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authorJohn Fastabend <john.fastabend@gmail.com>2014-09-12 20:04:52 -0700
committerDavid S. Miller <davem@davemloft.net>2014-09-13 12:30:25 -0400
commit46e5da40aec256155cfedee96dd21a75da941f2c (patch)
treecc3986c52025d252c2a063053692595e60c80e13 /net/sched/sch_teql.c
parentd1015645dd535bbf10e52a3ef6d02ee0c3e0b267 (diff)
downloadlinux-46e5da40aec256155cfedee96dd21a75da941f2c.tar.gz
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 <john.r.fastabend@intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/sch_teql.c')
-rw-r--r--net/sched/sch_teql.c13
1 files changed, 8 insertions, 5 deletions
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)