ftrace: Have set_ftrace_pid use the bitmap like events do

Convert set_ftrace_pid to use the bitmap like set_event_pid does. This
allows for instances to use the pid filtering as well, and will allow for
function-fork option to set if the children of a traced function should be
traced or not.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace.c

@@ -7233,6 +7233,7 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
 	for_each_tracing_cpu(cpu)
 		tracing_init_tracefs_percpu(tr, cpu);
 
+	ftrace_init_tracefs(tr, d_tracer);
 }
 
 static struct vfsmount *trace_automount(void *ingore)

kernel/trace/trace.h

@@ -156,6 +156,9 @@ struct trace_array_cpu {
 	char			comm[TASK_COMM_LEN];
 
 	bool			ignore_pid;
+#ifdef CONFIG_FUNCTION_TRACER
+	bool			ftrace_ignore_pid;
+#endif
 };
 
 struct tracer;
@@ -247,6 +250,7 @@ struct trace_array {
 	int			ref;
 #ifdef CONFIG_FUNCTION_TRACER
 	struct ftrace_ops	*ops;
+	struct trace_pid_list	__rcu *function_pids;
 	/* function tracing enabled */
 	int			function_enabled;
 #endif
@@ -840,12 +844,9 @@ extern struct list_head ftrace_pids;
 
 #ifdef CONFIG_FUNCTION_TRACER
 extern bool ftrace_filter_param __initdata;
-static inline int ftrace_trace_task(struct task_struct *task)
+static inline int ftrace_trace_task(struct trace_array *tr)
 {
-	if (list_empty(&ftrace_pids))
-		return 1;
-
-	return test_tsk_trace_trace(task);
+	return !this_cpu_read(tr->trace_buffer.data->ftrace_ignore_pid);
 }
 extern int ftrace_is_dead(void);
 int ftrace_create_function_files(struct trace_array *tr,
@@ -855,8 +856,9 @@ void ftrace_init_global_array_ops(struct trace_array *tr);
 void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func);
 void ftrace_reset_array_ops(struct trace_array *tr);
 int using_ftrace_ops_list_func(void);
+void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer);
 #else
-static inline int ftrace_trace_task(struct task_struct *task)
+static inline int ftrace_trace_task(struct trace_array *tr)
 {
 	return 1;
 }
@@ -871,6 +873,7 @@ static inline void ftrace_destroy_function_files(struct trace_array *tr) { }
 static inline __init void
 ftrace_init_global_array_ops(struct trace_array *tr) { }
 static inline void ftrace_reset_array_ops(struct trace_array *tr) { }
+static inline void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d) { }
 /* ftace_func_t type is not defined, use macro instead of static inline */
 #define ftrace_init_array_ops(tr, func) do { } while (0)
 #endif /* CONFIG_FUNCTION_TRACER */

kernel/trace/trace_functions.c

@@ -43,7 +43,7 @@ static int allocate_ftrace_ops(struct trace_array *tr)
 
 	/* Currently only the non stack verision is supported */
 	ops->func = function_trace_call;
-	ops->flags = FTRACE_OPS_FL_RECURSION_SAFE;
+	ops->flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_PID;
 
 	tr->ops = ops;
 	ops->private = tr;

kernel/trace/trace_functions_graph.c

@@ -319,7 +319,7 @@ int trace_graph_entry(struct ftrace_graph_ent *trace)
 	int cpu;
 	int pc;
 
-	if (!ftrace_trace_task(current))
+	if (!ftrace_trace_task(tr))
 		return 0;
 
 	/* trace it when it is-nested-in or is a function enabled. */