net: introduce lockdep_is_held and update various places to use it

The socket is either locked if we hold the slock spin_lock for
lock_sock_fast and unlock_sock_fast or we own the lock (sk_lock.owned
!= 0). Check for this and at the same time improve that the current
thread/cpu is really holding the lock.

Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index a5557d2..4ff4b29 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -407,7 +407,8 @@
 		if (optname != IPV6_RTHDR && !ns_capable(net->user_ns, CAP_NET_RAW))
 			break;
 
-		opt = rcu_dereference_protected(np->opt, sock_owned_by_user(sk));
+		opt = rcu_dereference_protected(np->opt,
+						lockdep_sock_is_held(sk));
 		opt = ipv6_renew_options(sk, opt, optname,
 					 (struct ipv6_opt_hdr __user *)optval,
 					 optlen);
@@ -1124,7 +1125,8 @@
 		struct ipv6_txoptions *opt;
 
 		lock_sock(sk);
-		opt = rcu_dereference_protected(np->opt, sock_owned_by_user(sk));
+		opt = rcu_dereference_protected(np->opt,
+						lockdep_sock_is_held(sk));
 		len = ipv6_getsockopt_sticky(sk, opt, optname, optval, len);
 		release_sock(sk);
 		/* check if ipv6_getsockopt_sticky() returns err code */