tracing/probes: Integrate duplicate set_print_fmt()

The set_print_fmt() functions are implemented almost same for
[ku]probes.  Move it to a common place and get rid of the duplication.
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

kernel/trace/trace_kprobe.c

@@ -964,67 +964,6 @@ static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
 	return 0;
 }
 
-static int __set_print_fmt(struct trace_kprobe *tk, char *buf, int len)
-{
-	int i;
-	int pos = 0;
-
-	const char *fmt, *arg;
-
-	if (!trace_kprobe_is_return(tk)) {
-		fmt = "(%lx)";
-		arg = "REC->" FIELD_STRING_IP;
-	} else {
-		fmt = "(%lx <- %lx)";
-		arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
-	}
-
-	/* When len=0, we just calculate the needed length */
-#define LEN_OR_ZERO (len ? len - pos : 0)
-
-	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
-
-	for (i = 0; i < tk->tp.nr_args; i++) {
-		pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
-				tk->tp.args[i].name, tk->tp.args[i].type->fmt);
-	}
-
-	pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
-
-	for (i = 0; i < tk->tp.nr_args; i++) {
-		if (strcmp(tk->tp.args[i].type->name, "string") == 0)
-			pos += snprintf(buf + pos, LEN_OR_ZERO,
-					", __get_str(%s)",
-					tk->tp.args[i].name);
-		else
-			pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
-					tk->tp.args[i].name);
-	}
-
-#undef LEN_OR_ZERO
-
-	/* return the length of print_fmt */
-	return pos;
-}
-
-static int set_print_fmt(struct trace_kprobe *tk)
-{
-	int len;
-	char *print_fmt;
-
-	/* First: called with 0 length to calculate the needed length */
-	len = __set_print_fmt(tk, NULL, 0);
-	print_fmt = kmalloc(len + 1, GFP_KERNEL);
-	if (!print_fmt)
-		return -ENOMEM;
-
-	/* Second: actually write the @print_fmt */
-	__set_print_fmt(tk, print_fmt, len + 1);
-	tk->tp.call.print_fmt = print_fmt;
-
-	return 0;
-}
-
 #ifdef CONFIG_PERF_EVENTS
 
 /* Kprobe profile handler */
@@ -1175,7 +1114,7 @@ static int register_kprobe_event(struct trace_kprobe *tk)
 		call->event.funcs = &kprobe_funcs;
 		call->class->define_fields = kprobe_event_define_fields;
 	}
-	if (set_print_fmt(tk) < 0)
+	if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
 		return -ENOMEM;
 	ret = register_ftrace_event(&call->event);
 	if (!ret) {

kernel/trace/trace_probe.c

@@ -837,3 +837,65 @@ ssize_t traceprobe_probes_write(struct file *file, const char __user *buffer,
 
 	return ret;
 }
+
+static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
+			   bool is_return)
+{
+	int i;
+	int pos = 0;
+
+	const char *fmt, *arg;
+
+	if (!is_return) {
+		fmt = "(%lx)";
+		arg = "REC->" FIELD_STRING_IP;
+	} else {
+		fmt = "(%lx <- %lx)";
+		arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
+	}
+
+	/* When len=0, we just calculate the needed length */
+#define LEN_OR_ZERO (len ? len - pos : 0)
+
+	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
+
+	for (i = 0; i < tp->nr_args; i++) {
+		pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
+				tp->args[i].name, tp->args[i].type->fmt);
+	}
+
+	pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
+
+	for (i = 0; i < tp->nr_args; i++) {
+		if (strcmp(tp->args[i].type->name, "string") == 0)
+			pos += snprintf(buf + pos, LEN_OR_ZERO,
+					", __get_str(%s)",
+					tp->args[i].name);
+		else
+			pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
+					tp->args[i].name);
+	}
+
+#undef LEN_OR_ZERO
+
+	/* return the length of print_fmt */
+	return pos;
+}
+
+int set_print_fmt(struct trace_probe *tp, bool is_return)
+{
+	int len;
+	char *print_fmt;
+
+	/* First: called with 0 length to calculate the needed length */
+	len = __set_print_fmt(tp, NULL, 0, is_return);
+	print_fmt = kmalloc(len + 1, GFP_KERNEL);
+	if (!print_fmt)
+		return -ENOMEM;
+
+	/* Second: actually write the @print_fmt */
+	__set_print_fmt(tp, print_fmt, len + 1, is_return);
+	tp->call.print_fmt = print_fmt;
+
+	return 0;
+}

kernel/trace/trace_probe.h

@@ -226,3 +226,5 @@ store_trace_args(int ent_size, struct trace_probe *tp, struct pt_regs *regs,
 				   data + tp->args[i].offset);
 	}
 }
+
+extern int set_print_fmt(struct trace_probe *tp, bool is_return);

kernel/trace/trace_uprobe.c

@@ -682,59 +682,6 @@ static int uprobe_event_define_fields(struct ftrace_event_call *event_call)
 	return 0;
 }
 
-#define LEN_OR_ZERO		(len ? len - pos : 0)
-static int __set_print_fmt(struct trace_uprobe *tu, char *buf, int len)
-{
-	const char *fmt, *arg;
-	int i;
-	int pos = 0;
-
-	if (is_ret_probe(tu)) {
-		fmt = "(%lx <- %lx)";
-		arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
-	} else {
-		fmt = "(%lx)";
-		arg = "REC->" FIELD_STRING_IP;
-	}
-
-	/* When len=0, we just calculate the needed length */
-
-	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
-
-	for (i = 0; i < tu->tp.nr_args; i++) {
-		pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
-				tu->tp.args[i].name, tu->tp.args[i].type->fmt);
-	}
-
-	pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
-
-	for (i = 0; i < tu->tp.nr_args; i++) {
-		pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
-				tu->tp.args[i].name);
-	}
-
-	return pos;	/* return the length of print_fmt */
-}
-#undef LEN_OR_ZERO
-
-static int set_print_fmt(struct trace_uprobe *tu)
-{
-	char *print_fmt;
-	int len;
-
-	/* First: called with 0 length to calculate the needed length */
-	len = __set_print_fmt(tu, NULL, 0);
-	print_fmt = kmalloc(len + 1, GFP_KERNEL);
-	if (!print_fmt)
-		return -ENOMEM;
-
-	/* Second: actually write the @print_fmt */
-	__set_print_fmt(tu, print_fmt, len + 1);
-	tu->tp.call.print_fmt = print_fmt;
-
-	return 0;
-}
-
 #ifdef CONFIG_PERF_EVENTS
 static bool
 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
@@ -966,7 +913,7 @@ static int register_uprobe_event(struct trace_uprobe *tu)
 	call->event.funcs = &uprobe_funcs;
 	call->class->define_fields = uprobe_event_define_fields;
 
-	if (set_print_fmt(tu) < 0)
+	if (set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0)
 		return -ENOMEM;
 
 	ret = register_ftrace_event(&call->event);