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>

1 files changed, 4 insertions, 25 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index ba72f6baae1a..ae721f53739e 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -543,7 +543,7 @@ struct netdev_queue {
  * read mostly part
  */
         struct net_device       *dev;
-        struct Qdisc            *qdisc;
+        struct Qdisc __rcu      *qdisc;
         struct Qdisc            *qdisc_sleeping;
 #ifdef CONFIG_SYSFS
         struct kobject          kobj;
@@ -2356,12 +2356,7 @@ static inline void input_queue_tail_incr_save(struct softnet_data *sd,
 DECLARE_PER_CPU_ALIGNED(struct softnet_data, softnet_data);
 
 void __netif_schedule(struct Qdisc *q);
-
-static inline void netif_schedule_queue(struct netdev_queue *txq)
-{
-        if (!(txq->state & QUEUE_STATE_ANY_XOFF))
-                __netif_schedule(txq->qdisc);
-}
+void netif_schedule_queue(struct netdev_queue *txq);
 
 static inline void netif_tx_schedule_all(struct net_device *dev)
 {
@@ -2397,11 +2392,7 @@ static inline void netif_tx_start_all_queues(struct net_device *dev)
         }
 }
 
-static inline void netif_tx_wake_queue(struct netdev_queue *dev_queue)
-{
-        if (test_and_clear_bit(__QUEUE_STATE_DRV_XOFF, &dev_queue->state))
-                __netif_schedule(dev_queue->qdisc);
-}
+void netif_tx_wake_queue(struct netdev_queue *dev_queue);
 
 /**
  *      netif_wake_queue - restart transmit
@@ -2673,19 +2664,7 @@ static inline bool netif_subqueue_stopped(const struct net_device *dev,
         return __netif_subqueue_stopped(dev, skb_get_queue_mapping(skb));
 }
 
-/**
- *      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.
- */
-static inline 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))
-                __netif_schedule(txq->qdisc);
-}
+void netif_wake_subqueue(struct net_device *dev, u16 queue_index);
 
 #ifdef CONFIG_XPS
 int netif_set_xps_queue(struct net_device *dev, const struct cpumask *mask,