tcp: stable backport for 9.3 phase 1
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2188561
A bunch of minor TCP fixes, with no behavioral changes inteded. The only exception is commit 8dda5cd0 ("tcp: minor optimization in tcp_add_backlog()"), which is not a fix but a needed pre-req to avoid conflict in the next one.
Signed-off-by: Paolo Abeni pabeni@redhat.com
Edited by Paolo Abeni