Merge to Fedora kernel-2.6.7-1.492

[linux-2.6.git] / net / sched / sch_generic.c

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 97b5625..672650c 100644 (file)
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -30,6 +30,7 @@
 #include <linux/skbuff.h>
 #include <linux/rtnetlink.h>
 #include <linux/init.h>
+#include <linux/rcupdate.h>
 #include <net/sock.h>
 #include <net/pkt_sched.h>
 
@@ -385,8 +386,11 @@ struct Qdisc * qdisc_create_dflt(struct net_device *dev, struct Qdisc_ops *ops)
        sch->enqueue = ops->enqueue;
        sch->dequeue = ops->dequeue;
        sch->dev = dev;
-       sch->stats.lock = &dev->queue_lock;
+       sch->stats_lock = &dev->queue_lock;
        atomic_set(&sch->refcnt, 1);
+       /* enqueue is accessed locklessly - make sure it's visible
+        * before we set a netdevice's qdisc pointer to sch */
+       smp_wmb();
        if (!ops->init || ops->init(sch, NULL) == 0)
                return sch;
 
@@ -404,18 +408,36 @@ void qdisc_reset(struct Qdisc *qdisc)
                ops->reset(qdisc);
 }
 
+/* this is the rcu callback function to clean up a qdisc when there 
+ * are no further references to it */
+
+static void __qdisc_destroy(struct rcu_head *head)
+{
+       struct Qdisc *qdisc = container_of(head, struct Qdisc, q_rcu);
+       struct Qdisc_ops  *ops = qdisc->ops;
+
+#ifdef CONFIG_NET_ESTIMATOR
+       qdisc_kill_estimator(&qdisc->stats);
+#endif
+       if (ops->reset)
+               ops->reset(qdisc);
+       if (ops->destroy)
+               ops->destroy(qdisc);
+       module_put(ops->owner);
+
+       if (!(qdisc->flags&TCQ_F_BUILTIN))
+               kfree(qdisc);
+}
+
 /* Under dev->queue_lock and BH! */
 
 void qdisc_destroy(struct Qdisc *qdisc)
 {
-       struct Qdisc_ops *ops = qdisc->ops;
-       struct net_device *dev;
+       struct net_device *dev = qdisc->dev;
 
        if (!atomic_dec_and_test(&qdisc->refcnt))
                return;
 
-       dev = qdisc->dev;
-
        if (dev) {
                struct Qdisc *q, **qp;
                for (qp = &qdisc->dev->qdisc_list; (q=*qp) != NULL; qp = &q->next) {
@@ -425,16 +447,9 @@ void qdisc_destroy(struct Qdisc *qdisc)
                        }
                }
        }
-#ifdef CONFIG_NET_ESTIMATOR
-       qdisc_kill_estimator(&qdisc->stats);
-#endif
-       if (ops->reset)
-               ops->reset(qdisc);
-       if (ops->destroy)
-               ops->destroy(qdisc);
-       module_put(ops->owner);
-       if (!(qdisc->flags&TCQ_F_BUILTIN))
-               kfree(qdisc);
+
+       call_rcu(&qdisc->q_rcu, __qdisc_destroy);
+
 }