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(-)
