[PATCH 2/4] tracepoints: Move struct tracepoint to new tracepoint-defs.h header

[Andi Kleen]

From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

Steven recommended open coding access to tracepoint->key to add
trace points to headers. Unfortunately this is difficult for some
headers (such as x86 asm/msr.h) because including tracepoint.h
includes so many other headers that it causes include loops.
The main problem is the include of linux/rcupdate.h, which
pulls in a lot of other headers. The rcu header is only needed
when actually defining trace points.

Move the struct tracepoint into a separate tracepoint-defs.h
header that can be included without pulling in all of RCU.

Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
 include/linux/tracepoint-defs.h | 26 ++++++++++++++++++++++++++
 include/linux/tracepoint.h      | 15 +--------------
 2 files changed, 27 insertions(+), 14 deletions(-)
 create mode 100644 include/linux/tracepoint-defs.h

diff --git a/include/linux/tracepoint-defs.h b/include/linux/tracepoint-defs.h
new file mode 100644
index 0000000..881aa6b
--- /dev/null
+++ b/include/linux/tracepoint-defs.h
@@ -0,0 +1,26 @@
+#ifndef TRACEPOINT_DEFS_H
+#define TRACEPOINT_DEFS_H 1
+
+/*
+ * File can be included directly by headers who only want to access
+ * tracepoint->key to guard out of line trace calls. Otherwise
+ * linux/tracepoint.h should be used.
+ */
+
+#include <linux/atomic.h>
+#include <linux/static_key.h>
+
+struct tracepoint_func {
+	void *func;
+	void *data;
+};
+
+struct tracepoint {
+	const char *name;		/* Tracepoint name */
+	struct static_key key;
+	void (*regfunc)(void);
+	void (*unregfunc)(void);
+	struct tracepoint_func __rcu *funcs;
+};
+
+#endif
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index a5f7f3e..71072d1 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -17,25 +17,12 @@
 #include <linux/errno.h>
 #include <linux/types.h>
 #include <linux/rcupdate.h>
-#include <linux/static_key.h>
+#include <linux/tracepoint-defs.h>
 
 struct module;
 struct tracepoint;
 struct notifier_block;
 
-struct tracepoint_func {
-	void *func;
-	void *data;
-};
-
-struct tracepoint {
-	const char *name;		/* Tracepoint name */
-	struct static_key key;
-	void (*regfunc)(void);
-	void (*unregfunc)(void);
-	struct tracepoint_func __rcu *funcs;
-};
-
 struct trace_enum_map {
 	const char		*system;
 	const char		*enum_string;
-- 
2.4.3

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