[PATCH 17/32] perf/core: adding pmu::event_terminate

[David Carrillo-Cisneros]

Allow a PMU to clean an event before the event's torn down in
perf_events begins.

Reviewed-by: Stephane Eranian <eran...@google.com>
Signed-off-by: David Carrillo-Cisneros <davi...@google.com>
---
 include/linux/perf_event.h | 6 ++++++
 kernel/events/core.c       | 4 ++++
 2 files changed, 10 insertions(+)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index b010b55..81e29c6 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -265,6 +265,12 @@ struct pmu {
        int (*event_init)               (struct perf_event *event);
 
        /*
+        * Terminate the event for this PMU. Optional complement for a
+        * successful event_init. Called before the event fields are tear down.
+        */
+       void (*event_terminate)         (struct perf_event *event);
+
+       /*
         * Notification that the event was mapped or unmapped.  Called
         * in the context of the mapping task.
         */
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 6fd226f..2a868a6 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3787,6 +3787,8 @@ static void _free_event(struct perf_event *event)
                ring_buffer_attach(event, NULL);
                mutex_unlock(&event->mmap_mutex);
        }
+       if (event->pmu->event_terminate)
+               event->pmu->event_terminate(event);
 
        if (is_cgroup_event(event))
                perf_detach_cgroup(event);
@@ -8293,6 +8295,8 @@ err_per_task:
        exclusive_event_destroy(event);
 
 err_pmu:
+       if (event->pmu->event_terminate)
+               event->pmu->event_terminate(event);
        if (event->destroy)
                event->destroy(event);
        module_put(pmu->module);
-- 
2.8.0.rc3.226.g39d4020