[PATCH ipsec-next 0/6] xfrm: remove xfrm_state_get_afinfo conditional rcu locking

[Florian Westphal <fw@strlen.de>]

xfrm_state_get_afinfo still uses a conditional locking scheme
dating back to when this still used an rwlock:

If return value is NULL, no lock (rcu readlock) was taken,
otherwise, rcu_read_unlock has to be called.

This series moves rcu read lock/unlock responsibility to the callers.

xfrm_state_put_afinfo is removed (it is equivalent
to rcu_read_unlock so thats what will be used instead).

xfrm_state_get_afinfo is renamed to xfrm_state_afinfo_get_rcu()
and is only a rcu dereference wrapper.

In one case, rcu read/unlock can be avoided as we're always
called with rcu read lock held.