Merge branch 'resil-nhgroups-netdevsim-selftests'

Merge branch 'resil-nhgroups-netdevsim-selftests'

Petr Machata says:

====================
net: Resilient NH groups: netdevsim, selftests

Support for resilient next-hop groups was added in a previous patch set.
Resilient next hop groups add a layer of indirection between the SKB hash
and the next hop. Thus the hash is used to reference a hash table bucket,
which is then used to reference a particular next hop. This allows the
system more flexibility when assigning SKB hash space to next hops.
Previously, each next hop had to be assigned a continuous range of SKB hash
space. With a hash table as an intermediate layer, it is possible to
reassign next hops with a hash table bucket granularity. In turn, this
mends issues with traffic flow redirection resulting from next hop removal
or adjustments in next-hop weights.

This patch set introduces mock offloading of resilient next hop groups by
the netdevsim driver, and a suite of selftests.

- Patch #1 adds a netdevsim-specific lock to protect next-hop hashtable.
  Previously, netdevsim relied on RTNL to maintain mutual exclusion.
  Patch #2 extracts a helper to make the following patches clearer.

- Patch #3 implements the support for offloading of resilient next-hop
  groups.

- Patch #4 introduces a new debugfs interface to set activity on a selected
  next-hop bucket. This simulates how HW can periodically report bucket
  activity, and buckets thus marked are expected to be exempt from
  migration to new next hops when the group changes.

- Patches #5 and #6 clean up the fib_nexthop selftests.

- Patches #7, #8 and #9 add tests for resilient next hop groups. Patch #7
  adds resilient-hashing counterparts to fib_nexthops.sh. Patch #8 adds a
  new traffic test for resilient next-hop groups. Patch #9 adds a new
  traffic test for tunneling.

- Patch #10 actually leverages the netdevsim offload to implement a suite
  of algorithmic tests that verify how and when buckets are migrated under
  various simulated workload scenarios.

The overall plan is to contribute approximately the following patchsets:

1) Nexthop policy refactoring (already pushed)
2) Preparations for resilient next hop groups (already pushed)
3) Implementation of resilient next hop group (already pushed)
4) Netdevsim offload plus a suite of selftests (this patchset)
5) Preparations for mlxsw offload of resilient next-hop groups
6) mlxsw offload including selftests

Interested parties can look at the complete code at [2].

[1] https://tools.ietf.org/html/rfc2992
[2] https://github.com/idosch/linux/commits/submit/res_integ_v1
====================

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