tunnels: add _rcu annotations

(struct ip6_tnl)->next is rcu protected :
(struct ip_tunnel)->next is rcu protected :
(struct xfrm6_tunnel)->next is rcu protected :

add __rcu annotation and proper rcu primitives.

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

1 files changed, 3 insertions, 2 deletions

diff --git a/net/ipv4/gre.c b/net/ipv4/gre.c
index caea6885fdbd..c6933f2ea310 100644
--- a/net/ipv4/gre.c
+++ b/net/ipv4/gre.c
@@ -22,7 +22,7 @@
 #include <net/gre.h>
 
 
-static const struct gre_protocol *gre_proto[GREPROTO_MAX] __read_mostly;
+static const struct gre_protocol __rcu *gre_proto[GREPROTO_MAX] __read_mostly;
 static DEFINE_SPINLOCK(gre_proto_lock);
 
 int gre_add_protocol(const struct gre_protocol *proto, u8 version)
@@ -51,7 +51,8 @@ int gre_del_protocol(const struct gre_protocol *proto, u8 version)
                 goto err_out;
 
         spin_lock(&gre_proto_lock);
-        if (gre_proto[version] != proto)
+        if (rcu_dereference_protected(gre_proto[version],
+                        lockdep_is_held(&gre_proto_lock)) != proto)
                 goto err_out_unlock;
         rcu_assign_pointer(gre_proto[version], NULL);
         spin_unlock(&gre_proto_lock);