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>

2 files changed, 18 insertions, 11 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);
diff --git a/net/ipv6/tunnel6.c b/net/ipv6/tunnel6.c
index d9864725d0c6..4f3cec12aa85 100644
--- a/net/ipv6/tunnel6.c
+++ b/net/ipv6/tunnel6.c
@@ -30,23 +30,26 @@
 #include <net/protocol.h>
 #include <net/xfrm.h>
 
-static struct xfrm6_tunnel *tunnel6_handlers __read_mostly;
-static struct xfrm6_tunnel *tunnel46_handlers __read_mostly;
+static struct xfrm6_tunnel __rcu *tunnel6_handlers __read_mostly;
+static struct xfrm6_tunnel __rcu *tunnel46_handlers __read_mostly;
 static DEFINE_MUTEX(tunnel6_mutex);
 
 int xfrm6_tunnel_register(struct xfrm6_tunnel *handler, unsigned short family)
 {
-        struct xfrm6_tunnel **pprev;
+        struct xfrm6_tunnel __rcu **pprev;
+        struct xfrm6_tunnel *t;
         int ret = -EEXIST;
         int priority = handler->priority;
 
         mutex_lock(&tunnel6_mutex);
 
         for (pprev = (family == AF_INET6) ? &tunnel6_handlers : &tunnel46_handlers;
-             *pprev; pprev = &(*pprev)->next) {
-                if ((*pprev)->priority > priority)
+             (t = rcu_dereference_protected(*pprev,
+                        lockdep_is_held(&tunnel6_mutex))) != NULL;
+             pprev = &t->next) {
+                if (t->priority > priority)
                         break;
-                if ((*pprev)->priority == priority)
+                if (t->priority == priority)
                         goto err;
         }
 
@@ -65,14 +68,17 @@ EXPORT_SYMBOL(xfrm6_tunnel_register);
 
 int xfrm6_tunnel_deregister(struct xfrm6_tunnel *handler, unsigned short family)
 {
-        struct xfrm6_tunnel **pprev;
+        struct xfrm6_tunnel __rcu **pprev;
+        struct xfrm6_tunnel *t;
         int ret = -ENOENT;
 
         mutex_lock(&tunnel6_mutex);
 
         for (pprev = (family == AF_INET6) ? &tunnel6_handlers : &tunnel46_handlers;
-             *pprev; pprev = &(*pprev)->next) {
-                if (*pprev == handler) {
+             (t = rcu_dereference_protected(*pprev,
+                        lockdep_is_held(&tunnel6_mutex))) != NULL;
+             pprev = &t->next) {
+                if (t == handler) {
                         *pprev = handler->next;
                         ret = 0;
                         break;