pkt_sched: Add and use qdisc_root() and qdisc_root_lock().
When code wants to lock the qdisc tree state, the logic
operation it's doing is locking the top-level qdisc that
sits of the root of the netdev_queue.
Add qdisc_root_lock() to represent this and convert the
easiest cases.
In order for this to work out in all cases, we have to
hook up the noop_qdisc to a dummy netdev_queue.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c
index 4efc836..37ae653 100644
--- a/net/sched/sch_cbq.c
+++ b/net/sched/sch_cbq.c
@@ -1744,12 +1744,13 @@
if (--cl->refcnt == 0) {
#ifdef CONFIG_NET_CLS_ACT
+ spinlock_t *root_lock = qdisc_root_lock(sch);
struct cbq_sched_data *q = qdisc_priv(sch);
- spin_lock_bh(&sch->dev_queue->lock);
+ spin_lock_bh(root_lock);
if (q->rx_class == cl)
q->rx_class = NULL;
- spin_unlock_bh(&sch->dev_queue->lock);
+ spin_unlock_bh(root_lock);
#endif
cbq_destroy_class(sch, cl);
@@ -1828,7 +1829,7 @@
if (tca[TCA_RATE])
gen_replace_estimator(&cl->bstats, &cl->rate_est,
- &sch->dev_queue->lock,
+ qdisc_root_lock(sch),
tca[TCA_RATE]);
return 0;
}
@@ -1919,7 +1920,7 @@
if (tca[TCA_RATE])
gen_new_estimator(&cl->bstats, &cl->rate_est,
- &sch->dev_queue->lock, tca[TCA_RATE]);
+ qdisc_root_lock(sch), tca[TCA_RATE]);
*arg = (unsigned long)cl;
return 0;