sctp: Add RCU protection to assoc->transport_addr_list

peer.transport_addr_list is currently only protected by sk_sock
which is inpractical to acquire for procfs dumping purposes.

This patch adds RCU protection allowing for the procfs readers to
enter RCU read-side critical sections.

Modification of the list continues to be serialized via sk_lock.

V2: Use list_del_rcu() in sctp_association_free() to be safe
    Skip transports marked dead when dumping for procfs

Cc: Vlad Yasevich <vyasevich@gmail.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index c2521016d64..fdeb85a970f 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -949,6 +949,8 @@ struct sctp_transport {
 
         /* 64-bit random number sent with heartbeat. */
         __u64 hb_nonce;
+
+        struct rcu_head rcu;
 };
 
 struct sctp_transport *sctp_transport_new(struct net *, const union sctp_addr *,