ftrace: fix up cmdline recording

The new work with converting the trace hooks over to markers broke the
command line recording of ftrace. This patch fixes it again.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/trace/trace.c

@@ -652,9 +652,6 @@ static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
 static int cmdline_idx;
 static DEFINE_SPINLOCK(trace_cmdline_lock);
 
-/* trace in all context switches */
-atomic_t trace_record_cmdline_enabled __read_mostly;
-
 /* temporary disable recording */
 atomic_t trace_record_cmdline_disabled __read_mostly;
 

kernel/trace/trace.h

@@ -218,6 +218,8 @@ void trace_function(struct trace_array *tr,
 
 void tracing_start_function_trace(void);
 void tracing_stop_function_trace(void);
+void tracing_start_cmdline_record(void);
+void tracing_stop_cmdline_record(void);
 int register_tracer(struct tracer *type);
 void unregister_tracer(struct tracer *type);
 
@@ -226,8 +228,6 @@ extern unsigned long nsecs_to_usecs(unsigned long nsecs);
 extern unsigned long tracing_max_latency;
 extern unsigned long tracing_thresh;
 
-extern atomic_t trace_record_cmdline_enabled;
-
 void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu);
 void update_max_tr_single(struct trace_array *tr,
 			  struct task_struct *tsk, int cpu);

kernel/trace/trace_functions.c

@@ -29,14 +29,14 @@ static void function_reset(struct trace_array *tr)
 static void start_function_trace(struct trace_array *tr)
 {
 	function_reset(tr);
-	atomic_inc(&trace_record_cmdline_enabled);
+	tracing_start_cmdline_record();
 	tracing_start_function_trace();
 }
 
 static void stop_function_trace(struct trace_array *tr)
 {
 	tracing_stop_function_trace();
-	atomic_dec(&trace_record_cmdline_enabled);
+	tracing_stop_cmdline_record();
 }
 
 static void function_trace_init(struct trace_array *tr)

kernel/trace/trace_sched_switch.c

@@ -29,6 +29,9 @@ sched_switch_func(void *private, void *__rq, struct task_struct *prev,
 	long disabled;
 	int cpu;
 
+	tracing_record_cmdline(prev);
+	tracing_record_cmdline(next);
+
 	if (!tracer_enabled)
 		return;
 
@@ -63,8 +66,6 @@ sched_switch_callback(void *probe_data, void *call_data,
 	prev = va_arg(*args, typeof(prev));
 	next = va_arg(*args, typeof(next));
 
-	tracing_record_cmdline(prev);
-
 	/*
 	 * If tracer_switch_func only points to the local
 	 * switch func, it still needs the ptr passed to it.
@@ -213,18 +214,26 @@ void tracing_stop_sched_switch(void)
 		tracing_sched_unregister();
 }
 
+void tracing_start_cmdline_record(void)
+{
+	tracing_start_sched_switch();
+}
+
+void tracing_stop_cmdline_record(void)
+{
+	tracing_stop_sched_switch();
+}
+
 static void start_sched_trace(struct trace_array *tr)
 {
 	sched_switch_reset(tr);
-	atomic_inc(&trace_record_cmdline_enabled);
 	tracer_enabled = 1;
-	tracing_start_sched_switch();
+	tracing_start_cmdline_record();
 }
 
 static void stop_sched_trace(struct trace_array *tr)
 {
-	tracing_stop_sched_switch();
-	atomic_dec(&trace_record_cmdline_enabled);
+	tracing_stop_cmdline_record();
 	tracer_enabled = 0;
 }