Subject: [PATCH ipsec-next 0/8] xfrm: policy: convert lookups to rcu

[Florian Westphal <fw@strlen.de>]

Since commit d188ba86dd07a72eb ("xfrm: add rcu protection to sk->sk_policy[]")
sk_policy can rely on rcu protection.

This change allows to also use rcu in xfrm_policy_lookup_bytype and to
avoid grabbing the read-sie policy lock during lookups.

read-side policy rwlock is converted to pure rcu, then the policy_lock is
changed to a plain spinlock as only write-sides remain.

First few patches do some preparation work, the later ones remove
the read-side locks, last patch converts rwlock to spinlock.

I tested this with rcu debug enabled and simple esp tunnel
forwarding udp packets.

If you have better tests for this please let me know and I can re-run with
that.

Florian Westphal (8):
      xfrm: policy: use rcu versions for iteration and list add/del
      xfrm: policy: prepare policy_bydst hash for rcu lookups
      xfrm: policy: add sequence count to synchronize reads with hash resizes
      xfrm: policy: use atomic_inc_not_zero in rcu section
      xfrm: policy: make xfrm_policy_lookup_bytype lockless
      xfrm: policy: only use rcu in xfrm_sk_policy_lookup
      xfrm: policy: don't acquire policy lock in xfrm_spd_getinfo
      xfrm: policy: convert policy_lock to spinlock

 include/net/netns/xfrm.h |    4 -
 net/xfrm/xfrm_policy.c   |  145 +++++++++++++++++++++++++++--------------------
 2 files changed, 88 insertions(+), 61 deletions(-)