perf: Pass last sampling period to perf_sample_data_init()

We always need to pass the last sample period to
perf_sample_data_init(), otherwise the event distribution will be
wrong. Thus, modifiyng the function interface with the required period
as argument. So basically a pattern like this:

        perf_sample_data_init(&data, ~0ULL);
        data.period = event->hw.last_period;

will now be like that:

        perf_sample_data_init(&data, ~0ULL, event->hw.last_period);

Avoids unininitialized data.period and simplifies code.

Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1333390758-10893-3-git-send-email-robert.richter@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index ddbb6a901f65..f32578634d9d 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1132,11 +1132,14 @@ struct perf_sample_data {
         struct perf_branch_stack        *br_stack;
 };
 
-static inline void perf_sample_data_init(struct perf_sample_data *data, u64 addr)
+static inline void perf_sample_data_init(struct perf_sample_data *data,
+                                         u64 addr, u64 period)
 {
+        /* remaining struct members initialized in perf_prepare_sample() */
         data->addr = addr;
         data->raw  = NULL;
         data->br_stack = NULL;
+        data->period    = period;
 }
 
 extern void perf_output_sample(struct perf_output_handle *handle,