commit c6d14c84566d6b70ad9dc1618db0dec87cca9300
author Eric Dumazet <eric.dumazet@gmail.com> Wed Nov 04 05:43:23 2009 -0800
committer David S. Miller <davem@davemloft.net> Wed Nov 04 05:43:23 2009 -0800
tree 5ec75245cfda4d61e6b4506b6217f047ff4af01a
parent d0075634cf9d288988f57392a1f132d2053af961

net: Introduce for_each_netdev_rcu() iterator

Adds RCU management to the list of netdevices.

Convert some for_each_netdev() users to RCU version, if
it can avoid read_lock-ing dev_base_lock

Ie:
	read_lock(&dev_base_loack);
	for_each_netdev(net, dev)
		some_action();
	read_unlock(&dev_base_lock);

becomes :

	rcu_read_lock();
	for_each_netdev_rcu(net, dev)
		some_action();
	rcu_read_unlock();


Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/addrconf.c

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 9186484..024bba3 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -481,9 +481,8 @@
 	struct net_device *dev;
 	struct inet6_dev *idev;
 
-	read_lock(&dev_base_lock);
-	for_each_netdev(net, dev) {
-		rcu_read_lock();
+	rcu_read_lock();
+	for_each_netdev_rcu(net, dev) {
 		idev = __in6_dev_get(dev);
 		if (idev) {
 			int changed = (!idev->cnf.forwarding) ^ (!newf);
@@ -491,9 +490,8 @@
 			if (changed)
 				dev_forward_change(idev);
 		}
-		rcu_read_unlock();
 	}
-	read_unlock(&dev_base_lock);
+	rcu_read_unlock();
 }
 
 static int addrconf_fixup_forwarding(struct ctl_table *table, int *p, int old)
@@ -1137,10 +1135,9 @@
 	hiscore->rule = -1;
 	hiscore->ifa = NULL;
 
-	read_lock(&dev_base_lock);
 	rcu_read_lock();
 
-	for_each_netdev(net, dev) {
+	for_each_netdev_rcu(net, dev) {
 		struct inet6_dev *idev;
 
 		/* Candidate Source Address (section 4)
@@ -1235,7 +1232,6 @@
 		read_unlock_bh(&idev->lock);
 	}
 	rcu_read_unlock();
-	read_unlock(&dev_base_lock);
 
 	if (!hiscore->ifa)
 		return -EADDRNOTAVAIL;
@@ -4052,9 +4048,8 @@
 	struct net_device *dev;
 	struct inet6_dev *idev;
 
-	read_lock(&dev_base_lock);
-	for_each_netdev(net, dev) {
-		rcu_read_lock();
+	rcu_read_lock();
+	for_each_netdev_rcu(net, dev) {
 		idev = __in6_dev_get(dev);
 		if (idev) {
 			int changed = (!idev->cnf.disable_ipv6) ^ (!newf);
@@ -4062,9 +4057,8 @@
 			if (changed)
 				dev_disable_change(idev);
 		}
-		rcu_read_unlock();
 	}
-	read_unlock(&dev_base_lock);
+	rcu_read_unlock();
 }
 
 static int addrconf_disable_ipv6(struct ctl_table *table, int *p, int old)