gre: get rid of ipgre_lock
As RTNL is held while doing tunnels inserts and deletes, we can remove ipgre_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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@ -129,7 +129,7 @@ static int ipgre_tunnel_bind_dev(struct net_device *dev);
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static int ipgre_net_id __read_mostly;
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struct ipgre_net {
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struct ip_tunnel *tunnels[4][HASH_SIZE];
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struct ip_tunnel __rcu *tunnels[4][HASH_SIZE];
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struct net_device *fb_tunnel_dev;
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};
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@ -159,9 +159,8 @@ struct ipgre_net {
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#define tunnels_l tunnels[1]
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#define tunnels_wc tunnels[0]
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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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static DEFINE_SPINLOCK(ipgre_lock);
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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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@ -174,8 +173,8 @@ static struct ip_tunnel * ipgre_tunnel_lookup(struct net_device *dev,
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{
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struct net *net = dev_net(dev);
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int link = dev->ifindex;
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unsigned h0 = HASH(remote);
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unsigned h1 = HASH(key);
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unsigned int h0 = HASH(remote);
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unsigned int h1 = HASH(key);
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struct ip_tunnel *t, *cand = NULL;
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struct ipgre_net *ign = net_generic(net, ipgre_net_id);
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int dev_type = (gre_proto == htons(ETH_P_TEB)) ?
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@ -290,13 +289,13 @@ static struct ip_tunnel * ipgre_tunnel_lookup(struct net_device *dev,
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return NULL;
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}
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static struct ip_tunnel **__ipgre_bucket(struct ipgre_net *ign,
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static struct ip_tunnel __rcu **__ipgre_bucket(struct ipgre_net *ign,
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struct ip_tunnel_parm *parms)
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{
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__be32 remote = parms->iph.daddr;
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__be32 local = parms->iph.saddr;
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__be32 key = parms->i_key;
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unsigned h = HASH(key);
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unsigned int h = HASH(key);
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int prio = 0;
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if (local)
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@ -309,7 +308,7 @@ static struct ip_tunnel **__ipgre_bucket(struct ipgre_net *ign,
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return &ign->tunnels[prio][h];
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}
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static inline struct ip_tunnel **ipgre_bucket(struct ipgre_net *ign,
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static inline struct ip_tunnel __rcu **ipgre_bucket(struct ipgre_net *ign,
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struct ip_tunnel *t)
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{
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return __ipgre_bucket(ign, &t->parms);
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@ -317,23 +316,22 @@ static inline struct ip_tunnel **ipgre_bucket(struct ipgre_net *ign,
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static void ipgre_tunnel_link(struct ipgre_net *ign, struct ip_tunnel *t)
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{
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struct ip_tunnel **tp = ipgre_bucket(ign, t);
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struct ip_tunnel __rcu **tp = ipgre_bucket(ign, t);
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spin_lock_bh(&ipgre_lock);
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t->next = *tp;
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rcu_assign_pointer(t->next, rtnl_dereference(*tp));
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rcu_assign_pointer(*tp, t);
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spin_unlock_bh(&ipgre_lock);
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}
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static void ipgre_tunnel_unlink(struct ipgre_net *ign, struct ip_tunnel *t)
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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 = ipgre_bucket(ign, t); *tp; tp = &(*tp)->next) {
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if (t == *tp) {
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spin_lock_bh(&ipgre_lock);
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*tp = t->next;
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spin_unlock_bh(&ipgre_lock);
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for (tp = ipgre_bucket(ign, t);
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(iter = rtnl_dereference(*tp)) != NULL;
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tp = &iter->next) {
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if (t == iter) {
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rcu_assign_pointer(*tp, t->next);
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break;
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}
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}
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@ -347,10 +345,13 @@ static struct ip_tunnel *ipgre_tunnel_find(struct net *net,
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__be32 local = parms->iph.saddr;
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__be32 key = parms->i_key;
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int link = parms->link;
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struct ip_tunnel *t, **tp;
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struct ip_tunnel *t;
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struct ip_tunnel __rcu **tp;
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struct ipgre_net *ign = net_generic(net, ipgre_net_id);
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for (tp = __ipgre_bucket(ign, parms); (t = *tp) != NULL; tp = &t->next)
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for (tp = __ipgre_bucket(ign, 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 &&
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remote == t->parms.iph.daddr &&
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key == t->parms.i_key &&
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@ -1013,7 +1014,7 @@ ipgre_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
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break;
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}
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} else {
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unsigned nflags = 0;
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unsigned int nflags = 0;
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t = netdev_priv(dev);
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@ -1126,7 +1127,7 @@ static int ipgre_tunnel_change_mtu(struct net_device *dev, int new_mtu)
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static int ipgre_header(struct sk_buff *skb, struct net_device *dev,
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unsigned short type,
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const void *daddr, const void *saddr, unsigned len)
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const void *daddr, const void *saddr, unsigned int len)
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{
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struct ip_tunnel *t = netdev_priv(dev);
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struct iphdr *iph = (struct iphdr *)skb_push(skb, t->hlen);
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@ -1275,7 +1276,7 @@ static void ipgre_fb_tunnel_init(struct net_device *dev)
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tunnel->hlen = sizeof(struct iphdr) + 4;
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dev_hold(dev);
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ign->tunnels_wc[0] = tunnel;
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rcu_assign_pointer(ign->tunnels_wc[0], tunnel);
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}
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@ -1291,11 +1292,13 @@ static void ipgre_destroy_tunnels(struct ipgre_net *ign, struct list_head *head)
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for (prio = 0; prio < 4; prio++) {
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int h;
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for (h = 0; h < HASH_SIZE; h++) {
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struct ip_tunnel *t = ign->tunnels[prio][h];
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struct ip_tunnel *t;
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t = rtnl_dereference(ign->tunnels[prio][h]);
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while (t != NULL) {
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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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@ -1522,7 +1525,7 @@ static int ipgre_changelink(struct net_device *dev, struct nlattr *tb[],
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t = nt;
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if (dev->type != ARPHRD_ETHER) {
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unsigned nflags = 0;
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unsigned int nflags = 0;
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if (ipv4_is_multicast(p.iph.daddr))
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nflags = IFF_BROADCAST;
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