Merge branch 'tcp-address-KCSAN-reports-in-tcp_poll-part-I'

Eric Dumazet says:

====================
tcp: address KCSAN reports in tcp_poll() (part I)

This all started with a KCSAN report (included
in "tcp: annotate tp->rcv_nxt lockless reads" changelog)

tcp_poll() runs in a lockless way. This means that about
all accesses of tcp socket fields done in tcp_poll() context
need annotations otherwise KCSAN will complain about data-races.

While doing this detective work, I found a more serious bug,
addressed by the first patch ("tcp: add rcu protection around
tp->fastopen_rsk").
====================

Signed-off-by: David S. Miller <davem@davemloft.net>