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>

1 files changed, 46 insertions, 23 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 570cf7affa72..f25d4f5a31b0 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) {                   \