[PATCH 2/3] ftrace: Return EINVAL when writing invalid val to set_ftrace_filter

[Li Zefan <lizf@cn.fujitsu.com>]

Currently it doesn't warn user on invald value:

 # echo nonexist_symbol > set_ftrace_filter

Better make it return failure.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
 kernel/trace/ftrace.c |   12 +++++++++---
 1 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 7cb6f19..e0184b7 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1724,7 +1724,7 @@ ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
 	return ftrace_match(str, regex, len, type);
 }
 
-static void ftrace_match_records(char *buff, int len, int enable)
+static int ftrace_match_records(char *buff, int len, int enable)
 {
 	unsigned int search_len;
 	struct ftrace_page *pg;
@@ -1733,6 +1733,7 @@ static void ftrace_match_records(char *buff, int len, int enable)
 	char *search;
 	int type;
 	int not;
+	int found = 0;
 
 	flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
 	type = filter_parse_regex(buff, len, &search, &not);
@@ -1750,6 +1751,7 @@ static void ftrace_match_records(char *buff, int len, int enable)
 				rec->flags &= ~flag;
 			else
 				rec->flags |= flag;
+			found = 1;
 		}
 		/*
 		 * Only enable filtering if we have a function that
@@ -1759,6 +1761,8 @@ static void ftrace_match_records(char *buff, int len, int enable)
 			ftrace_filtered = 1;
 	} while_for_each_ftrace_rec();
 	mutex_unlock(&ftrace_lock);
+
+	return found;
 }
 
 static int
@@ -2151,8 +2155,10 @@ static int ftrace_process_regex(char *buff, int len, int enable)
 	func = strsep(&next, ":");
 
 	if (!next) {
-		ftrace_match_records(func, len, enable);
-		return 0;
+		if (ftrace_match_records(func, len, enable))
+			return 0;
+		else
+			return ret;
 	}
 
 	/* command found */
-- 
1.6.3