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>

1 files changed, 10 insertions, 7 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 2d01f18f303a..a03aab45e84f 100644
--- 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);