netdev: Fix lockdep warnings in multiqueue configurations.

When support for multiple TX queues were added, the
netif_tx_lock() routines we converted to iterate over
all TX queues and grab each queue's spinlock.

This causes heartburn for lockdep and it's not a healthy
thing to do with lots of TX queues anyways.

So modify this to use a top-level lock and a "frozen"
state for the individual TX queues.

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

5 files changed, 16 insertions, 8 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 63d6bcddbf46..69320a56a084 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4200,6 +4200,7 @@ static void netdev_init_queues(struct net_device *dev)
 {
         netdev_init_one_queue(dev, &dev->rx_queue, NULL);
         netdev_for_each_tx_queue(dev, netdev_init_one_queue, NULL);
+        spin_lock_init(&dev->tx_global_lock);
 }
 
 /**
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index c12720895ecf..6c7af390be0a 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -70,6 +70,7 @@ static void queue_process(struct work_struct *work)
                 local_irq_save(flags);
                 __netif_tx_lock(txq, smp_processor_id());
                 if (netif_tx_queue_stopped(txq) ||
+                    netif_tx_queue_frozen(txq) ||
                     dev->hard_start_xmit(skb, dev) != NETDEV_TX_OK) {
                         skb_queue_head(&npinfo->txq, skb);
                         __netif_tx_unlock(txq);
diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index c7d484f7e1c4..3284605f2ec7 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -3305,6 +3305,7 @@ static __inline__ void pktgen_xmit(struct pktgen_dev *pkt_dev)
 
         txq = netdev_get_tx_queue(odev, queue_map);
         if (netif_tx_queue_stopped(txq) ||
+            netif_tx_queue_frozen(txq) ||
             need_resched()) {
                 idle_start = getCurUs();
 
@@ -3320,7 +3321,8 @@ static __inline__ void pktgen_xmit(struct pktgen_dev *pkt_dev)
 
                 pkt_dev->idle_acc += getCurUs() - idle_start;
 
-                if (netif_tx_queue_stopped(txq)) {
+                if (netif_tx_queue_stopped(txq) ||
+                    netif_tx_queue_frozen(txq)) {
                         pkt_dev->next_tx_us = getCurUs();       /* TODO */
                         pkt_dev->next_tx_ns = 0;
                         goto out;       /* Try the next interface */
@@ -3352,7 +3354,8 @@ static __inline__ void pktgen_xmit(struct pktgen_dev *pkt_dev)
         txq = netdev_get_tx_queue(odev, queue_map);
 
         __netif_tx_lock_bh(txq);
-        if (!netif_tx_queue_stopped(txq)) {
+        if (!netif_tx_queue_stopped(txq) &&
+            !netif_tx_queue_frozen(txq)) {
 
                 atomic_inc(&(pkt_dev->skb->users));
               retry_now:
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 345838a2e369..9c9cd4d94890 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -135,7 +135,8 @@ static inline int qdisc_restart(struct Qdisc *q)
         txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
 
         HARD_TX_LOCK(dev, txq, smp_processor_id());
-        if (!netif_subqueue_stopped(dev, skb))
+        if (!netif_tx_queue_stopped(txq) &&
+            !netif_tx_queue_frozen(txq))
                 ret = dev_hard_start_xmit(skb, dev, txq);
         HARD_TX_UNLOCK(dev, txq);
 
@@ -162,7 +163,8 @@ static inline int qdisc_restart(struct Qdisc *q)
                 break;
         }
 
-        if (ret && netif_tx_queue_stopped(txq))
+        if (ret && (netif_tx_queue_stopped(txq) ||
+                    netif_tx_queue_frozen(txq)))
                 ret = 0;
 
         return ret;
diff --git a/net/sched/sch_teql.c b/net/sched/sch_teql.c
index 537223642b6e..2c35c678563b 100644
--- a/net/sched/sch_teql.c
+++ b/net/sched/sch_teql.c
@@ -305,10 +305,11 @@ restart:
 
                 switch (teql_resolve(skb, skb_res, slave)) {
                 case 0:
-                        if (netif_tx_trylock(slave)) {
-                                if (!__netif_subqueue_stopped(slave, subq) &&
+                        if (__netif_tx_trylock(slave_txq)) {
+                                if (!netif_tx_queue_stopped(slave_txq) &&
+                                    !netif_tx_queue_frozen(slave_txq) &&
                                     slave->hard_start_xmit(skb, slave) == 0) {
-                                        netif_tx_unlock(slave);
+                                        __netif_tx_unlock(slave_txq);
                                         master->slaves = NEXT_SLAVE(q);
                                         netif_wake_queue(dev);
                                         master->stats.tx_packets++;
@@ -316,7 +317,7 @@ restart:
                                                 qdisc_pkt_len(skb);
                                         return 0;
                                 }
-                                netif_tx_unlock(slave);
+                                __netif_tx_unlock(slave_txq);
                         }
                         if (netif_queue_stopped(dev))
                                 busy = 1;