[PATCH net-next 11/11] net: sched: cls_u32: simplify the hell out u32_delete() emptiness check

[Jamal Hadi Salim]

From: Al Viro <v...@zeniv.linux.org.uk>

Now that we have the knode count, we can instantly check if
any hnodes are non-empty.  And that kills the check for extra
references to root hnode - those could happen only if there was
a knode to carry such a link.

Signed-off-by: Al Viro <v...@zeniv.linux.org.uk>
Signed-off-by: Jamal Hadi Salim <j...@mojatatu.com>
---
 net/sched/cls_u32.c | 48 +-----------------------------------------------
 1 file changed, 1 insertion(+), 47 deletions(-)

diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index 61593bee08db..ac79a40a0392 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -627,17 +627,6 @@ static int u32_destroy_hnode(struct tcf_proto *tp, struct 
tc_u_hnode *ht,
        return -ENOENT;
 }
 
-static bool ht_empty(struct tc_u_hnode *ht)
-{
-       unsigned int h;
-
-       for (h = 0; h <= ht->divisor; h++)
-               if (rcu_access_pointer(ht->ht[h]))
-                       return false;
-
-       return true;
-}
-
 static void u32_destroy(struct tcf_proto *tp, struct netlink_ext_ack *extack)
 {
        struct tc_u_common *tp_c = tp->data;
@@ -675,13 +664,9 @@ static int u32_delete(struct tcf_proto *tp, void *arg, 
bool *last,
                      struct netlink_ext_ack *extack)
 {
        struct tc_u_hnode *ht = arg;
-       struct tc_u_hnode *root_ht = rtnl_dereference(tp->root);
        struct tc_u_common *tp_c = tp->data;
        int ret = 0;
 
-       if (ht == NULL)
-               goto out;
-
        if (TC_U32_KEY(ht->handle)) {
                u32_remove_hw_knode(tp, (struct tc_u_knode *)ht, extack);
                ret = u32_delete_key(tp, (struct tc_u_knode *)ht);
@@ -702,38 +687,7 @@ static int u32_delete(struct tcf_proto *tp, void *arg, 
bool *last,
        }
 
 out:
-       *last = true;
-       if (root_ht) {
-               if (root_ht->refcnt > 1) {
-                       *last = false;
-                       goto ret;
-               }
-               if (root_ht->refcnt == 1) {
-                       if (!ht_empty(root_ht)) {
-                               *last = false;
-                               goto ret;
-                       }
-               }
-       }
-
-       if (tp_c->refcnt > 1) {
-               *last = false;
-               goto ret;
-       }
-
-       if (tp_c->refcnt == 1) {
-               struct tc_u_hnode *ht;
-
-               for (ht = rtnl_dereference(tp_c->hlist);
-                    ht;
-                    ht = rtnl_dereference(ht->next))
-                       if (!ht_empty(ht)) {
-                               *last = false;
-                               break;
-                       }
-       }
-
-ret:
+       *last = tp_c->refcnt == 1 && tp_c->knodes == 0;
        return ret;
 }
 
-- 
2.11.0