tracing/ftrace: provide the macro task_curr_ret_stack()

Impact: cleanup

As suggested by Steven Rostedt, this patch provide a new macro
task_curr_ret_stack() to move the cpp conditionnal CONFIG into
the linux/ftrace.h headers.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/linux/ftrace.h

@@ -8,6 +8,7 @@
 #include <linux/types.h>
 #include <linux/kallsyms.h>
 #include <linux/bitops.h>
+#include <linux/sched.h>
 
 #ifdef CONFIG_FUNCTION_TRACER
 
@@ -387,9 +388,19 @@ extern void unregister_ftrace_graph(void);
 
 extern void ftrace_graph_init_task(struct task_struct *t);
 extern void ftrace_graph_exit_task(struct task_struct *t);
+
+static inline int task_curr_ret_stack(struct task_struct *t)
+{
+	return t->curr_ret_stack;
+}
 #else
 static inline void ftrace_graph_init_task(struct task_struct *t) { }
 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
+
+static inline int task_curr_ret_stack(struct task_struct *tsk)
+{
+	return -1;
+}
 #endif
 
 #ifdef CONFIG_TRACING

kernel/trace/trace.c

@@ -3657,13 +3657,7 @@ int __ftrace_printk(unsigned long ip, const char *fmt, ...)
 		return 0;
 
 	va_start(ap, fmt);
-
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	ret = trace_vprintk(ip, current->curr_ret_stack, fmt, ap);
-#else
-	ret = trace_vprintk(ip, -1, fmt, ap);
-#endif
-
+	ret = trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
 	va_end(ap);
 	return ret;
 }