pkt_sched: Kill netdev_queue lock.

We can simply use the qdisc->q.lock for all of the
qdisc tree synchronization.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ifb.c b/drivers/net/ifb.c
index 897b05e..0960e69 100644 (file)
--- a/drivers/net/ifb.c
+++ b/drivers/net/ifb.c
@@ -35,7 +35,6 @@
 #include <linux/moduleparam.h>
 #include <net/pkt_sched.h>
 #include <net/net_namespace.h>
-#include <linux/lockdep.h>
 
 #define TX_TIMEOUT  (2*HZ)
 
@@ -228,22 +227,6 @@ static struct rtnl_link_ops ifb_link_ops __read_mostly = {
 module_param(numifbs, int, 0);
 MODULE_PARM_DESC(numifbs, "Number of ifb devices");
 
-/*
- * dev_ifb's TX queue lock is usually taken after dev->rx_queue.lock,
- * reversely to e.g. qdisc_lock_tree(). It should be safe until
- * ifb doesn't take dev's TX queue lock with dev_ifb->rx_queue.lock.
- * But lockdep should know that ifb has different locks from dev.
- */
-static struct lock_class_key ifb_tx_queue_lock_key;
-static struct lock_class_key ifb_rx_queue_lock_key;
-
-static void set_tx_lockdep_key(struct net_device *dev,
-                              struct netdev_queue *txq,
-                              void *_unused)
-{
-       lockdep_set_class(&txq->lock, &ifb_tx_queue_lock_key);
-}
-
 static int __init ifb_init_one(int index)
 {
        struct net_device *dev_ifb;
@@ -264,9 +247,6 @@ static int __init ifb_init_one(int index)
        if (err < 0)
                goto err;
 
-       netdev_for_each_tx_queue(dev_ifb, set_tx_lockdep_key, NULL);
-       lockdep_set_class(&dev_ifb->rx_queue.lock, &ifb_rx_queue_lock_key);
-
        return 0;
 
 err:

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 3170bce..9c5a688 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -443,7 +443,6 @@ enum netdev_queue_state_t
 };
 
 struct netdev_queue {
-       spinlock_t              lock;
        struct net_device       *dev;
        struct Qdisc            *qdisc;
        unsigned long           state;

diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index 1eef8d0..2902a42 100644 (file)
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -163,6 +163,11 @@ struct tcf_proto
        struct tcf_proto_ops    *ops;
 };
 
+static inline spinlock_t *qdisc_lock(struct Qdisc *qdisc)
+{
+       return &qdisc->q.lock;
+}
+
 static inline struct Qdisc *qdisc_root(struct Qdisc *qdisc)
 {
        return qdisc->dev_queue->qdisc;
@@ -172,7 +177,7 @@ static inline spinlock_t *qdisc_root_lock(struct Qdisc *qdisc)
 {
        struct Qdisc *root = qdisc_root(qdisc);
 
-       return &root->dev_queue->lock;
+       return qdisc_lock(root);
 }
 
 static inline struct net_device *qdisc_dev(struct Qdisc *qdisc)

diff --git a/net/core/dev.c b/net/core/dev.c
index 6741e34..32a1377 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2080,10 +2080,12 @@ static int ing_filter(struct sk_buff *skb)
 
        rxq = &dev->rx_queue;
 
-       spin_lock(&rxq->lock);
-       if ((q = rxq->qdisc) != NULL)
+       q = rxq->qdisc;
+       if (q) {
+               spin_lock(qdisc_lock(q));
                result = q->enqueue(skb, q);
-       spin_unlock(&rxq->lock);
+               spin_unlock(qdisc_lock(q));
+       }
 
        return result;
 }
@@ -4173,7 +4175,6 @@ static void netdev_init_one_queue(struct net_device *dev,
                                  struct netdev_queue *queue,
                                  void *_unused)
 {
-       spin_lock_init(&queue->lock);
        queue->dev = dev;
 }
 

diff --git a/net/mac80211/wme.c b/net/mac80211/wme.c
index b21cfec..6e8099e 100644 (file)
--- a/net/mac80211/wme.c
+++ b/net/mac80211/wme.c
@@ -237,12 +237,14 @@ void ieee80211_ht_agg_queue_remove(struct ieee80211_local *local,
                ieee80211_requeue(local, agg_queue);
        } else {
                struct netdev_queue *txq;
+               spinlock_t *root_lock;
 
                txq = netdev_get_tx_queue(local->mdev, agg_queue);
+               root_lock = qdisc_root_lock(txq->qdisc);
 
-               spin_lock_bh(&txq->lock);
+               spin_lock_bh(root_lock);
                qdisc_reset(txq->qdisc);
-               spin_unlock_bh(&txq->lock);
+               spin_unlock_bh(root_lock);
        }
 }
 
@@ -250,6 +252,7 @@ void ieee80211_requeue(struct ieee80211_local *local, int queue)
 {
        struct netdev_queue *txq = netdev_get_tx_queue(local->mdev, queue);
        struct sk_buff_head list;
+       spinlock_t *root_lock;
        struct Qdisc *qdisc;
        u32 len;
 
@@ -261,14 +264,15 @@ void ieee80211_requeue(struct ieee80211_local *local, int queue)
 
        skb_queue_head_init(&list);
 
-       spin_lock(&txq->lock);
+       root_lock = qdisc_root_lock(qdisc);
+       spin_lock(root_lock);
        for (len = qdisc->q.qlen; len > 0; len--) {
                struct sk_buff *skb = qdisc->dequeue(qdisc);
 
                if (skb)
                        __skb_queue_tail(&list, skb);
        }
-       spin_unlock(&txq->lock);
+       spin_unlock(root_lock);
 
        for (len = list.qlen; len > 0; len--) {
                struct sk_buff *skb = __skb_dequeue(&list);
@@ -280,12 +284,13 @@ void ieee80211_requeue(struct ieee80211_local *local, int queue)
 
                txq = netdev_get_tx_queue(local->mdev, new_queue);
 
-               spin_lock(&txq->lock);
 
                qdisc = rcu_dereference(txq->qdisc);
-               qdisc->enqueue(skb, qdisc);
+               root_lock = qdisc_root_lock(qdisc);
 
-               spin_unlock(&txq->lock);
+               spin_lock(root_lock);
+               qdisc->enqueue(skb, qdisc);
+               spin_unlock(root_lock);
        }
 
 out_unlock:

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 3d53e92..8fc580b 100644 (file)
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -96,15 +96,15 @@ static inline int handle_dev_cpu_collision(struct sk_buff *skb,
 }
 
 /*
- * NOTE: Called under queue->lock with locally disabled BH.
+ * NOTE: Called under qdisc_lock(q) with locally disabled BH.
  *
  * __QDISC_STATE_RUNNING guarantees only one CPU can process
- * this qdisc at a time. queue->lock serializes queue accesses for
- * this queue AND txq->qdisc pointer itself.
+ * this qdisc at a time. qdisc_lock(q) serializes queue accesses for
+ * this queue.
  *
  *  netif_tx_lock serializes accesses to device driver.
  *
- *  queue->lock and netif_tx_lock are mutually exclusive,
+ *  qdisc_lock(q) and netif_tx_lock are mutually exclusive,
  *  if one is grabbed, another must be free.
  *
  * Note, that this procedure can be called by a watchdog timer
@@ -317,7 +317,6 @@ struct Qdisc_ops noop_qdisc_ops __read_mostly = {
 };
 
 static struct netdev_queue noop_netdev_queue = {
-       .lock           =       __SPIN_LOCK_UNLOCKED(noop_netdev_queue.lock),
        .qdisc          =       &noop_qdisc,
 };
 
@@ -327,6 +326,7 @@ struct Qdisc noop_qdisc = {
        .flags          =       TCQ_F_BUILTIN,
        .ops            =       &noop_qdisc_ops,
        .list           =       LIST_HEAD_INIT(noop_qdisc.list),
+       .q.lock         =       __SPIN_LOCK_UNLOCKED(noop_qdisc.q.lock),
        .dev_queue      =       &noop_netdev_queue,
 };
 EXPORT_SYMBOL(noop_qdisc);
@@ -498,7 +498,7 @@ errout:
 }
 EXPORT_SYMBOL(qdisc_create_dflt);
 
-/* Under queue->lock and BH! */
+/* Under qdisc_root_lock(qdisc) and BH! */
 
 void qdisc_reset(struct Qdisc *qdisc)
 {
@@ -526,10 +526,12 @@ static void __qdisc_destroy(struct rcu_head *head)
        module_put(ops->owner);
        dev_put(qdisc_dev(qdisc));
 
+       kfree_skb(qdisc->gso_skb);
+
        kfree((char *) qdisc - qdisc->padded);
 }
 
-/* Under queue->lock and BH! */
+/* Under qdisc_root_lock(qdisc) and BH! */
 
 void qdisc_destroy(struct Qdisc *qdisc)
 {
@@ -586,13 +588,12 @@ static void transition_one_qdisc(struct net_device *dev,
                                 struct netdev_queue *dev_queue,
                                 void *_need_watchdog)
 {
+       struct Qdisc *new_qdisc = dev_queue->qdisc_sleeping;
        int *need_watchdog_p = _need_watchdog;
 
-       spin_lock_bh(&dev_queue->lock);
-       rcu_assign_pointer(dev_queue->qdisc, dev_queue->qdisc_sleeping);
-       if (dev_queue->qdisc != &noqueue_qdisc)
+       rcu_assign_pointer(dev_queue->qdisc, new_qdisc);
+       if (new_qdisc != &noqueue_qdisc)
                *need_watchdog_p = 1;
-       spin_unlock_bh(&dev_queue->lock);
 }
 
 void dev_activate(struct net_device *dev)
@@ -629,19 +630,16 @@ static void dev_deactivate_queue(struct net_device *dev,
        struct sk_buff *skb = NULL;
        struct Qdisc *qdisc;
 
-       spin_lock_bh(&dev_queue->lock);
-
        qdisc = dev_queue->qdisc;
        if (qdisc) {
+               spin_lock_bh(qdisc_lock(qdisc));
+
                dev_queue->qdisc = qdisc_default;
                qdisc_reset(qdisc);
 
-               skb = qdisc->gso_skb;
-               qdisc->gso_skb = NULL;
+               spin_unlock_bh(qdisc_lock(qdisc));
        }
 
-       spin_unlock_bh(&dev_queue->lock);
-
        kfree_skb(skb);
 }
 

diff --git a/net/sched/sch_teql.c b/net/sched/sch_teql.c
index ade3372..8b0ff34 100644 (file)
--- a/net/sched/sch_teql.c
+++ b/net/sched/sch_teql.c
@@ -156,12 +156,15 @@ teql_destroy(struct Qdisc* sch)
                                        master->slaves = NEXT_SLAVE(q);
                                        if (q == master->slaves) {
                                                struct netdev_queue *txq;
+                                               spinlock_t *root_lock;
 
                                                txq = netdev_get_tx_queue(master->dev, 0);
                                                master->slaves = NULL;
-                                               spin_lock_bh(&txq->lock);
+
+                                               root_lock = qdisc_root_lock(txq->qdisc);
+                                               spin_lock_bh(root_lock);
                                                qdisc_reset(txq->qdisc);
-                                               spin_unlock_bh(&txq->lock);
+                                               spin_unlock_bh(root_lock);
                                        }
                                }
                                skb_queue_purge(&dat->q);