UPSTREAM: tcp: fix access to sk->sk_state in tcp_poll()

commit d68be71ea14d609a5f31534003319be5db422595 upstream.

avoid direct access to sk->sk_state when tcp_poll() is called on a socket
using active TCP fastopen with deferred connect. Use local variable
'state', which stores the result of sk_state_load(), like it was done in
commit 00fd38d9 ("tcp: ensure proper barriers in lockless contexts").

Fixes: 19f6d3f3c842 ("net/tcp-fastopen: Add new API support")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Acked-by: Wei Wang <weiwan@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Change-Id: I5f5510a070a3d634bac28c4edbb64e362bab59b0
Fixes: Change-Id: Icc181febd74e3117c2fc835d7ed935e107b5815e
       ("BACKPORT: net/tcp-fastopen: Add new API support")
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>