From: Eric Dumazet Date: Wed, 15 Sep 2010 11:07:53 +0000 (+0000) Subject: gre: get rid of ipgre_lock X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=1507850b400492fdedc3064d3b8db5e9a1c871e3;p=linux-beck.git 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 Signed-off-by: David S. Miller --- diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c index 85176895495a..fc20e687e933 100644 --- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -129,7 +129,7 @@ static int ipgre_tunnel_bind_dev(struct net_device *dev); static int ipgre_net_id __read_mostly; struct ipgre_net { - struct ip_tunnel *tunnels[4][HASH_SIZE]; + struct ip_tunnel __rcu *tunnels[4][HASH_SIZE]; struct net_device *fb_tunnel_dev; }; @@ -159,9 +159,8 @@ struct ipgre_net { #define tunnels_l tunnels[1] #define tunnels_wc tunnels[0] /* - * Locking : hash tables are protected by RCU and a spinlock + * Locking : hash tables are protected by RCU and RTNL */ -static DEFINE_SPINLOCK(ipgre_lock); #define for_each_ip_tunnel_rcu(start) \ for (t = rcu_dereference(start); t; t = rcu_dereference(t->next)) @@ -174,8 +173,8 @@ static struct ip_tunnel * ipgre_tunnel_lookup(struct net_device *dev, { struct net *net = dev_net(dev); int link = dev->ifindex; - unsigned h0 = HASH(remote); - unsigned h1 = HASH(key); + unsigned int h0 = HASH(remote); + unsigned int h1 = HASH(key); struct ip_tunnel *t, *cand = NULL; struct ipgre_net *ign = net_generic(net, ipgre_net_id); int dev_type = (gre_proto == htons(ETH_P_TEB)) ? @@ -290,13 +289,13 @@ static struct ip_tunnel * ipgre_tunnel_lookup(struct net_device *dev, return NULL; } -static struct ip_tunnel **__ipgre_bucket(struct ipgre_net *ign, +static struct ip_tunnel __rcu **__ipgre_bucket(struct ipgre_net *ign, struct ip_tunnel_parm *parms) { __be32 remote = parms->iph.daddr; __be32 local = parms->iph.saddr; __be32 key = parms->i_key; - unsigned h = HASH(key); + unsigned int h = HASH(key); int prio = 0; if (local) @@ -309,7 +308,7 @@ static struct ip_tunnel **__ipgre_bucket(struct ipgre_net *ign, return &ign->tunnels[prio][h]; } -static inline struct ip_tunnel **ipgre_bucket(struct ipgre_net *ign, +static inline struct ip_tunnel __rcu **ipgre_bucket(struct ipgre_net *ign, struct ip_tunnel *t) { return __ipgre_bucket(ign, &t->parms); @@ -317,23 +316,22 @@ static inline struct ip_tunnel **ipgre_bucket(struct ipgre_net *ign, static void ipgre_tunnel_link(struct ipgre_net *ign, struct ip_tunnel *t) { - struct ip_tunnel **tp = ipgre_bucket(ign, t); + struct ip_tunnel __rcu **tp = ipgre_bucket(ign, t); - spin_lock_bh(&ipgre_lock); - t->next = *tp; + rcu_assign_pointer(t->next, rtnl_dereference(*tp)); rcu_assign_pointer(*tp, t); - spin_unlock_bh(&ipgre_lock); } static void ipgre_tunnel_unlink(struct ipgre_net *ign, struct ip_tunnel *t) { - struct ip_tunnel **tp; - - for (tp = ipgre_bucket(ign, t); *tp; tp = &(*tp)->next) { - if (t == *tp) { - spin_lock_bh(&ipgre_lock); - *tp = t->next; - spin_unlock_bh(&ipgre_lock); + struct ip_tunnel __rcu **tp; + struct ip_tunnel *iter; + + for (tp = ipgre_bucket(ign, t); + (iter = rtnl_dereference(*tp)) != NULL; + tp = &iter->next) { + if (t == iter) { + rcu_assign_pointer(*tp, t->next); break; } } @@ -347,10 +345,13 @@ static struct ip_tunnel *ipgre_tunnel_find(struct net *net, __be32 local = parms->iph.saddr; __be32 key = parms->i_key; int link = parms->link; - struct ip_tunnel *t, **tp; + struct ip_tunnel *t; + struct ip_tunnel __rcu **tp; struct ipgre_net *ign = net_generic(net, ipgre_net_id); - for (tp = __ipgre_bucket(ign, parms); (t = *tp) != NULL; tp = &t->next) + for (tp = __ipgre_bucket(ign, parms); + (t = rtnl_dereference(*tp)) != NULL; + tp = &t->next) if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr && key == t->parms.i_key && @@ -361,7 +362,7 @@ static struct ip_tunnel *ipgre_tunnel_find(struct net *net, return t; } -static struct ip_tunnel * ipgre_tunnel_locate(struct net *net, +static struct ip_tunnel *ipgre_tunnel_locate(struct net *net, struct ip_tunnel_parm *parms, int create) { struct ip_tunnel *t, *nt; @@ -669,7 +670,7 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev u8 tos; __be16 df; struct rtable *rt; /* Route to the other host */ - struct net_device *tdev; /* Device to other host */ + struct net_device *tdev; /* Device to other host */ struct iphdr *iph; /* Our new IP header */ unsigned int max_headroom; /* The extra header space needed */ int gre_hlen; @@ -1013,7 +1014,7 @@ ipgre_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd) break; } } else { - unsigned nflags = 0; + unsigned int nflags = 0; t = netdev_priv(dev); @@ -1126,7 +1127,7 @@ static int ipgre_tunnel_change_mtu(struct net_device *dev, int new_mtu) static int ipgre_header(struct sk_buff *skb, struct net_device *dev, unsigned short type, - const void *daddr, const void *saddr, unsigned len) + const void *daddr, const void *saddr, unsigned int len) { struct ip_tunnel *t = netdev_priv(dev); struct iphdr *iph = (struct iphdr *)skb_push(skb, t->hlen); @@ -1275,7 +1276,7 @@ static void ipgre_fb_tunnel_init(struct net_device *dev) tunnel->hlen = sizeof(struct iphdr) + 4; dev_hold(dev); - ign->tunnels_wc[0] = tunnel; + rcu_assign_pointer(ign->tunnels_wc[0], tunnel); } @@ -1291,11 +1292,13 @@ static void ipgre_destroy_tunnels(struct ipgre_net *ign, struct list_head *head) for (prio = 0; prio < 4; prio++) { int h; for (h = 0; h < HASH_SIZE; h++) { - struct ip_tunnel *t = ign->tunnels[prio][h]; + struct ip_tunnel *t; + + t = rtnl_dereference(ign->tunnels[prio][h]); while (t != NULL) { unregister_netdevice_queue(t->dev, head); - t = t->next; + t = rtnl_dereference(t->next); } } } @@ -1522,7 +1525,7 @@ static int ipgre_changelink(struct net_device *dev, struct nlattr *tb[], t = nt; if (dev->type != ARPHRD_ETHER) { - unsigned nflags = 0; + unsigned int nflags = 0; if (ipv4_is_multicast(p.iph.daddr)) nflags = IFF_BROADCAST;