xfrm: policy: make xfrm_policy_lookup_bytype lockless

side effect: no longer disables BH (should be fine).

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 09f2e2b..9302647 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1123,7 +1123,7 @@
 	if (unlikely(!daddr || !saddr))
 		return NULL;
 
-	read_lock_bh(&net->xfrm.xfrm_policy_lock);
+	rcu_read_lock();
  retry:
 	do {
 		sequence = read_seqcount_begin(&xfrm_policy_hash_generation);
@@ -1172,7 +1172,7 @@
 	if (ret && !xfrm_pol_hold_rcu(ret))
 		goto retry;
 fail:
-	read_unlock_bh(&net->xfrm.xfrm_policy_lock);
+	rcu_read_unlock();
 
 	return ret;
 }