tracing/probe: Add trace_event_call accesses APIs

Add trace_event_call access APIs for trace_probe.
Instead of accessing trace_probe.call directly, use those
accesses by trace_probe_event_call() method. This hides
the relationship of trace_event_call and trace_probe from
trace_kprobe and trace_uprobe.

Link: http://lkml.kernel.org/r/155931587711.28323.8335129014686133120.stgit@devnote2

Signed-off-by: Masami Hiramatsu <[e-mail]>
Signed-off-by: Steven Rostedt (VMware) <[e-mail]>

kernel/trace/trace_kprobe.c

···
 	struct ring_buffer *buffer;
 	int size, dsize, pc;
 	unsigned long irq_flags;
-	struct trace_event_call *call = &tk->tp.call;
+	struct trace_event_call *call = trace_probe_event_call(&tk->tp);
 
 	WARN_ON(call != trace_file->event_call);
 
···
 	struct ring_buffer *buffer;
 	int size, pc, dsize;
 	unsigned long irq_flags;
-	struct trace_event_call *call = &tk->tp.call;
+	struct trace_event_call *call = trace_probe_event_call(&tk->tp);
 
 	WARN_ON(call != trace_file->event_call);
 
···
 static int
 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
 {
-	struct trace_event_call *call = &tk->tp.call;
+	struct trace_event_call *call = trace_probe_event_call(&tk->tp);
 	struct kprobe_trace_entry_head *entry;
 	struct hlist_head *head;
 	int size, __size, dsize;
···
 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
 		    struct pt_regs *regs)
 {
-	struct trace_event_call *call = &tk->tp.call;
+	struct trace_event_call *call = trace_probe_event_call(&tk->tp);
 	struct kretprobe_trace_entry_head *entry;
 	struct hlist_head *head;
 	int size, __size, dsize;
···
 	.trace		= print_kprobe_event
 };
 
-static inline void init_trace_event_call(struct trace_kprobe *tk,
-					 struct trace_event_call *call)
+static inline void init_trace_event_call(struct trace_kprobe *tk)
 {
+	struct trace_event_call *call = trace_probe_event_call(&tk->tp);
+
 	if (trace_kprobe_is_return(tk)) {
 		call->event.funcs = &kretprobe_funcs;
 		call->class->define_fields = kretprobe_event_define_fields;
···
 
 static int register_kprobe_event(struct trace_kprobe *tk)
 {
-	init_trace_event_call(tk, &tk->tp.call);
+	init_trace_event_call(tk);
 
 	return trace_probe_register_event_call(&tk->tp);
 }
···
 		return ERR_CAST(tk);
 	}
 
-	init_trace_event_call(tk, &tk->tp.call);
+	init_trace_event_call(tk);
 
 	if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) {
 		ret = -ENOMEM;
···
 	if (ret < 0)
 		goto error;
 
-	return &tk->tp.call;
+	return trace_probe_event_call(&tk->tp);
 error:
 	free_trace_kprobe(tk);
 	return ERR_PTR(ret);
···
 	mutex_lock(&event_mutex);
 	for_each_trace_kprobe(tk, pos) {
 		list_for_each_entry(file, &tr->events, list)
-			if (file->event_call == &tk->tp.call)
+			if (file->event_call == trace_probe_event_call(&tk->tp))
 				trace_event_enable_disable(file, 1, 0);
 	}
 	mutex_unlock(&event_mutex);
···
 	struct trace_event_file *file;
 
 	list_for_each_entry(file, &tr->events, list)
-		if (file->event_call == &tk->tp.call)
+		if (file->event_call == trace_probe_event_call(&tk->tp))
 			return file;
 
 	return NULL;

kernel/trace/trace_probe.c

···
 
 int traceprobe_set_print_fmt(struct trace_probe *tp, bool is_return)
 {
+	struct trace_event_call *call = trace_probe_event_call(tp);
 	int len;
 	char *print_fmt;
 
···
 
 	/* Second: actually write the @print_fmt */
 	__set_print_fmt(tp, print_fmt, len + 1, is_return);
-	tp->call.print_fmt = print_fmt;
+	call->print_fmt = print_fmt;
 
 	return 0;
 }
···
 
 void trace_probe_cleanup(struct trace_probe *tp)
 {
+	struct trace_event_call *call = trace_probe_event_call(tp);
 	int i;
 
 	for (i = 0; i < tp->nr_args; i++)
 		traceprobe_free_probe_arg(&tp->args[i]);
 
-	kfree(tp->call.class->system);
-	kfree(tp->call.name);
-	kfree(tp->call.print_fmt);
+	kfree(call->class->system);
+	kfree(call->name);
+	kfree(call->print_fmt);
 }
 
 int trace_probe_init(struct trace_probe *tp, const char *event,
 		     const char *group)
 {
+	struct trace_event_call *call = trace_probe_event_call(tp);
+
 	if (!event || !group)
 		return -EINVAL;
 
-	tp->call.class = &tp->class;
-	tp->call.name = kstrdup(event, GFP_KERNEL);
-	if (!tp->call.name)
+	call->class = &tp->class;
+	call->name = kstrdup(event, GFP_KERNEL);
+	if (!call->name)
 		return -ENOMEM;
 
 	tp->class.system = kstrdup(group, GFP_KERNEL);
 	if (!tp->class.system) {
-		kfree(tp->call.name);
-		tp->call.name = NULL;
+		kfree(call->name);
+		call->name = NULL;
 		return -ENOMEM;
 	}
 	INIT_LIST_HEAD(&tp->files);
···
 
 int trace_probe_register_event_call(struct trace_probe *tp)
 {
-	struct trace_event_call *call = &tp->call;
+	struct trace_event_call *call = trace_probe_event_call(tp);
 	int ret;
 
 	ret = register_trace_event(&call->event);

kernel/trace/trace_probe.h

···
 	return tp->call.class->system;
 }
 
+static inline struct trace_event_call *
+	trace_probe_event_call(struct trace_probe *tp)
+{
+	return &tp->call;
+}
+
 static inline int trace_probe_unregister_event_call(struct trace_probe *tp)
 {
 	/* tp->event is unregistered in trace_remove_event_call() */

kernel/trace/trace_uprobe.c

···
 	struct ring_buffer *buffer;
 	void *data;
 	int size, esize;
-	struct trace_event_call *call = &tu->tp.call;
+	struct trace_event_call *call = trace_probe_event_call(&tu->tp);
 
 	WARN_ON(call != trace_file->event_call);
 
···
 			       unsigned long func, struct pt_regs *regs,
 			       struct uprobe_cpu_buffer *ucb, int dsize)
 {
-	struct trace_event_call *call = &tu->tp.call;
+	struct trace_event_call *call = trace_probe_event_call(&tu->tp);
 	struct uprobe_trace_entry_head *entry;
 	struct hlist_head *head;
 	void *data;
···
 	.trace		= print_uprobe_event
 };
 
-static inline void init_trace_event_call(struct trace_uprobe *tu,
-					 struct trace_event_call *call)
+static inline void init_trace_event_call(struct trace_uprobe *tu)
 {
+	struct trace_event_call *call = trace_probe_event_call(&tu->tp);
+
 	call->event.funcs = &uprobe_funcs;
 	call->class->define_fields = uprobe_event_define_fields;
 
···
 
 static int register_uprobe_event(struct trace_uprobe *tu)
 {
-	init_trace_event_call(tu, &tu->tp.call);
+	init_trace_event_call(tu);
 
 	return trace_probe_register_event_call(&tu->tp);
 }
···
 	tu->path = path;
 	tu->ref_ctr_offset = ref_ctr_offset;
 	tu->filename = kstrdup(name, GFP_KERNEL);
-	init_trace_event_call(tu, &tu->tp.call);
+	init_trace_event_call(tu);
 
 	if (traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) {
 		ret = -ENOMEM;
 		goto error;
 	}
 
-	return &tu->tp.call;
+	return trace_probe_event_call(&tu->tp);
 error:
 	free_trace_uprobe(tu);
 	return ERR_PTR(ret);