lock);
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rcu_assign_pointer(*tp, t->next);
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break;
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break;
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}
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}
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}
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}
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@ -210,12 +210,10 @@ static void ipip_tunnel_unlink(struct ipip_net *ipn, struct ip_tunnel *t)
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static void ipip_tunnel_link(struct ipip_net *ipn, struct ip_tunnel *t)
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static void ipip_tunnel_link(struct ipip_net *ipn, struct ip_tunnel *t)
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{
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{
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struct ip_tunnel **tp = ipip_bucket(ipn, t);
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struct ip_tunnel __rcu **tp = ipip_bucket(ipn, t);
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spin_lock_bh(&ipip_lock);
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rcu_assign_pointer(t->next, rtnl_dereference(*tp));
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t->next = *tp;
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rcu_assign_pointer(*tp, t);
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rcu_assign_pointer(*tp, t);
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spin_unlock_bh(&ipip_lock);
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}
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}
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static struct ip_tunnel * ipip_tunnel_locate(struct net *net,
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static struct ip_tunnel * ipip_tunnel_locate(struct net *net,
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@ -223,12 +221,15 @@ static struct ip_tunnel * ipip_tunnel_locate(struct net *net,
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{
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{
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__be32 remote = parms->iph.daddr;
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__be32 remote = parms->iph.daddr;
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__be32 local = parms->iph.saddr;
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__be32 local = parms->iph.saddr;
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struct ip_tunnel *t, **tp, *nt;
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struct ip_tunnel *t, *nt;
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struct ip_tunnel __rcu **tp;
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struct net_device *dev;
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struct net_device *dev;
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char name[IFNAMSIZ];
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char name[IFNAMSIZ];
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struct ipip_net *ipn = net_generic(net, ipip_net_id);
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struct ipip_net *ipn = net_generic(net, ipip_net_id);
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for (tp = __ipip_bucket(ipn, parms); (t = *tp) != NULL; tp = &t->next) {
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for (tp = __ipip_bucket(ipn, parms);
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(t = rtnl_dereference(*tp)) != NULL;
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tp = &t->next) {
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if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr)
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if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr)
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return t;
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return t;
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}
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}
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@ -268,16 +269,15 @@ failed_free:
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return NULL;
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return NULL;
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}
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}
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/* called with RTNL */
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static void ipip_tunnel_uninit(struct net_device *dev)
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static void ipip_tunnel_uninit(struct net_device *dev)
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{
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{
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struct net *net = dev_net(dev);
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struct net *net = dev_net(dev);
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struct ipip_net *ipn = net_generic(net, ipip_net_id);
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struct ipip_net *ipn = net_generic(net, ipip_net_id);
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if (dev == ipn->fb_tunnel_dev) {
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if (dev == ipn->fb_tunnel_dev)
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spin_lock_bh(&ipip_lock);
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rcu_assign_pointer(ipn->tunnels_wc[0], NULL);
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ipn->tunnels_wc[0] = NULL;
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else
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spin_unlock_bh(&ipip_lock);
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} else
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ipip_tunnel_unlink(ipn, netdev_priv(dev));
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ipip_tunnel_unlink(ipn, netdev_priv(dev));
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dev_put(dev);
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dev_put(dev);
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}
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}
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@ -741,7 +741,7 @@ static void __net_init ipip_fb_tunnel_init(struct net_device *dev)
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iph->ihl = 5;
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iph->ihl = 5;
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dev_hold(dev);
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dev_hold(dev);
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ipn->tunnels_wc[0] = tunnel;
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rcu_assign_pointer(ipn->tunnels_wc[0], tunnel);
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}
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}
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static struct xfrm_tunnel ipip_handler __read_mostly = {
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static struct xfrm_tunnel ipip_handler __read_mostly = {
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@ -760,11 +760,12 @@ static void ipip_destroy_tunnels(struct ipip_net *ipn, struct list_head *head)
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for (prio = 1; prio < 4; prio++) {
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for (prio = 1; prio < 4; prio++) {
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int h;
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int h;
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for (h = 0; h < HASH_SIZE; h++) {
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for (h = 0; h < HASH_SIZE; h++) {
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struct ip_tunnel *t = ipn->tunnels[prio][h];
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struct ip_tunnel *t;
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t = rtnl_dereference(ipn->tunnels[prio][h]);
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while (t != NULL) {
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while (t != NULL) {
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unregister_netdevice_queue(t->dev, head);
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unregister_netdevice_queue(t->dev, head);
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t = t->next;
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t = rtnl_dereference(t->next);
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}
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}
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}
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}
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}
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}
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