tracing: Account for variables in named trigger compatibility

Named triggers must also have the same set of variables in order to be
considered compatible - update the trigger match test to account for
that.

The reason for this requirement is that named triggers with variables
are meant to allow one or more events to set the same variable.

Link: http://lkml.kernel.org/r/a17eae6328a99917f9d5c66129c9fcd355279ee9.1516069914.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

kernel/trace/trace_events_hist.c

@@ -1610,7 +1610,7 @@ static int event_hist_trigger_print(struct seq_file *m,
 		sort_key = &hist_data->sort_keys[i];
 		idx = sort_key->field_idx;
 
-		if (WARN_ON(idx >= TRACING_MAP_FIELDS_MAX))
+		if (WARN_ON(idx >= HIST_FIELDS_MAX))
 			return -EINVAL;
 
 		if (i > 0)
@@ -1798,6 +1798,11 @@ static bool hist_trigger_match(struct event_trigger_data *data,
 			return false;
 		if (key_field->is_signed != key_field_test->is_signed)
 			return false;
+		if (!!key_field->var.name != !!key_field_test->var.name)
+			return false;
+		if (key_field->var.name &&
+		    strcmp(key_field->var.name, key_field_test->var.name) != 0)
+			return false;
 	}
 
 	for (i = 0; i < hist_data->n_sort_keys; i++) {