};
 
 struct opstack_op {
-       int op;
+       enum filter_op_ids op;
        struct list_head list;
 };
 
 struct postfix_elt {
-       int op;
+       enum filter_op_ids op;
        char *operand;
        struct list_head list;
 };
        return FILTER_OTHER;
 }
 
-static bool is_legal_op(struct ftrace_event_field *field, int op)
+static bool is_legal_op(struct ftrace_event_field *field, enum filter_op_ids op)
 {
        if (is_string_field(field) &&
            (op != OP_EQ && op != OP_NE && op != OP_GLOB))
        return true;
 }
 
-static filter_pred_fn_t select_comparison_fn(int op, int field_size,
-                                            int field_is_signed)
+static filter_pred_fn_t select_comparison_fn(enum filter_op_ids op,
+                                           int field_size, int field_is_signed)
 {
        filter_pred_fn_t fn = NULL;
 
        return 0;
 }
 
-static int filter_opstack_push(struct filter_parse_state *ps, int op)
+static int filter_opstack_push(struct filter_parse_state *ps,
+                              enum filter_op_ids op)
 {
        struct opstack_op *opstack_op;
 
 static int filter_opstack_pop(struct filter_parse_state *ps)
 {
        struct opstack_op *opstack_op;
-       int op;
+       enum filter_op_ids op;
 
        if (filter_opstack_empty(ps))
                return OP_NONE;
        return 0;
 }
 
-static int postfix_append_op(struct filter_parse_state *ps, int op)
+static int postfix_append_op(struct filter_parse_state *ps, enum filter_op_ids op)
 {
        struct postfix_elt *elt;
 
 
 static int filter_parse(struct filter_parse_state *ps)
 {
+       enum filter_op_ids op, top_op;
        int in_string = 0;
-       int op, top_op;
        char ch;
 
        while ((ch = infix_next(ps))) {
 
 static struct filter_pred *create_pred(struct filter_parse_state *ps,
                                       struct trace_event_call *call,
-                                      int op, char *operand1, char *operand2)
+                                      enum filter_op_ids op,
+                                      char *operand1, char *operand2)
 {
        struct ftrace_event_field *field;
        static struct filter_pred pred;