ring_buffer: ring_buffer_empty{cpu}() can return boolean

Make ring_buffer_empty() and ring_buffer_empty_cpu() return bool.

No functional change.

Link: http://lkml.kernel.org/r/1443537816-5788-5-git-send-email-bywxiaobai@163.com

Signed-off-by: Yaowei Bai <bywxiaobai@163.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index e2c13cd..4acc552 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -154,8 +154,8 @@
 }
 #endif
 
-int ring_buffer_empty(struct ring_buffer *buffer);
-int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu);
+bool ring_buffer_empty(struct ring_buffer *buffer);
+bool ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu);
 
 void ring_buffer_record_disable(struct ring_buffer *buffer);
 void ring_buffer_record_enable(struct ring_buffer *buffer);