l2tp: simplify pppol2tp_ioctl()
* Drop test on 'sk': sock->sk cannot be NULL, or pppox_ioctl() could
not have called us.
* Drop test on 'SOCK_DEAD' state: if this flag was set, the socket
would be in the process of being released and no ioctl could be
running anymore.
* Drop test on 'PPPOX_*' state: we depend on ->sk_user_data to get
the session structure. If it is non-NULL, then the socket is
connected. Testing for PPPOX_* is redundant.
* Retrieve session using ->sk_user_data directly, instead of going
through pppol2tp_sock_to_session(). This avoids grabbing a useless
reference on the socket.
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>