tunnels: add __rcu annotations
Eric Dumazet [Mon, 25 Oct 2010 21:01:26 +0000 (21:01 +0000)]
Add __rcu annotations to :
        (struct ip_tunnel)->prl
        (struct ip_tunnel_prl_entry)->next
        (struct xfrm_tunnel)->next
struct xfrm_tunnel *tunnel4_handlers
struct xfrm_tunnel *tunnel64_handlers

And use appropriate rcu primitives to reduce sparse warnings if
CONFIG_SPARSE_RCU_POINTER=y

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

include/net/ipip.h
include/net/xfrm.h
net/ipv4/tunnel4.c

index 0403fe4..a32654d 100644 (file)
@@ -34,12 +34,12 @@ struct ip_tunnel {
 #ifdef CONFIG_IPV6_SIT_6RD
        struct ip_tunnel_6rd_parm       ip6rd;
 #endif
-       struct ip_tunnel_prl_entry      *prl;           /* potential router list */
+       struct ip_tunnel_prl_entry __rcu *prl;          /* potential router list */
        unsigned int                    prl_count;      /* # of entries in PRL */
 };
 
 struct ip_tunnel_prl_entry {
-       struct ip_tunnel_prl_entry      *next;
+       struct ip_tunnel_prl_entry __rcu *next;
        __be32                          addr;
        u16                             flags;
        struct rcu_head                 rcu_head;
index ffcd478..bcfb6b2 100644 (file)
@@ -1264,7 +1264,7 @@ struct xfrm_tunnel {
        int (*handler)(struct sk_buff *skb);
        int (*err_handler)(struct sk_buff *skb, u32 info);
 
-       struct xfrm_tunnel *next;
+       struct xfrm_tunnel __rcu *next;
        int priority;
 };
 
index 9a17bd2..ac3b3ee 100644 (file)
 #include <net/protocol.h>
 #include <net/xfrm.h>
 
-static struct xfrm_tunnel *tunnel4_handlers __read_mostly;
-static struct xfrm_tunnel *tunnel64_handlers __read_mostly;
+static struct xfrm_tunnel __rcu *tunnel4_handlers __read_mostly;
+static struct xfrm_tunnel __rcu *tunnel64_handlers __read_mostly;
 static DEFINE_MUTEX(tunnel4_mutex);
 
-static inline struct xfrm_tunnel **fam_handlers(unsigned short family)
+static inline struct xfrm_tunnel __rcu **fam_handlers(unsigned short family)
 {
        return (family == AF_INET) ? &tunnel4_handlers : &tunnel64_handlers;
 }
 
 int xfrm4_tunnel_register(struct xfrm_tunnel *handler, unsigned short family)
 {
-       struct xfrm_tunnel **pprev;
+       struct xfrm_tunnel __rcu **pprev;
+       struct xfrm_tunnel *t;
+
        int ret = -EEXIST;
        int priority = handler->priority;
 
        mutex_lock(&tunnel4_mutex);
 
-       for (pprev = fam_handlers(family); *pprev; pprev = &(*pprev)->next) {
-               if ((*pprev)->priority > priority)
+       for (pprev = fam_handlers(family);
+            (t = rcu_dereference_protected(*pprev,
+                       lockdep_is_held(&tunnel4_mutex))) != NULL;
+            pprev = &t->next) {
+               if (t->priority > priority)
                        break;
-               if ((*pprev)->priority == priority)
+               if (t->priority == priority)
                        goto err;
        }
 
@@ -52,13 +57,17 @@ EXPORT_SYMBOL(xfrm4_tunnel_register);
 
 int xfrm4_tunnel_deregister(struct xfrm_tunnel *handler, unsigned short family)
 {
-       struct xfrm_tunnel **pprev;
+       struct xfrm_tunnel __rcu **pprev;
+       struct xfrm_tunnel *t;
        int ret = -ENOENT;
 
        mutex_lock(&tunnel4_mutex);
 
-       for (pprev = fam_handlers(family); *pprev; pprev = &(*pprev)->next) {
-               if (*pprev == handler) {
+       for (pprev = fam_handlers(family);
+            (t = rcu_dereference_protected(*pprev,
+                       lockdep_is_held(&tunnel4_mutex))) != NULL;
+            pprev = &t->next) {
+               if (t == handler) {
                        *pprev = handler->next;
                        ret = 0;
                        break;