Merge remote-tracking branch 'hid/for-next'

[karo-tx-linux.git] / include / linux / perf_event.h

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 866e85c5eb94517fc87ca1d49bc9acbde74dcc74..c8ba627c1d608733b8480bb929d9e81d97e57fa0 100644 (file)
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -294,9 +294,31 @@ struct ring_buffer;
  */
 struct perf_event {
 #ifdef CONFIG_PERF_EVENTS
-       struct list_head                group_entry;
+       /*
+        * entry onto perf_event_context::event_list;
+        *   modifications require ctx->lock
+        *   RCU safe iterations.
+        */
        struct list_head                event_entry;
+
+       /*
+        * XXX: group_entry and sibling_list should be mutually exclusive;
+        * either you're a sibling on a group, or you're the group leader.
+        * Rework the code to always use the same list element.
+        *
+        * Locked for modification by both ctx->mutex and ctx->lock; holding
+        * either sufficies for read.
+        */
+       struct list_head                group_entry;
        struct list_head                sibling_list;
+
+       /*
+        * We need storage to track the entries in perf_pmu_migrate_context; we
+        * cannot use the event_entry because of RCU and we want to keep the
+        * group in tact which avoids us using the other two entries.
+        */
+       struct list_head                migrate_entry;
+
        struct hlist_node               hlist_entry;
        int                             nr_siblings;
        int                             group_flags;