1 files changed, 28 insertions, 21 deletions

diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c
index 6a5539236ab3..3bd69988bccf 100644
--- a/net/ipv4/ipip.c
+++ b/net/ipv4/ipip.c
@@ -134,7 +134,13 @@ static void ipip_fb_tunnel_init(struct net_device *dev);
 static void ipip_tunnel_init(struct net_device *dev);
 static void ipip_tunnel_setup(struct net_device *dev);
 
-static DEFINE_RWLOCK(ipip_lock);
+/*
+ * Locking : hash tables are protected by RCU and a spinlock
+ */
+static DEFINE_SPINLOCK(ipip_lock);
+
+#define for_each_ip_tunnel_rcu(start) \
+        for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
 
 static struct ip_tunnel * ipip_tunnel_lookup(struct net *net,
                 __be32 remote, __be32 local)
@@ -144,20 +150,21 @@ static struct ip_tunnel * ipip_tunnel_lookup(struct net *net,
         struct ip_tunnel *t;
         struct ipip_net *ipn = net_generic(net, ipip_net_id);
 
-        for (t = ipn->tunnels_r_l[h0^h1]; t; t = t->next) {
+        for_each_ip_tunnel_rcu(ipn->tunnels_r_l[h0 ^ h1])
                 if (local == t->parms.iph.saddr &&
                     remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
                         return t;
-        }
-        for (t = ipn->tunnels_r[h0]; t; t = t->next) {
+
+        for_each_ip_tunnel_rcu(ipn->tunnels_r[h0])
                 if (remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
                         return t;
-        }
-        for (t = ipn->tunnels_l[h1]; t; t = t->next) {
+
+        for_each_ip_tunnel_rcu(ipn->tunnels_l[h1])
                 if (local == t->parms.iph.saddr && (t->dev->flags&IFF_UP))
                         return t;
-        }
-        if ((t = ipn->tunnels_wc[0]) != NULL && (t->dev->flags&IFF_UP))
+
+        t = rcu_dereference(ipn->tunnels_wc[0]);
+        if (t && (t->dev->flags&IFF_UP))
                 return t;
         return NULL;
 }
@@ -193,9 +200,9 @@ static void ipip_tunnel_unlink(struct ipip_net *ipn, struct ip_tunnel *t)
 
         for (tp = ipip_bucket(ipn, t); *tp; tp = &(*tp)->next) {
                 if (t == *tp) {
-                        write_lock_bh(&ipip_lock);
+                        spin_lock_bh(&ipip_lock);
                         *tp = t->next;
-                        write_unlock_bh(&ipip_lock);
+                        spin_unlock_bh(&ipip_lock);
                         break;
                 }
         }
@@ -205,10 +212,10 @@ static void ipip_tunnel_link(struct ipip_net *ipn, struct ip_tunnel *t)
 {
         struct ip_tunnel **tp = ipip_bucket(ipn, t);
 
+        spin_lock_bh(&ipip_lock);
         t->next = *tp;
-        write_lock_bh(&ipip_lock);
-        *tp = t;
-        write_unlock_bh(&ipip_lock);
+        rcu_assign_pointer(*tp, t);
+        spin_unlock_bh(&ipip_lock);
 }
 
 static struct ip_tunnel * ipip_tunnel_locate(struct net *net,
@@ -267,9 +274,9 @@ static void ipip_tunnel_uninit(struct net_device *dev)
         struct ipip_net *ipn = net_generic(net, ipip_net_id);
 
         if (dev == ipn->fb_tunnel_dev) {
-                write_lock_bh(&ipip_lock);
+                spin_lock_bh(&ipip_lock);
                 ipn->tunnels_wc[0] = NULL;
-                write_unlock_bh(&ipip_lock);
+                spin_unlock_bh(&ipip_lock);
         } else
                 ipip_tunnel_unlink(ipn, netdev_priv(dev));
         dev_put(dev);
@@ -318,7 +325,7 @@ static int ipip_err(struct sk_buff *skb, u32 info)
 
         err = -ENOENT;
 
-        read_lock(&ipip_lock);
+        rcu_read_lock();
         t = ipip_tunnel_lookup(dev_net(skb->dev), iph->daddr, iph->saddr);
         if (t == NULL || t->parms.iph.daddr == 0)
                 goto out;
@@ -333,7 +340,7 @@ static int ipip_err(struct sk_buff *skb, u32 info)
                 t->err_count = 1;
         t->err_time = jiffies;
 out:
-        read_unlock(&ipip_lock);
+        rcu_read_unlock();
         return err;
 }
 
@@ -351,11 +358,11 @@ static int ipip_rcv(struct sk_buff *skb)
         struct ip_tunnel *tunnel;
         const struct iphdr *iph = ip_hdr(skb);
 
-        read_lock(&ipip_lock);
+        rcu_read_lock();
         if ((tunnel = ipip_tunnel_lookup(dev_net(skb->dev),
                                         iph->saddr, iph->daddr)) != NULL) {
                 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
-                        read_unlock(&ipip_lock);
+                        rcu_read_unlock();
                         kfree_skb(skb);
                         return 0;
                 }
@@ -374,10 +381,10 @@ static int ipip_rcv(struct sk_buff *skb)
                 nf_reset(skb);
                 ipip_ecn_decapsulate(iph, skb);
                 netif_rx(skb);
-                read_unlock(&ipip_lock);
+                rcu_read_unlock();
                 return 0;
         }
-        read_unlock(&ipip_lock);
+        rcu_read_unlock();
 
         return -1;
 }