[PATCH] perf_event.h: Add RCU Annotation to struct ring_buffer in perf_event

[madhuparnabhowmik10]

From: Madhuparna Bhowmik <madhuparnabhowmik10@xxxxxxxxx>

This patch fixes the following sparse errors in events/core.c
and events/ring_buffer.c by adding RCU Annotation to struct
ring_buffer in perf_event:

kernel/events/core.c:5597:9: error: incompatible types in comparison expression
kernel/events/core.c:5303:22: error: incompatible types in comparison expression
kernel/events/core.c:5439:14: error: incompatible types in comparison expression
kernel/events/core.c:5472:14: error: incompatible types in comparison expression
kernel/events/core.c:5529:14: error: incompatible types in comparison expression
kernel/events/core.c:5615:14: error: incompatible types in comparison expression
kernel/events/core.c:5615:14: error: incompatible types in comparison expression
kernel/events/core.c:7183:13: error: incompatible types in comparison expression

kernel/events/ring_buffer.c:169:14: error: incompatible types in comparison expression

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@xxxxxxxxx>
---
 include/linux/perf_event.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 6d4c22aee384..1691107d2800 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -694,7 +694,7 @@ struct perf_event {
 	struct mutex			mmap_mutex;
 	atomic_t			mmap_count;
 
-	struct ring_buffer		*rb;
+	struct ring_buffer __rcu	*rb;
 	struct list_head		rb_entry;
 	unsigned long			rcu_batches;
 	int				rcu_pending;
-- 
2.17.1