From 46e5da40aec256155cfedee96dd21a75da941f2c Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Fri, 12 Sep 2014 20:04:52 -0700 Subject: net: qdisc: use rcu prefix and silence sparse warnings Add __rcu notation to qdisc handling by doing this we can make smatch output more legible. And anyways some of the cases should be using rcu_dereference() see qdisc_all_tx_empty(), qdisc_tx_chainging(), and so on. Also *wake_queue() API is commonly called from driver timer routines without rcu lock or rtnl lock. So I added rcu_read_lock() blocks around netif_wake_subqueue and netif_tx_wake_queue. Signed-off-by: John Fastabend Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- net/sched/sch_generic.c | 4 ++-- net/sched/sch_mqprio.c | 6 ++++-- net/sched/sch_teql.c | 13 ++++++++----- 3 files changed, 14 insertions(+), 9 deletions(-) (limited to 'net/sched') diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 19696ebe9ebc..346ef85617d3 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -783,7 +783,7 @@ static void dev_deactivate_queue(struct net_device *dev, struct Qdisc *qdisc_default = _qdisc_default; struct Qdisc *qdisc; - qdisc = dev_queue->qdisc; + qdisc = rtnl_dereference(dev_queue->qdisc); if (qdisc) { spin_lock_bh(qdisc_lock(qdisc)); @@ -876,7 +876,7 @@ static void dev_init_scheduler_queue(struct net_device *dev, { struct Qdisc *qdisc = _qdisc; - dev_queue->qdisc = qdisc; + rcu_assign_pointer(dev_queue->qdisc, qdisc); dev_queue->qdisc_sleeping = qdisc; } diff --git a/net/sched/sch_mqprio.c b/net/sched/sch_mqprio.c index 6749e2f540d0..37e7d25d21f1 100644 --- a/net/sched/sch_mqprio.c +++ b/net/sched/sch_mqprio.c @@ -231,7 +231,7 @@ static int mqprio_dump(struct Qdisc *sch, struct sk_buff *skb) memset(&sch->qstats, 0, sizeof(sch->qstats)); for (i = 0; i < dev->num_tx_queues; i++) { - qdisc = netdev_get_tx_queue(dev, i)->qdisc; + qdisc = rtnl_dereference(netdev_get_tx_queue(dev, i)->qdisc); spin_lock_bh(qdisc_lock(qdisc)); sch->q.qlen += qdisc->q.qlen; sch->bstats.bytes += qdisc->bstats.bytes; @@ -340,7 +340,9 @@ static int mqprio_dump_class_stats(struct Qdisc *sch, unsigned long cl, spin_unlock_bh(d->lock); for (i = tc.offset; i < tc.offset + tc.count; i++) { - qdisc = netdev_get_tx_queue(dev, i)->qdisc; + struct netdev_queue *q = netdev_get_tx_queue(dev, i); + + qdisc = rtnl_dereference(q->qdisc); spin_lock_bh(qdisc_lock(qdisc)); bstats.bytes += qdisc->bstats.bytes; bstats.packets += qdisc->bstats.packets; diff --git a/net/sched/sch_teql.c b/net/sched/sch_teql.c index aaa8d03ed054..5cd291bd00e4 100644 --- a/net/sched/sch_teql.c +++ b/net/sched/sch_teql.c @@ -96,11 +96,14 @@ teql_dequeue(struct Qdisc *sch) struct teql_sched_data *dat = qdisc_priv(sch); struct netdev_queue *dat_queue; struct sk_buff *skb; + struct Qdisc *q; skb = __skb_dequeue(&dat->q); dat_queue = netdev_get_tx_queue(dat->m->dev, 0); + q = rcu_dereference_bh(dat_queue->qdisc); + if (skb == NULL) { - struct net_device *m = qdisc_dev(dat_queue->qdisc); + struct net_device *m = qdisc_dev(q); if (m) { dat->m->slaves = sch; netif_wake_queue(m); @@ -108,7 +111,7 @@ teql_dequeue(struct Qdisc *sch) } else { qdisc_bstats_update(sch, skb); } - sch->q.qlen = dat->q.qlen + dat_queue->qdisc->q.qlen; + sch->q.qlen = dat->q.qlen + q->q.qlen; return skb; } @@ -157,9 +160,9 @@ teql_destroy(struct Qdisc *sch) txq = netdev_get_tx_queue(master->dev, 0); master->slaves = NULL; - root_lock = qdisc_root_sleeping_lock(txq->qdisc); + root_lock = qdisc_root_sleeping_lock(rtnl_dereference(txq->qdisc)); spin_lock_bh(root_lock); - qdisc_reset(txq->qdisc); + qdisc_reset(rtnl_dereference(txq->qdisc)); spin_unlock_bh(root_lock); } } @@ -266,7 +269,7 @@ static inline int teql_resolve(struct sk_buff *skb, struct dst_entry *dst = skb_dst(skb); int res; - if (txq->qdisc == &noop_qdisc) + if (rcu_access_pointer(txq->qdisc) == &noop_qdisc) return -ENODEV; if (!dev->header_ops || !dst) -- cgit v1.2.3