Merge branch 'tipc-next'

Jon Maloy says:

====================
tipc: improve broadcast implementation

The TIPC broadcast link implementation is currently complex and hard to
follow. It also incurs some amount of code and structure duplication,
something that can be reduced significantly with a little effort.

This commit series introduces a number of improvements which address
both the locking structure, the code/structure duplication issue, and
the overall readbility of the code.

The series consists of three main parts:

1-7: Adaptation to the new link structure, and preparation for the next
     step. In particular, we want the broadcast transmission link to
     have a life cycle that is longer than any of its potential (unicast
     and broadcast receive links) users. This eliminates the need to
     always test for the presence of this link before accessing it.

8-10: This is what is really new in this series. Commit #9 is by far
      the largest and most important one, because it moves most of
      the broadcast functionality into link.c, partially reusing the
      fields and functionality of the unicast link. The removal of
      the "node_map" infrastructure in commit #10 is also an important
      achievement.

11-16: Some improvements leveraging the changes made in the previous
       commits.

The series needs commit 53387c4e22ac ("tipc: extend broadcast link window size")
and commit e53567948f82 ("tipc: conditionally expand buffer headroom over udp tunnel")
which are both present in 'net' but not yet in 'net-next', to apply cleanly.
====================

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