[IPV6] lockdep: annotate __icmpv6_socket

Split off __icmpv6_socket's sk->sk_dst_lock class, because it gets
used from softirqs, which is safe for __icmpv6_sockets (because they
never get directly used via userspace syscalls), but unsafe for normal
sockets.

Has no effect on non-lockdep kernels.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 13 insertions, 0 deletions

diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 1044b6fce0d5..3d6e9a351150 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -712,6 +712,11 @@ discard_it:
         return 0;
 }
 
+/*
+ * Special lock-class for __icmpv6_socket:
+ */
+static struct lock_class_key icmpv6_socket_sk_dst_lock_key;
+
 int __init icmpv6_init(struct net_proto_family *ops)
 {
         struct sock *sk;
@@ -730,6 +735,14 @@ int __init icmpv6_init(struct net_proto_family *ops)
 
                 sk = per_cpu(__icmpv6_socket, i)->sk;
                 sk->sk_allocation = GFP_ATOMIC;
+                /*
+                 * Split off their lock-class, because sk->sk_dst_lock
+                 * gets used from softirqs, which is safe for
+                 * __icmpv6_socket (because those never get directly used
+                 * via userspace syscalls), but unsafe for normal sockets.
+                 */
+                lockdep_set_class(&sk->sk_dst_lock,
+                                  &icmpv6_socket_sk_dst_lock_key);
 
                 /* Enough space for 2 64K ICMP packets, including
                  * sk_buff struct overhead.