tracing: trace parser support for set_event

Convert the parsing of the file 'set_event' to use the generic
trace_praser 'trace_get_user' function.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
LKML-Reference: <1252682969-3366-3-git-send-email-jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace_events.c

@@ -230,11 +230,9 @@ static ssize_t
 ftrace_event_write(struct file *file, const char __user *ubuf,
 		   size_t cnt, loff_t *ppos)
 {
+	struct trace_parser parser;
 	size_t read = 0;
-	int i, set = 1;
 	ssize_t ret;
-	char *buf;
-	char ch;
 
 	if (!cnt || cnt < 0)
 		return 0;
@@ -243,60 +241,28 @@ ftrace_event_write(struct file *file, const char __user *ubuf,
 	if (ret < 0)
 		return ret;
 
-	ret = get_user(ch, ubuf++);
-	if (ret)
-		return ret;
-	read++;
-	cnt--;
-
-	/* skip white space */
-	while (cnt && isspace(ch)) {
-		ret = get_user(ch, ubuf++);
-		if (ret)
-			return ret;
-		read++;
-		cnt--;
-	}
-
-	/* Only white space found? */
-	if (isspace(ch)) {
-		file->f_pos += read;
-		ret = read;
-		return ret;
-	}
-
-	buf = kmalloc(EVENT_BUF_SIZE+1, GFP_KERNEL);
-	if (!buf)
+	if (trace_parser_get_init(&parser, EVENT_BUF_SIZE + 1))
 		return -ENOMEM;
 
-	if (cnt > EVENT_BUF_SIZE)
-		cnt = EVENT_BUF_SIZE;
+	read = trace_get_user(&parser, ubuf, cnt, ppos);
 
-	i = 0;
-	while (cnt && !isspace(ch)) {
-		if (!i && ch == '!')
-			set = 0;
-		else
-			buf[i++] = ch;
+	if (trace_parser_loaded((&parser))) {
+		int set = 1;
 
-		ret = get_user(ch, ubuf++);
-		if (ret)
-			goto out_free;
-		read++;
-		cnt--;
-	}
-	buf[i] = 0;
+		if (*parser.buffer == '!')
+			set = 0;
 
-	file->f_pos += read;
+		parser.buffer[parser.idx] = 0;
 
-	ret = ftrace_set_clr_event(buf, set);
+		ret = ftrace_set_clr_event(parser.buffer + !set, set);
 		if (ret)
-		goto out_free;
+			goto out_put;
+	}
 
 	ret = read;
 
- out_free:
-	kfree(buf);
+ out_put:
+	trace_parser_put(&parser);
 
 	return ret;
 }