ftrace: Dynamically create the probe ftrace_ops for the trace_array

In order to eventually have each trace_array instance have its own unique
set of function probes (triggers), the trace array needs to hold the ops and
the filters for the probes.

This is the first step to accomplish this. Instead of having the private
data of the probe ops point to the trace_array, create a separate list that
the trace_array holds. There's only one private_data for a probe, we need
one per trace_array. The probe ftrace_ops will be dynamically created for
each instance, instead of being static.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

kernel/trace/trace.c

@@ -6832,7 +6832,7 @@ ftrace_trace_snapshot_callback(struct trace_array *tr, struct ftrace_hash *hash,
 	ops = param ? &snapshot_count_probe_ops :  &snapshot_probe_ops;
 
 	if (glob[0] == '!')
-		return unregister_ftrace_function_probe_func(glob+1, ops);
+		return unregister_ftrace_function_probe_func(glob+1, tr, ops);
 
 	if (!param)
 		goto out_reg;

kernel/trace/trace.h

@@ -939,8 +939,6 @@ static inline void ftrace_pid_follow_fork(struct trace_array *tr, bool enable) {
 #if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_DYNAMIC_FTRACE)
 
 struct ftrace_probe_ops {
-	struct ftrace_ops	ops;
-	struct list_head	list;
 	void			(*func)(unsigned long ip,
 					unsigned long parent_ip,
 					struct trace_array *tr,
@@ -976,7 +974,8 @@ extern int
 register_ftrace_function_probe(char *glob, struct trace_array *tr,
 			       struct ftrace_probe_ops *ops, void *data);
 extern int
-unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops);
+unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
+				      struct ftrace_probe_ops *ops);
 
 int register_ftrace_command(struct ftrace_func_command *cmd);
 int unregister_ftrace_command(struct ftrace_func_command *cmd);

kernel/trace/trace_events.c

@@ -2653,7 +2653,7 @@ event_enable_func(struct trace_array *tr, struct ftrace_hash *hash,
 		ops = param ? &event_disable_count_probe_ops : &event_disable_probe_ops;
 
 	if (glob[0] == '!') {
-		ret = unregister_ftrace_function_probe_func(glob+1, ops);
+		ret = unregister_ftrace_function_probe_func(glob+1, tr, ops);
 		goto out;
 	}
 

kernel/trace/trace_functions.c

@@ -597,7 +597,7 @@ ftrace_trace_probe_callback(struct trace_array *tr,
 		return -EINVAL;
 
 	if (glob[0] == '!')
-		return unregister_ftrace_function_probe_func(glob+1, ops);
+		return unregister_ftrace_function_probe_func(glob+1, tr, ops);
 
 	if (!param)
 		goto out_reg;