net: net_families __rcu annotations

Use modern RCU API / annotations for net_families array.

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

diff --git a/net/socket.c b/net/socket.c
index 3ca2fd9e37200e3e12f6606065acb8c982f25528..c898df76e924f3d9a0e51f1c102f65018ab16e84 100644 (file)
--- a/net/socket.c
+++ b/net/socket.c
@@ -156,7 +156,7 @@ static const struct file_operations socket_file_ops = {
  */
 
 static DEFINE_SPINLOCK(net_family_lock);
-static const struct net_proto_family *net_families[NPROTO] __read_mostly;
+static const struct net_proto_family __rcu *net_families[NPROTO] __read_mostly;
 
 /*
  *     Statistics counters of the socket lists
@@ -1200,7 +1200,7 @@ int __sock_create(struct net *net, int family, int type, int protocol,
         * requested real, full-featured networking support upon configuration.
         * Otherwise module support will break!
         */
-       if (net_families[family] == NULL)
+       if (rcu_access_pointer(net_families[family]) == NULL)
                request_module("net-pf-%d", family);
 #endif
 
@@ -2332,10 +2332,11 @@ int sock_register(const struct net_proto_family *ops)
        }
 
        spin_lock(&net_family_lock);
-       if (net_families[ops->family])
+       if (rcu_dereference_protected(net_families[ops->family],
+                                     lockdep_is_held(&net_family_lock)))
                err = -EEXIST;
        else {
-               net_families[ops->family] = ops;
+               rcu_assign_pointer(net_families[ops->family], ops);
                err = 0;
        }
        spin_unlock(&net_family_lock);
@@ -2363,7 +2364,7 @@ void sock_unregister(int family)
        BUG_ON(family < 0 || family >= NPROTO);
 
        spin_lock(&net_family_lock);
-       net_families[family] = NULL;
+       rcu_assign_pointer(net_families[family], NULL);
        spin_unlock(&net_family_lock);
 
        synchronize_rcu();