ocfs2/o2net: o2net_listen_data_ready should do nothing if socket state is not TCP_LISTEN

ocfs2/o2net: o2net_listen_data_ready should do nothing if socket state is not TCP_LISTEN

Orabug: 17330860

When accepting an incomming connection o2net_accept_one clones a child
data socket from the parent listening socket.  It then proceeds to setup
the child with callback o2net_data_ready() and sk_user_data to NULL.  If
data arrives in this window, o2net_listen_data_ready will be called with
some non-deterministic value in sk_user_data (not inherited).  We panic
when we page fault on sk_user_data -- in parent it is
sock_def_readable().

The fix is to recognize that this is a data socket being set up by
looking at the socket state and do nothing.

Change-Id: Iffbed59cbec1499e67e6b41ddfdcdc663957c6f5
Signed-off-by: Tariq Saseed <tariq.x.saeed@oracle.com>
Signed-off-by: Srinivas Eeda <srinivas.eeda@oracle.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>