[PATCH 5/7] tracing: Use hist trigger's var_ref array to destroy var_refs

[Tom Zanussi]

From: Tom Zanussi <tom.zanu...@linux.intel.com>

Since every var ref for a trigger has an entry in the var_ref[] array,
use that to destroy the var_refs, instead of piecemeal via the field
expressions.

This allows us to avoid having to keep and treat differently separate
lists for the action-related references, which future patches will
remove.

Signed-off-by: Tom Zanussi <tom.zanu...@linux.intel.com>
---
 kernel/trace/trace_events_hist.c | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 9d4cf7a8a95b..725d22f5372f 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -2193,6 +2193,15 @@ static int contains_operator(char *str)
        return field_op;
 }
 
+static void __destroy_hist_field(struct hist_field *hist_field)
+{
+       kfree(hist_field->var.name);
+       kfree(hist_field->name);
+       kfree(hist_field->type);
+
+       kfree(hist_field);
+}
+
 static void destroy_hist_field(struct hist_field *hist_field,
                               unsigned int level)
 {
@@ -2204,14 +2213,13 @@ static void destroy_hist_field(struct hist_field 
*hist_field,
        if (!hist_field)
                return;
 
+       if (hist_field->flags & HIST_FIELD_FL_VAR_REF)
+               return; /* var refs will be destroyed separately */
+
        for (i = 0; i < HIST_FIELD_OPERANDS_MAX; i++)
                destroy_hist_field(hist_field->operands[i], level + 1);
 
-       kfree(hist_field->var.name);
-       kfree(hist_field->name);
-       kfree(hist_field->type);
-
-       kfree(hist_field);
+       __destroy_hist_field(hist_field);
 }
 
 static struct hist_field *create_hist_field(struct hist_trigger_data 
*hist_data,
@@ -2338,6 +2346,12 @@ static void destroy_hist_fields(struct hist_trigger_data 
*hist_data)
                        hist_data->fields[i] = NULL;
                }
        }
+
+       for (i = 0; i < hist_data->n_var_refs; i++) {
+               WARN_ON(!(hist_data->var_refs[i]->flags & 
HIST_FIELD_FL_VAR_REF));
+               __destroy_hist_field(hist_data->var_refs[i]);
+               hist_data->var_refs[i] = NULL;
+       }
 }
 
 static int init_var_ref(struct hist_field *ref_field,
-- 
2.14.1