pkt_sched: Add some basic qdisc class ops verification. Was: [PATCH] sfq: add dummy bind/unbind handles

Verify in register_qdisc() some basic qdisc class handlers are present.

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 17 insertions, 5 deletions

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index b9e8c3b7d406..8ed2f5649029 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -150,22 +150,34 @@ int register_qdisc(struct Qdisc_ops *qops)
         if (qops->enqueue == NULL)
                 qops->enqueue = noop_qdisc_ops.enqueue;
         if (qops->peek == NULL) {
-                if (qops->dequeue == NULL) {
+                if (qops->dequeue == NULL)
                         qops->peek = noop_qdisc_ops.peek;
-                } else {
-                        rc = -EINVAL;
-                        goto out;
-                }
+                else
+                        goto out_einval;
         }
         if (qops->dequeue == NULL)
                 qops->dequeue = noop_qdisc_ops.dequeue;
 
+        if (qops->cl_ops) {
+                const struct Qdisc_class_ops *cops = qops->cl_ops;
+
+                if (!(cops->get && cops->put))
+                        goto out_einval;
+
+                if (cops->tcf_chain && !(cops->bind_tcf && cops->unbind_tcf))
+                        goto out_einval;
+        }
+
         qops->next = NULL;
         *qp = qops;
         rc = 0;
 out:
         write_unlock(&qdisc_mod_lock);
         return rc;
+
+out_einval:
+        rc = -EINVAL;
+        goto out;
 }
 EXPORT_SYMBOL(register_qdisc);