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/sctp/protocol.c b/net/sctp/protocol.c
index d9f4cc2c7869..fe44c57101de 100644
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -205,14 +205,14 @@ static void sctp_get_local_addr_list(void)
         struct list_head *pos;
         struct sctp_af *af;
 
-        read_lock(&dev_base_lock);
-        for_each_netdev(&init_net, dev) {
+        rcu_read_lock();
+        for_each_netdev_rcu(&init_net, dev) {
                 __list_for_each(pos, &sctp_address_families) {
                         af = list_entry(pos, struct sctp_af, list);
                         af->copy_addrlist(&sctp_local_addr_list, dev);
                 }
         }
-        read_unlock(&dev_base_lock);
+        rcu_read_unlock();
 }
 
 /* Free the existing local addresses.  */