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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2010-04-27 06:22:01 +0000
committerDavid S. Miller <davem@davemloft.net>2010-04-27 12:39:01 -0700
commit7ec75c582e639d956ce3afd499f67febe6f902a4 (patch)
tree4752d1cc90ab385797d526cb901e42f27e3b20f6 /include
parentd4c4f07df16c767b8efbc44e7cdf795fac326b33 (diff)
downloadlinux-7ec75c582e639d956ce3afd499f67febe6f902a4.tar.gz
net: suppress RCU lockdep false positive in twsk_net()
Calls to twsk_net() are in some cases protected by reference counting
as an alternative to RCU protection.  Cases covered by reference counts
include __inet_twsk_kill(), inet_twsk_free(), inet_twdr_do_twkill_work(),
inet_twdr_twcal_tick(), and tcp_timewait_state_process().  RCU is used
by inet_twsk_purge().  Locking is used by established_get_first()
and established_get_next().  Finally, __inet_twsk_hashdance() is an
initialization case.

It appears to be non-trivial to locate the appropriate locks and
reference counts from within twsk_net(), so used rcu_dereference_raw().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
-rw-r--r--include/net/inet_timewait_sock.h4
1 files changed, 3 insertions, 1 deletions
diff --git a/include/net/inet_timewait_sock.h b/include/net/inet_timewait_sock.h
index 79f67eae8a7e..a066fdd50da6 100644
--- a/include/net/inet_timewait_sock.h
+++ b/include/net/inet_timewait_sock.h
@@ -224,7 +224,9 @@ static inline
 struct net *twsk_net(const struct inet_timewait_sock *twsk)
 {
 #ifdef CONFIG_NET_NS
-	return rcu_dereference(twsk->tw_net);
+	return rcu_dereference_raw(twsk->tw_net); /* protected by locking, */
+						  /* reference counting, */
+						  /* initialization, or RCU. */
 #else
 	return &init_net;
 #endif