From 1744a21d57d9c60136461adb6afa85e51b3e94d9 Mon Sep 17 00:00:00 2001
From: Vegard Nossum <vegard.nossum@gmail.com>
Date: Sat, 28 Feb 2009 08:29:44 +0100
Subject: trace: annotate bitfields in struct ring_buffer_event

This gets rid of a heap of false-positive warnings from the tracer
code due to the use of bitfields.

[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
---
 include/linux/ring_buffer.h | 4 ++++
 kernel/trace/ring_buffer.c  | 3 +++
 2 files changed, 7 insertions(+)

diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index 8670f1575fe1..29f8599e6bea 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -1,6 +1,7 @@
 #ifndef _LINUX_RING_BUFFER_H
 #define _LINUX_RING_BUFFER_H
 
+#include <linux/kmemcheck.h>
 #include <linux/mm.h>
 #include <linux/seq_file.h>
 
@@ -11,7 +12,10 @@ struct ring_buffer_iter;
  * Don't refer to this struct directly, use functions below.
  */
 struct ring_buffer_event {
+	kmemcheck_bitfield_begin(bitfield);
 	u32		type_len:5, time_delta:27;
+	kmemcheck_bitfield_end(bitfield);
+
 	u32		array[];
 };
 
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 2e642b2b7253..dc4dc70171ce 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -10,6 +10,7 @@
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/hardirq.h>
+#include <linux/kmemcheck.h>
 #include <linux/module.h>
 #include <linux/percpu.h>
 #include <linux/mutex.h>
@@ -1270,6 +1271,7 @@ rb_move_tail(struct ring_buffer_per_cpu *cpu_buffer,
 	if (tail < BUF_PAGE_SIZE) {
 		/* Mark the rest of the page with padding */
 		event = __rb_page_index(tail_page, tail);
+		kmemcheck_annotate_bitfield(event, bitfield);
 		rb_event_set_padding(event);
 	}
 
@@ -1327,6 +1329,7 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
 		return NULL;
 
 	event = __rb_page_index(tail_page, tail);
+	kmemcheck_annotate_bitfield(event, bitfield);
 	rb_update_event(event, type, length);
 
 	/* The passed in type is zero for DATA */
-- 
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