xfrm: Namespacify xfrm state/policy locks
By semantics, xfrm layer is fully name space aware, so will the locks, e.g. xfrm_state/pocliy_lock. Ensure exclusive access into state/policy link list for different name space with one global lock is not right in terms of semantics aspect at first place, as they are indeed mutually independent with each other, but also more seriously causes scalability problem. One practical scenario is on a Open Network Stack, more than hundreds of lxc tenants acts as routers within one host, a global xfrm_state/policy_lock becomes the bottleneck. But onces those locks are decoupled in a per-namespace fashion, locks contend is just with in specific name space scope, without causing additional SPD/SAD access delay for other name space. Also this patch improve scalability while as without changing original xfrm behavior. Signed-off-by: Fan Du <fan.du@windriver.com> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>