TC: refactor TC_ACT_REDIRECT action

This series is aimed at improving the act_mirred redirect performances. Such action is used by OVS to represent TC S/W flows, and it's current largest bottle-neck is the need for a skb_clone() for each packet.

The first 2 patches introduce some cleanup and safeguards to allow changing the TC_ACT_REDIRECT handling: currently the action context is stored in per CPU variables, and we allow also to use the tcf_result. Finally we use this extended infrastructure in act_mirred to implement redirect via TC_ACT_REDIRECT, when possible.

Overall this the above gives a ~10% performance improvement in forwarding tput, when using the TC S/W datapath.

Paolo Abeni (4):
tc/act: user space can't use TC_ACT_REDIRECT directly tc/act: remove unneeded RCU lock in action callback net/sched: refactor TC_ACT_REDIRECT handling
act_mirred: use ACT_REDIRECT when possible

 include/net/act_api.h        |  2 +-
 include/net/sch_generic.h    | 17 ++++++++++++++++-
 include/uapi/linux/pkt_cls.h |  1 +
 net/core/dev.c               |  4 ++--
 net/core/filter.c            | 29 +++++++++++++++++++++++------
 net/core/lwt_bpf.c           |  5 ++++-
 net/sched/act_api.c          |  5 +++++
 net/sched/act_bpf.c          |  8 ++++----
 net/sched/act_csum.c         | 12 +++---------
 net/sched/act_ife.c          |  5 +----
 net/sched/act_mirred.c       | 19 ++++++++++++++-----
 net/sched/act_sample.c       |  4 +---
 net/sched/act_skbedit.c      | 10 +++-------
 net/sched/act_skbmod.c       | 21 +++++++++------------
 net/sched/act_tunnel_key.c   |  6 +-----
 net/sched/act_vlan.c         | 19 +++++++------------
 net/sched/cls_bpf.c          |  8 +++++---
 17 files changed, 100 insertions(+), 75 deletions(-)

2.17.1