aboutsummaryrefslogtreecommitdiff
path: root/net/sched
diff options
context:
space:
mode:
authorJarek Poplawski <jarkao2@gmail.com>2008-08-22 03:24:05 -0700
committerDavid S. Miller <davem@davemloft.net>2008-08-22 03:31:39 -0700
commitf6e0b239a2657ea8cb67f0d83d0bfdbfd19a481b (patch)
tree9d6e3c97a81869fde3958cdbcf431ee3739f9b2c /net/sched
parent2540e0511ea17e25831be543cdf9381e6209950d (diff)
downloadlinux-2.6.38-lt-ux500-f6e0b239a2657ea8cb67f0d83d0bfdbfd19a481b.tar.gz
pkt_sched: Fix qdisc list locking
Since some qdiscs call qdisc_tree_decrease_qlen() (so qdisc_lookup()) without rtnl_lock(), adding and deleting from a qdisc list needs additional locking. This patch adds global spinlock qdisc_list_lock and wrapper functions for modifying the list. It is considered as a temporary solution until hfsc_dequeue(), netem_dequeue() and tbf_dequeue() (or qdisc_tree_decrease_qlen()) are redone. With feedback from Herbert Xu and David S. Miller. Signed-off-by: Jarek Poplawski <jarkao2@gmail.com> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched')
-rw-r--r--net/sched/sch_api.c44
-rw-r--r--net/sched/sch_generic.c5
2 files changed, 41 insertions, 8 deletions
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 45f442d7de4..e7fb9e0d21b 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -199,19 +199,53 @@ struct Qdisc *qdisc_match_from_root(struct Qdisc *root, u32 handle)
return NULL;
}
+/*
+ * This lock is needed until some qdiscs stop calling qdisc_tree_decrease_qlen()
+ * without rtnl_lock(); currently hfsc_dequeue(), netem_dequeue(), tbf_dequeue()
+ */
+static DEFINE_SPINLOCK(qdisc_list_lock);
+
+static void qdisc_list_add(struct Qdisc *q)
+{
+ if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
+ spin_lock_bh(&qdisc_list_lock);
+ list_add_tail(&q->list, &qdisc_root_sleeping(q)->list);
+ spin_unlock_bh(&qdisc_list_lock);
+ }
+}
+
+void qdisc_list_del(struct Qdisc *q)
+{
+ if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
+ spin_lock_bh(&qdisc_list_lock);
+ list_del(&q->list);
+ spin_unlock_bh(&qdisc_list_lock);
+ }
+}
+EXPORT_SYMBOL(qdisc_list_del);
+
struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle)
{
unsigned int i;
+ struct Qdisc *q;
+
+ spin_lock_bh(&qdisc_list_lock);
for (i = 0; i < dev->num_tx_queues; i++) {
struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
- struct Qdisc *q, *txq_root = txq->qdisc_sleeping;
+ struct Qdisc *txq_root = txq->qdisc_sleeping;
q = qdisc_match_from_root(txq_root, handle);
if (q)
- return q;
+ goto unlock;
}
- return qdisc_match_from_root(dev->rx_queue.qdisc_sleeping, handle);
+
+ q = qdisc_match_from_root(dev->rx_queue.qdisc_sleeping, handle);
+
+unlock:
+ spin_unlock_bh(&qdisc_list_lock);
+
+ return q;
}
static struct Qdisc *qdisc_leaf(struct Qdisc *p, u32 classid)
@@ -810,8 +844,8 @@ qdisc_create(struct net_device *dev, struct netdev_queue *dev_queue,
goto err_out3;
}
}
- if ((parent != TC_H_ROOT) && !(sch->flags & TCQ_F_INGRESS))
- list_add_tail(&sch->list, &dev_queue->qdisc_sleeping->list);
+
+ qdisc_list_add(sch);
return sch;
}
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index c3ed4d44fc1..5f0ade7806a 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -526,10 +526,9 @@ void qdisc_destroy(struct Qdisc *qdisc)
!atomic_dec_and_test(&qdisc->refcnt))
return;
- if (qdisc->parent)
- list_del(&qdisc->list);
-
#ifdef CONFIG_NET_SCHED
+ qdisc_list_del(qdisc);
+
qdisc_put_stab(qdisc->stab);
#endif
gen_kill_estimator(&qdisc->bstats, &qdisc->rate_est);