[PATCH 7/7] tracing/filters: Add comment for match callbacks

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

We should be clear on 2 things:

- the length parameter of a match callback includes
  tailing '\0'.

- the string to be searched might not be NULL-terminated.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
 kernel/trace/trace_events_filter.c |   13 ++++++++++++-
 1 files changed, 12 insertions(+), 1 deletions(-)

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 14e83de..4615f62 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -252,7 +252,18 @@ static int filter_pred_none(struct filter_pred *pred, void *event,
 	return 0;
 }
 
-/* Basic regex callbacks */
+/*
+ * regex_match_foo - Basic regex callbacks
+ *
+ * @str: the string to be searched
+ * @r:   the regex structure containing the pattern string
+ * @len: the length of the string to be searched (including '\0')
+ *
+ * Note:
+ * - @str might not be NULL-terminated if it's of type DYN_STRING
+ *   or STATIC_STRING
+ */
+
 static int regex_match_full(char *str, struct regex *r, int len)
 {
 	if (strncmp(str, r->pattern, len) == 0)
-- 
1.6.3