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>
diff --git a/net/core/dev.c b/net/core/dev.c
index 3c6a967..b3d6dbc 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2177,6 +2177,53 @@
return (struct dev_kfree_skb_cb *)skb->cb;
}
+void netif_schedule_queue(struct netdev_queue *txq)
+{
+ rcu_read_lock();
+ if (!(txq->state & QUEUE_STATE_ANY_XOFF)) {
+ struct Qdisc *q = rcu_dereference(txq->qdisc);
+
+ __netif_schedule(q);
+ }
+ rcu_read_unlock();
+}
+EXPORT_SYMBOL(netif_schedule_queue);
+
+/**
+ * netif_wake_subqueue - allow sending packets on subqueue
+ * @dev: network device
+ * @queue_index: sub queue index
+ *
+ * Resume individual transmit queue of a device with multiple transmit queues.
+ */
+void netif_wake_subqueue(struct net_device *dev, u16 queue_index)
+{
+ struct netdev_queue *txq = netdev_get_tx_queue(dev, queue_index);
+
+ if (test_and_clear_bit(__QUEUE_STATE_DRV_XOFF, &txq->state)) {
+ struct Qdisc *q;
+
+ rcu_read_lock();
+ q = rcu_dereference(txq->qdisc);
+ __netif_schedule(q);
+ rcu_read_unlock();
+ }
+}
+EXPORT_SYMBOL(netif_wake_subqueue);
+
+void netif_tx_wake_queue(struct netdev_queue *dev_queue)
+{
+ if (test_and_clear_bit(__QUEUE_STATE_DRV_XOFF, &dev_queue->state)) {
+ struct Qdisc *q;
+
+ rcu_read_lock();
+ q = rcu_dereference(dev_queue->qdisc);
+ __netif_schedule(q);
+ rcu_read_unlock();
+ }
+}
+EXPORT_SYMBOL(netif_tx_wake_queue);
+
void __dev_kfree_skb_irq(struct sk_buff *skb, enum skb_free_reason reason)
{
unsigned long flags;
@@ -3432,7 +3479,7 @@
skb->tc_verd = SET_TC_RTTL(skb->tc_verd, ttl);
skb->tc_verd = SET_TC_AT(skb->tc_verd, AT_INGRESS);
- q = rxq->qdisc;
+ q = rcu_dereference(rxq->qdisc);
if (q != &noop_qdisc) {
spin_lock(qdisc_lock(q));
if (likely(!test_bit(__QDISC_STATE_DEACTIVATED, &q->state)))
@@ -3449,7 +3496,7 @@
{
struct netdev_queue *rxq = rcu_dereference(skb->dev->ingress_queue);
- if (!rxq || rxq->qdisc == &noop_qdisc)
+ if (!rxq || rcu_access_pointer(rxq->qdisc) == &noop_qdisc)
goto out;
if (*pt_prev) {