net: sched: run ingress qdisc without locks

net: sched: run ingress qdisc without locks

TC classifiers/actions were converted to RCU by John in the series:
http://thread.gmane.org/gmane.linux.network/329739/focus=329739
and many follow on patches.
This is the last patch from that series that finally drops
ingress spin_lock.

Single cpu ingress+u32 performance goes from 22.9 Mpps to 24.5 Mpps.

In two cpu case when both cores are receiving traffic on the same
device and go into the same ingress+u32 the performance jumps
from 4.5 + 4.5 Mpps to 23.5 + 23.5 Mpps

Signed-off-by: John Fastabend <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Signed-off-by: Jamal Hadi Salim <[email protected]>
Acked-by: Daniel Borkmann <[email protected]>
Signed-off-by: David S. Miller <[email protected]>