rtnetlink: rtnl_have_link_slave_info doesn't need rtnl

it can be switched to rcu.

Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index d524609c587c1a5ac659fe001b4464341df8dded..e6955da0d58d8d06b138d0519af1f37dfdc0ac5a 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -522,11 +522,15 @@ static size_t rtnl_link_get_af_size(const struct net_device *dev,
 static bool rtnl_have_link_slave_info(const struct net_device *dev)
 {
        struct net_device *master_dev;
+       bool ret = false;
 
-       master_dev = netdev_master_upper_dev_get((struct net_device *) dev);
+       rcu_read_lock();
+
+       master_dev = netdev_master_upper_dev_get_rcu((struct net_device *)dev);
        if (master_dev && master_dev->rtnl_link_ops)
-               return true;
-       return false;
+               ret = true;
+       rcu_read_unlock();
+       return ret;
 }
 
 static int rtnl_link_slave_info_fill(struct sk_buff *skb,