perf: Add context field to perf_event

The perf_event overflow handler does not receive any caller-derived
argument, so many callers need to resort to looking up the perf_event
in their local data structure.  This is ugly and doesn't scale if a
single callback services many perf_events.

Fix by adding a context parameter to perf_event_create_kernel_counter()
(and derived hardware breakpoints APIs) and storing it in the perf_event.
The field can be accessed from the callback as event->overflow_handler_context.
All callers are updated.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1309362157-6596-2-git-send-email-avi@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/oprofile/oprofile_perf.c b/drivers/oprofile/oprofile_perf.c
index 9046f7b2ed79..59acf9ef78a4 100644
--- a/drivers/oprofile/oprofile_perf.c
+++ b/drivers/oprofile/oprofile_perf.c
@@ -79,7 +79,7 @@ static int op_create_counter(int cpu, int event)
 
         pevent = perf_event_create_kernel_counter(&counter_config[event].attr,
                                                   cpu, NULL,
-                                                  op_overflow_handler);
+                                                  op_overflow_handler, NULL);
 
         if (IS_ERR(pevent))
                 return PTR_ERR(pevent);