Put the recursion avoidance code in the generic hook instead of
replicating it in each implementation.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
LKML-Reference: <20100127221122.057507285@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>