ftrace: Remove data field from ftrace_func_probe structure

No users of the function probes uses the data field anymore. Remove it, and
change the init function to take a void *data parameter instead of a
void **data, because the init will just get the data that the registering
function was received, and there's no state after it is called.

The other functions for ftrace_probe_ops still take the data parameter, but
it will currently only be passed NULL. It will stay as a parameter for
future data to be passed to these functions.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

kernel/trace/ftrace.c

@@ -1102,7 +1102,6 @@ struct ftrace_func_probe {
 	struct hlist_node	node;
 	struct ftrace_probe_ops	*ops;
 	unsigned long		ip;
-	void			*data;
 	struct list_head	free_list;
 };
 
@@ -3152,7 +3151,7 @@ t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
 		return -EIO;
 
 	if (rec->ops->print)
-		return rec->ops->print(m, rec->ip, rec->ops, rec->data);
+		return rec->ops->print(m, rec->ip, rec->ops, NULL);
 
 	seq_printf(m, "%ps:%ps\n", (void *)rec->ip, (void *)rec->ops->func);
 
@@ -3735,7 +3734,7 @@ static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
 	preempt_disable_notrace();
 	hlist_for_each_entry_rcu_notrace(entry, hhd, node) {
 		if (entry->ip == ip)
-			entry->ops->func(ip, parent_ip, entry->ops, &entry->data);
+			entry->ops->func(ip, parent_ip, entry->ops, NULL);
 	}
 	preempt_enable_notrace();
 }
@@ -3800,7 +3799,7 @@ static bool __disable_ftrace_function_probe(void)
 static void ftrace_free_entry(struct ftrace_func_probe *entry)
 {
 	if (entry->ops->free)
-		entry->ops->free(entry->ops, entry->ip, &entry->data);
+		entry->ops->free(entry->ops, entry->ip, NULL);
 	kfree(entry);
 }
 
@@ -4007,15 +4006,13 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 
 		count++;
 
-		entry->data = data;
-
 		/*
 		 * The caller might want to do something special
 		 * for each function we find. We call the callback
 		 * to give the caller an opportunity to do so.
 		 */
 		if (ops->init) {
-			if (ops->init(ops, rec->ip, &entry->data) < 0) {
+			if (ops->init(ops, rec->ip, data) < 0) {
 				/* caller does not like this func */
 				kfree(entry);
 				continue;

kernel/trace/trace.c

@@ -6786,11 +6786,11 @@ ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
 
 static int
 ftrace_snapshot_init(struct ftrace_probe_ops *ops, unsigned long ip,
-		     void **data)
+		     void *data)
 {
 	struct ftrace_func_mapper *mapper = ops->private_data;
 
-	return ftrace_func_mapper_add_ip(mapper, ip, *data);
+	return ftrace_func_mapper_add_ip(mapper, ip, data);
 }
 
 static void

kernel/trace/trace.h

@@ -937,7 +937,7 @@ struct ftrace_probe_ops {
 					struct ftrace_probe_ops *ops,
 					void **data);
 	int			(*init)(struct ftrace_probe_ops *ops,
-					unsigned long ip, void **data);
+					unsigned long ip, void *data);
 	void			(*free)(struct ftrace_probe_ops *ops,
 					unsigned long ip, void **data);
 	int			(*print)(struct seq_file *m,

kernel/trace/trace_events.c

@@ -2543,11 +2543,10 @@ event_enable_print(struct seq_file *m, unsigned long ip,
 
 static int
 event_enable_init(struct ftrace_probe_ops *ops, unsigned long ip,
-		  void **_data)
+		  void *_data)
 {
 	struct ftrace_func_mapper *mapper = ops->private_data;
-	struct event_probe_data **pdata = (struct event_probe_data **)_data;
-	struct event_probe_data *data = *pdata;
+	struct event_probe_data *data = _data;
 	int ret;
 
 	ret = ftrace_func_mapper_add_ip(mapper, ip, data);

kernel/trace/trace_functions.c

@@ -509,11 +509,11 @@ ftrace_cpudump_print(struct seq_file *m, unsigned long ip,
 
 static int
 ftrace_count_init(struct ftrace_probe_ops *ops, unsigned long ip,
-		     void **data)
+		     void *data)
 {
 	struct ftrace_func_mapper *mapper = ops->private_data;
 
-	return ftrace_func_mapper_add_ip(mapper, ip, *data);
+	return ftrace_func_mapper_add_ip(mapper, ip, data);
 }
 
 static void