hw_breakpoint: Simplify *register_wide_hw_breakpoint()
1. register_wide_hw_breakpoint() can use unregister_ if failure,
no need to duplicate the code.
2. "struct perf_event **pevent" adds the unnecesary lever of
indirection and complication, use per_cpu(*cpu_events, cpu).
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20130620155018.GA6347@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
index 9c71445..38418f7 100644
--- a/kernel/events/hw_breakpoint.c
+++ b/kernel/events/hw_breakpoint.c
@@ -497,8 +497,8 @@
perf_overflow_handler_t triggered,
void *context)
{
- struct perf_event * __percpu *cpu_events, **pevent, *bp;
- long err;
+ struct perf_event * __percpu *cpu_events, *bp;
+ long err = 0;
int cpu;
cpu_events = alloc_percpu(typeof(*cpu_events));
@@ -507,31 +507,21 @@
get_online_cpus();
for_each_online_cpu(cpu) {
- pevent = per_cpu_ptr(cpu_events, cpu);
bp = perf_event_create_kernel_counter(attr, cpu, NULL,
triggered, context);
-
- *pevent = bp;
-
if (IS_ERR(bp)) {
err = PTR_ERR(bp);
- goto fail;
- }
- }
- put_online_cpus();
-
- return cpu_events;
-
-fail:
- for_each_online_cpu(cpu) {
- pevent = per_cpu_ptr(cpu_events, cpu);
- if (IS_ERR(*pevent))
break;
- unregister_hw_breakpoint(*pevent);
+ }
+
+ per_cpu(*cpu_events, cpu) = bp;
}
put_online_cpus();
- free_percpu(cpu_events);
+ if (likely(!err))
+ return cpu_events;
+
+ unregister_wide_hw_breakpoint(cpu_events);
return (void __percpu __force *)ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(register_wide_hw_breakpoint);
@@ -543,12 +533,10 @@
void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events)
{
int cpu;
- struct perf_event **pevent;
- for_each_possible_cpu(cpu) {
- pevent = per_cpu_ptr(cpu_events, cpu);
- unregister_hw_breakpoint(*pevent);
- }
+ for_each_possible_cpu(cpu)
+ unregister_hw_breakpoint(per_cpu(*cpu_events, cpu));
+
free_percpu(cpu_events);
}
EXPORT_SYMBOL_GPL(unregister_wide_hw_breakpoint);