[RFC][PATCH v2 3/7] trace_events_filter.c: switch to memcmp() and memmem() for matching

[Al Viro <viro@ZenIV.linux.org.uk>]

From: Al Viro <viro@zeniv.linux.org.uk>

we know the lengths in advance...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 kernel/trace/trace_events_filter.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index ced69da..6c4a96b 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -271,21 +271,25 @@ static int filter_pred_none(struct filter_pred *pred, void *event)
 
 static int regex_match_full(char *str, struct regex *r, int len)
 {
-	if (strncmp(str, r->pattern, len) == 0)
+	if (len - 1 != r->len)
+		return 0;
+	if (memcmp(str, r->pattern, r->len) == 0)
 		return 1;
 	return 0;
 }
 
 static int regex_match_front(char *str, struct regex *r, int len)
 {
-	if (strncmp(str, r->pattern, r->len) == 0)
+	if (len - 1 < r->len)
+		return 0;
+	if (memcmp(str, r->pattern, r->len) == 0)
 		return 1;
 	return 0;
 }
 
 static int regex_match_middle(char *str, struct regex *r, int len)
 {
-	if (strnstr(str, r->pattern, len))
+	if (memmem(str, len, r->pattern, r->len))
 		return 1;
 	return 0;
 }
-- 
2.1.4