net: add RCU variant to search for netdev_adjacent link

Currently we have only the RTNL flavour, however we can traverse it while
holding only RCU, so add the RCU search. Add an RCU variant that uses
list_head * as an argument, so that it can be universally used afterwards.

CC: "David S. Miller" <davem@davemloft.net>
CC: Eric Dumazet <edumazet@google.com>
CC: Jiri Pirko <jiri@resnulli.us>
CC: Alexander Duyck <alexander.h.duyck@intel.com>
CC: Cong Wang <amwang@redhat.com>
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/dev.c b/net/core/dev.c
index 9a395e03da74e45acaefc4f22d3e1732841baea1..9290f09cdf26ee9c03817a2c8045f32f30a0290d 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4380,6 +4380,19 @@ struct netdev_adjacent {
        struct rcu_head rcu;
 };
 
+static struct netdev_adjacent *__netdev_find_adj_rcu(struct net_device *dev,
+                                                    struct net_device *adj_dev,
+                                                    struct list_head *adj_list)
+{
+       struct netdev_adjacent *adj;
+
+       list_for_each_entry_rcu(adj, adj_list, list) {
+               if (adj->dev == adj_dev)
+                       return adj;
+       }
+       return NULL;
+}
+
 static struct netdev_adjacent *__netdev_find_adj(struct net_device *dev,
                                                 struct net_device *adj_dev,
                                                 struct list_head *adj_list)