[IPV6] ADDRCONF: Convert addrconf_lock to RCU.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 24 insertions, 22 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 825a291d5aa5..c09ebb7bb98a 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -119,9 +119,6 @@ static int ipv6_count_addresses(struct inet6_dev *idev);
 static struct inet6_ifaddr              *inet6_addr_lst[IN6_ADDR_HSIZE];
 static DEFINE_RWLOCK(addrconf_hash_lock);
 
-/* Protects inet6 devices */
-DEFINE_RWLOCK(addrconf_lock);
-
 static void addrconf_verify(unsigned long);
 
 static DEFINE_TIMER(addr_chk_timer, addrconf_verify, 0, 0);
@@ -318,6 +315,12 @@ static void addrconf_mod_timer(struct inet6_ifaddr *ifp,
 
 /* Nobody refers to this device, we may destroy it. */
 
+static void in6_dev_finish_destroy_rcu(struct rcu_head *head)
+{
+        struct inet6_dev *idev = container_of(head, struct inet6_dev, rcu);
+        kfree(idev);
+}
+
 void in6_dev_finish_destroy(struct inet6_dev *idev)
 {
         struct net_device *dev = idev->dev;
@@ -332,7 +335,7 @@ void in6_dev_finish_destroy(struct inet6_dev *idev)
                 return;
         }
         snmp6_free_dev(idev);
-        kfree(idev);
+        call_rcu(&idev->rcu, in6_dev_finish_destroy_rcu);
 }
 
 static struct inet6_dev * ipv6_add_dev(struct net_device *dev)
@@ -408,9 +411,8 @@ static struct inet6_dev * ipv6_add_dev(struct net_device *dev)
         if (netif_carrier_ok(dev))
                 ndev->if_flags |= IF_READY;
 
-        write_lock_bh(&addrconf_lock);
-        dev->ip6_ptr = ndev;
-        write_unlock_bh(&addrconf_lock);
+        /* protected by rtnl_lock */
+        rcu_assign_pointer(dev->ip6_ptr, ndev);
 
         ipv6_mc_init_dev(ndev);
         ndev->tstamp = jiffies;
@@ -474,7 +476,7 @@ static void addrconf_forward_change(void)
 
         read_lock(&dev_base_lock);
         for (dev=dev_base; dev; dev=dev->next) {
-                read_lock(&addrconf_lock);
+                rcu_read_lock();
                 idev = __in6_dev_get(dev);
                 if (idev) {
                         int changed = (!idev->cnf.forwarding) ^ (!ipv6_devconf.forwarding);
@@ -482,7 +484,7 @@ static void addrconf_forward_change(void)
                         if (changed)
                                 dev_forward_change(idev);
                 }
-                read_unlock(&addrconf_lock);
+                rcu_read_unlock();
         }
         read_unlock(&dev_base_lock);
 }
@@ -543,7 +545,7 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr, int pfxlen,
         int hash;
         int err = 0;
 
-        read_lock_bh(&addrconf_lock);
+        rcu_read_lock_bh();
         if (idev->dead) {
                 err = -ENODEV;                  /*XXX*/
                 goto out2;
@@ -612,7 +614,7 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr, int pfxlen,
         in6_ifa_hold(ifa);
         write_unlock(&idev->lock);
 out2:
-        read_unlock_bh(&addrconf_lock);
+        rcu_read_unlock_bh();
 
         if (likely(err == 0))
                 atomic_notifier_call_chain(&inet6addr_chain, NETDEV_UP, ifa);
@@ -915,7 +917,7 @@ int ipv6_dev_get_saddr(struct net_device *daddr_dev,
         memset(&hiscore, 0, sizeof(hiscore));
 
         read_lock(&dev_base_lock);
-        read_lock(&addrconf_lock);
+        rcu_read_lock();
 
         for (dev = dev_base; dev; dev=dev->next) {
                 struct inet6_dev *idev;
@@ -1127,7 +1129,7 @@ record_it:
                 }
                 read_unlock_bh(&idev->lock);
         }
-        read_unlock(&addrconf_lock);
+        rcu_read_unlock();
         read_unlock(&dev_base_lock);
 
         if (!ifa_result)
@@ -1151,7 +1153,7 @@ int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *addr)
         struct inet6_dev *idev;
         int err = -EADDRNOTAVAIL;
 
-        read_lock(&addrconf_lock);
+        rcu_read_lock();
         if ((idev = __in6_dev_get(dev)) != NULL) {
                 struct inet6_ifaddr *ifp;
 
@@ -1165,7 +1167,7 @@ int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *addr)
                 }
                 read_unlock_bh(&idev->lock);
         }
-        read_unlock(&addrconf_lock);
+        rcu_read_unlock();
         return err;
 }
 
@@ -1466,7 +1468,7 @@ static void ipv6_regen_rndid(unsigned long data)
         struct inet6_dev *idev = (struct inet6_dev *) data;
         unsigned long expires;
 
-        read_lock_bh(&addrconf_lock);
+        rcu_read_lock_bh();
         write_lock_bh(&idev->lock);
 
         if (idev->dead)
@@ -1490,7 +1492,7 @@ static void ipv6_regen_rndid(unsigned long data)
 
 out:
         write_unlock_bh(&idev->lock);
-        read_unlock_bh(&addrconf_lock);
+        rcu_read_unlock_bh();
         in6_dev_put(idev);
 }
 
@@ -2342,10 +2344,10 @@ static int addrconf_ifdown(struct net_device *dev, int how)
                    Do not dev_put!
          */
         if (how == 1) {
-                write_lock_bh(&addrconf_lock);
-                dev->ip6_ptr = NULL;
                 idev->dead = 1;
-                write_unlock_bh(&addrconf_lock);
+
+                /* protected by rtnl_lock */
+                rcu_assign_pointer(dev->ip6_ptr, NULL);
 
                 /* Step 1.5: remove snmp6 entry */
                 snmp6_unregister_dev(idev);
@@ -3573,10 +3575,10 @@ static void __ipv6_ifa_notify(int event, struct inet6_ifaddr *ifp)
 
 static void ipv6_ifa_notify(int event, struct inet6_ifaddr *ifp)
 {
-        read_lock_bh(&addrconf_lock);
+        rcu_read_lock_bh();
         if (likely(ifp->idev->dead == 0))
                 __ipv6_ifa_notify(event, ifp);
-        read_unlock_bh(&addrconf_lock);
+        rcu_read_unlock_bh();
 }
 
 #ifdef CONFIG_SYSCTL