[NET_SCHED] cls_u32: refcounting fix for u32_delete()

Deleting of nonroot hnodes mostly doesn't work in u32_delete():
refcnt == 1 is expected, but such hnodes' refcnts are initialized
with 0 and charged only with "link" nodes. Now they'll start with
1 like usual. Thanks to Patrick McHardy for an improving suggestion.

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Acked-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 3 deletions

diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index c5c16b4b6e98..4d755444c449 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -411,8 +411,10 @@ static void u32_destroy(struct tcf_proto *tp)
                         }
                 }
 
-                for (ht=tp_c->hlist; ht; ht = ht->next)
+                for (ht = tp_c->hlist; ht; ht = ht->next) {
+                        ht->refcnt--;
                         u32_clear_hnode(tp, ht);
+                }
 
                 while ((ht = tp_c->hlist) != NULL) {
                         tp_c->hlist = ht->next;
@@ -441,8 +443,12 @@ static int u32_delete(struct tcf_proto *tp, unsigned long arg)
         if (tp->root == ht)
                 return -EINVAL;
 
-        if (--ht->refcnt == 0)
+        if (ht->refcnt == 1) {
+                ht->refcnt--;
                 u32_destroy_hnode(tp, ht);
+        } else {
+                return -EBUSY;
+        }
 
         return 0;
 }
@@ -568,7 +574,7 @@ static int u32_change(struct tcf_proto *tp, unsigned long base, u32 handle,
                 if (ht == NULL)
                         return -ENOBUFS;
                 ht->tp_c = tp_c;
-                ht->refcnt = 0;
+                ht->refcnt = 1;
                 ht->divisor = divisor;
                 ht->handle = handle;
                 ht->prio = tp->prio;