While debugging a warning message on PowerPC while using hardware
breakpoints, it was discovered that when perf_event_disable is invoked
through hw_breakpoint_handler function with interrupts disabled, a
subsequent IPI in the code path would trigger a WARN_ON_ONCE message in
smp_call_function_single function.

This patch calls __perf_event_disable() when interrupts are already
disabled, instead of perf_event_disable().
Reported-by: NEdjunior Barbosa Machado <emachado@linux.vnet.ibm.com>
Signed-off-by: NK.Prasad <Prasad.Krishnan@gmail.com>
[naveen.n.rao@linux.vnet.ibm.com: v3: Check to make sure we target current task]
Signed-off-by: NNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: NFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120802081635.5811.17737.stgit@localhost.localdomain
[ Fixed build error on MIPS. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>