tracepoints: Move struct tracepoint to new tracepoint-defs.h header

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@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1449018060-1742-2-git-send-email-andi@firstfloor.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

include/linux/tracepoint-defs.h

+#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;
+	int prio;
+};
+
+struct tracepoint {
+	const char *name;		/* Tracepoint name */
+	struct static_key key;
+	void (*regfunc)(void);
+	void (*unregfunc)(void);
+	struct tracepoint_func __rcu *funcs;
+};
+
+#endif

include/linux/tracepoint.h

@@ -17,26 +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;
-	int prio;
-};
-
-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;