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>

1 files changed, 3 insertions, 3 deletions

diff --git a/net/decnet/af_decnet.c b/net/decnet/af_decnet.c
index 664965c87e16..2e355841ca99 100644
--- a/net/decnet/af_decnet.c
+++ b/net/decnet/af_decnet.c
@@ -749,9 +749,9 @@ static int dn_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 
         if (!(saddr->sdn_flags & SDF_WILD)) {
                 if (le16_to_cpu(saddr->sdn_nodeaddrl)) {
-                        read_lock(&dev_base_lock);
+                        rcu_read_lock();
                         ldev = NULL;
-                        for_each_netdev(&init_net, dev) {
+                        for_each_netdev_rcu(&init_net, dev) {
                                 if (!dev->dn_ptr)
                                         continue;
                                 if (dn_dev_islocal(dev, dn_saddr2dn(saddr))) {
@@ -759,7 +759,7 @@ static int dn_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
                                         break;
                                 }
                         }
-                        read_unlock(&dev_base_lock);
+                        rcu_read_unlock();
                         if (ldev == NULL)
                                 return -EADDRNOTAVAIL;
                 }