tracing/filter: Use static allocation for filter predicates

Don't dynamically allocate filter_pred struct, use static memory.
This way we can get rid of the code managing the dynamic filter_pred
struct object.

The create_pred function integrates create_logical_pred function.
This way the static predicate memory is returned only from
one place.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1313072754-4620-2-git-send-email-jolsa@redhat.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 16 insertions, 41 deletions

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 256764ecccd6..cb295a117ee7 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -630,11 +630,7 @@ find_event_field(struct ftrace_event_call *call, char *name)
 
 static void filter_free_pred(struct filter_pred *pred)
 {
-        if (!pred)
-                return;
-
         kfree(pred->field_name);
-        kfree(pred);
 }
 
 static void filter_clear_pred(struct filter_pred *pred)
@@ -1302,39 +1298,30 @@ parse_operand:
         return 0;
 }
 
-static struct filter_pred *create_pred(int op, char *operand1, char *operand2)
+static struct filter_pred *create_pred(struct filter_parse_state *ps,
+                                       int op, char *operand1, char *operand2)
 {
-        struct filter_pred *pred;
+        static struct filter_pred pred;
 
-        pred = kzalloc(sizeof(*pred), GFP_KERNEL);
-        if (!pred)
-                return NULL;
+        memset(&pred, 0, sizeof(pred));
+        pred.op = op;
 
-        pred->field_name = kstrdup(operand1, GFP_KERNEL);
-        if (!pred->field_name) {
-                kfree(pred);
+        if (op == OP_AND || op == OP_OR)
+                return &pred;
+
+        if (!operand1 || !operand2) {
+                parse_error(ps, FILT_ERR_MISSING_FIELD, 0);
                 return NULL;
         }
 
-        strcpy(pred->regex.pattern, operand2);
-        pred->regex.len = strlen(pred->regex.pattern);
-
-        pred->op = op;
-
-        return pred;
-}
-
-static struct filter_pred *create_logical_pred(int op)
-{
-        struct filter_pred *pred;
-
-        pred = kzalloc(sizeof(*pred), GFP_KERNEL);
-        if (!pred)
+        pred.field_name = kstrdup(operand1, GFP_KERNEL);
+        if (!pred.field_name)
                 return NULL;
 
-        pred->op = op;
+        strcpy(pred.regex.pattern, operand2);
+        pred.regex.len = strlen(pred.regex.pattern);
 
-        return pred;
+        return &pred;
 }
 
 static int check_preds(struct filter_parse_state *ps)
@@ -1643,19 +1630,7 @@ static int replace_preds(struct ftrace_event_call *call,
                         goto fail;
                 }
 
-                if (elt->op == OP_AND || elt->op == OP_OR) {
-                        pred = create_logical_pred(elt->op);
-                        goto add_pred;
-                }
-
-                if (!operand1 || !operand2) {
-                        parse_error(ps, FILT_ERR_MISSING_FIELD, 0);
-                        err = -EINVAL;
-                        goto fail;
-                }
-
-                pred = create_pred(elt->op, operand1, operand2);
-add_pred:
+                pred = create_pred(ps, elt->op, operand1, operand2);
                 if (!pred) {
                         err = -ENOMEM;
                         goto fail;