netdev: Allocate multiple queues for TX.

alloc_netdev_mq() now allocates an array of netdev_queue
structures for TX, based upon the queue_count argument.

Furthermore, all accesses to the TX queues are now vectored
through the netdev_get_tx_queue() and netdev_for_each_tx_queue()
interfaces.  This makes it easy to grep the tree for all
things that want to get to a TX queue of a net device.

Problem spots which are not really multiqueue aware yet, and
only work with one queue, can easily be spotted by grepping
for all netdev_get_tx_queue() calls that pass in a zero index.

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

2 files changed, 72 insertions, 34 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 570cf7a..f25d4f5 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -463,7 +463,7 @@ struct netdev_queue {
 	struct Qdisc		*qdisc_sleeping;
 	struct list_head	qdisc_list;
 	struct netdev_queue	*next_sched;
-};
+} ____cacheline_aligned_in_smp;
 
 /*
  *	The DEVICE structure.
@@ -641,7 +641,9 @@ struct net_device
 	unsigned char		broadcast[MAX_ADDR_LEN];	/* hw bcast add	*/
 
 	struct netdev_queue	rx_queue;
-	struct netdev_queue	tx_queue ____cacheline_aligned_in_smp;
+
+	struct netdev_queue	*_tx ____cacheline_aligned_in_smp;
+	unsigned int		num_tx_queues;
 	unsigned long		tx_queue_len;	/* Max frames per queue allowed */
 
 /*
@@ -764,6 +766,25 @@ struct net_device
 #define	NETDEV_ALIGN		32
 #define	NETDEV_ALIGN_CONST	(NETDEV_ALIGN - 1)
 
+static inline
+struct netdev_queue *netdev_get_tx_queue(const struct net_device *dev,
+					 unsigned int index)
+{
+	return &dev->_tx[index];
+}
+
+static inline void netdev_for_each_tx_queue(struct net_device *dev,
+					    void (*f)(struct net_device *,
+						      struct netdev_queue *,
+						      void *),
+					    void *arg)
+{
+	unsigned int i;
+
+	for (i = 0; i < dev->num_tx_queues; i++)
+		f(dev, &dev->_tx[i], arg);
+}
+
 /*
  * Net namespace inlines
  */
@@ -977,7 +998,7 @@ static inline void netif_schedule_queue(struct netdev_queue *txq)
 
 static inline void netif_schedule(struct net_device *dev)
 {
-	netif_schedule_queue(&dev->tx_queue);
+	netif_schedule_queue(netdev_get_tx_queue(dev, 0));
 }
 
 /**
@@ -993,7 +1014,7 @@ static inline void netif_tx_start_queue(struct netdev_queue *dev_queue)
 
 static inline void netif_start_queue(struct net_device *dev)
 {
-	netif_tx_start_queue(&dev->tx_queue);
+	netif_tx_start_queue(netdev_get_tx_queue(dev, 0));
 }
 
 /**
@@ -1017,7 +1038,7 @@ static inline void netif_tx_wake_queue(struct netdev_queue *dev_queue)
 
 static inline void netif_wake_queue(struct net_device *dev)
 {
-	netif_tx_wake_queue(&dev->tx_queue);
+	netif_tx_wake_queue(netdev_get_tx_queue(dev, 0));
 }
 
 /**
@@ -1034,7 +1055,7 @@ static inline void netif_tx_stop_queue(struct netdev_queue *dev_queue)
 
 static inline void netif_stop_queue(struct net_device *dev)
 {
-	netif_tx_stop_queue(&dev->tx_queue);
+	netif_tx_stop_queue(netdev_get_tx_queue(dev, 0));
 }
 
 /**
@@ -1050,7 +1071,7 @@ static inline int netif_tx_queue_stopped(const struct netdev_queue *dev_queue)
 
 static inline int netif_queue_stopped(const struct net_device *dev)
 {
-	return netif_tx_queue_stopped(&dev->tx_queue);
+	return netif_tx_queue_stopped(netdev_get_tx_queue(dev, 0));
 }
 
 /**
@@ -1134,7 +1155,7 @@ static inline void netif_wake_subqueue(struct net_device *dev, u16 queue_index)
 #endif
 	if (test_and_clear_bit(__QUEUE_STATE_XOFF,
 			       &dev->egress_subqueue[queue_index].state))
-		__netif_schedule(&dev->tx_queue);
+		__netif_schedule(netdev_get_tx_queue(dev, 0));
 }
 
 /**
@@ -1430,18 +1451,19 @@ static inline void __netif_tx_lock(struct netdev_queue *txq, int cpu)
 
 static inline void netif_tx_lock(struct net_device *dev)
 {
-	__netif_tx_lock(&dev->tx_queue, smp_processor_id());
-}
+	int cpu = smp_processor_id();
+	unsigned int i;
 
-static inline void __netif_tx_lock_bh(struct netdev_queue *txq)
-{
-	spin_lock_bh(&txq->_xmit_lock);
-	txq->xmit_lock_owner = smp_processor_id();
+	for (i = 0; i < dev->num_tx_queues; i++) {
+		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
+		__netif_tx_lock(txq, cpu);
+	}
 }
 
 static inline void netif_tx_lock_bh(struct net_device *dev)
 {
-	__netif_tx_lock_bh(&dev->tx_queue);
+	local_bh_disable();
+	netif_tx_lock(dev);
 }
 
 static inline int __netif_tx_trylock(struct netdev_queue *txq)
@@ -1454,7 +1476,7 @@ static inline int __netif_tx_trylock(struct netdev_queue *txq)
 
 static inline int netif_tx_trylock(struct net_device *dev)
 {
-	return __netif_tx_trylock(&dev->tx_queue);
+	return __netif_tx_trylock(netdev_get_tx_queue(dev, 0));
 }
 
 static inline void __netif_tx_unlock(struct netdev_queue *txq)
@@ -1465,18 +1487,19 @@ static inline void __netif_tx_unlock(struct netdev_queue *txq)
 
 static inline void netif_tx_unlock(struct net_device *dev)
 {
-	__netif_tx_unlock(&dev->tx_queue);
-}
+	unsigned int i;
+
+	for (i = 0; i < dev->num_tx_queues; i++) {
+		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
+		__netif_tx_unlock(txq);
+	}
 
-static inline void __netif_tx_unlock_bh(struct netdev_queue *txq)
-{
-	txq->xmit_lock_owner = -1;
-	spin_unlock_bh(&txq->_xmit_lock);
 }
 
 static inline void netif_tx_unlock_bh(struct net_device *dev)
 {
-	__netif_tx_unlock_bh(&dev->tx_queue);
+	netif_tx_unlock(dev);
+	local_bh_enable();
 }
 
 #define HARD_TX_LOCK(dev, txq, cpu) {			\
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index 5ba66b5..b47f556 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -230,32 +230,47 @@ extern void tcf_destroy_chain(struct tcf_proto **fl);
 /* Reset all TX qdiscs of a device.  */
 static inline void qdisc_reset_all_tx(struct net_device *dev)
 {
-	qdisc_reset(dev->tx_queue.qdisc);
+	unsigned int i;
+	for (i = 0; i < dev->num_tx_queues; i++)
+		qdisc_reset(netdev_get_tx_queue(dev, i)->qdisc);
 }
 
 /* Are all TX queues of the device empty?  */
 static inline bool qdisc_all_tx_empty(const struct net_device *dev)
 {
-	const struct netdev_queue *txq = &dev->tx_queue;
-	const struct Qdisc *q = txq->qdisc;
+	unsigned int i;
+	for (i = 0; i < dev->num_tx_queues; i++) {
+		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
+		const struct Qdisc *q = txq->qdisc;
 
-	return (q->q.qlen == 0);
+		if (q->q.qlen)
+			return false;
+	}
+	return true;
 }
 
 /* Are any of the TX qdiscs changing?  */
 static inline bool qdisc_tx_changing(struct net_device *dev)
 {
-	struct netdev_queue *txq = &dev->tx_queue;
-
-	return (txq->qdisc != txq->qdisc_sleeping);
+	unsigned int i;
+	for (i = 0; i < dev->num_tx_queues; i++) {
+		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
+		if (txq->qdisc != txq->qdisc_sleeping)
+			return true;
+	}
+	return false;
 }
 
-/* Is the device using the noop qdisc?  */
+/* Is the device using the noop qdisc on all queues?  */
 static inline bool qdisc_tx_is_noop(const struct net_device *dev)
 {
-	const struct netdev_queue *txq = &dev->tx_queue;
-
-	return (txq->qdisc == &noop_qdisc);
+	unsigned int i;
+	for (i = 0; i < dev->num_tx_queues; i++) {
+		struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
+		if (txq->qdisc != &noop_qdisc)
+			return false;
+	}
+	return true;
 }
 
 static inline int __qdisc_enqueue_tail(struct sk_buff *skb, struct Qdisc *sch,