[PATCH v2] net/sock: Update sk rcu iterator macro.

[Tim Hansen]

Mark hlist nodes in sk rcu iterator as protected by the rcu.
hlist_next_rcu accomplishes this and silences the warnings
sparse throws for net/ipv4/udp.c and net/ipv6/udp.c.

Found with make C=1 net/ipv4/udp.o on linux-next tag 
next-20171009.

Signed-off-by: Tim Hansen <devtimhan...@gmail.com>
---
 include/net/sock.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index 64e5ac41b9cf..96cb7b7e4924 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -737,10 +737,10 @@ static inline void sk_add_bind_node(struct sock *sk,
  *
  */
 #define sk_for_each_entry_offset_rcu(tpos, pos, head, offset)                 \
-       for (pos = rcu_dereference((head)->first);                             \
+       for (pos = rcu_dereference(hlist_next_rcu((head)->first));             \
             pos != NULL &&                                                    \
                ({ tpos = (typeof(*tpos) *)((void *)pos - offset); 1;});       \
-            pos = rcu_dereference(pos->next))
+            pos = rcu_dereference(hlist_next_rcu(pos->next)))
 
 static inline struct user_namespace *sk_user_ns(struct sock *sk)
 {
-- 
2.15.0.rc0