[PATCH] tracing: Fix unsigned comparison to zero in hist trigger code

[Steven Rostedt (Red Hat)]

Fengguang Wu's bot found two comparisons of unsigned integers to zero. These
were real bugs, as it would miss error conditions returned to zero.

trace_events_hist.c:426:6-9: WARNING: Unsigned expression compared with zero: idx < 0
trace_events_hist.c:568:5-14: WARNING: Unsigned expression compared with zero: n_entries < 0

Reported-by: kbuild test robot <fengguang.wu@xxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
 kernel/trace/trace_events_hist.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 5aa16224036b..92c9f3666fae 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -734,7 +734,7 @@ static int create_tracing_map_fields(struct hist_trigger_data *hist_data)
 	struct tracing_map *map = hist_data->map;
 	struct ftrace_event_field *field;
 	struct hist_field *hist_field;
-	unsigned int i, idx;
+	int i, idx;
 
 	for_each_hist_field(i, hist_data) {
 		hist_field = hist_data->fields[i];
@@ -1036,7 +1036,7 @@ static int print_entries(struct seq_file *m,
 {
 	struct tracing_map_sort_entry **sort_entries = NULL;
 	struct tracing_map *map = hist_data->map;
-	unsigned int i, n_entries;
+	int i, n_entries;
 
 	n_entries = tracing_map_sort_entries(map, hist_data->sort_keys,
 					     hist_data->n_sort_keys,
-- 
1.8.3.1