net: dev_getfirstbyhwtype() optimization

Use RCU to avoid RTNL use in dev_getfirstbyhwtype()

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

diff --git a/net/core/dev.c b/net/core/dev.c
index 2d01f18..a03aab4 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -772,14 +772,17 @@ EXPORT_SYMBOL(__dev_getfirstbyhwtype);
 
 struct net_device *dev_getfirstbyhwtype(struct net *net, unsigned short type)
 {
-       struct net_device *dev;
+       struct net_device *dev, *ret = NULL;
 
-       rtnl_lock();
-       dev = __dev_getfirstbyhwtype(net, type);
-       if (dev)
-               dev_hold(dev);
-       rtnl_unlock();
-       return dev;
+       rcu_read_lock();
+       for_each_netdev_rcu(net, dev)
+               if (dev->type == type) {
+                       dev_hold(dev);
+                       ret = dev;
+                       break;
+               }
+       rcu_read_unlock();
+       return ret;
 }
 EXPORT_SYMBOL(dev_getfirstbyhwtype);