net: allocate tx queues in register_netdevice

This patch introduces netif_alloc_netdev_queues which is called from
register_device instead of alloc_netdev_mq.  This makes TX queue
allocation symmetric with RX allocation.  Also, queue locks allocation
is done in netdev_init_one_queue.  Change set_real_num_tx_queues to
fail if requested number < 1 or greater than number of allocated
queues.

Signed-off-by: Tom Herbert <therbert@google.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 55 insertions, 55 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 14fbb04c459d..880d56565828 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1696,8 +1696,8 @@ static inline int netif_is_multiqueue(const struct net_device *dev)
         return dev->num_tx_queues > 1;
 }
 
-extern void netif_set_real_num_tx_queues(struct net_device *dev,
-                                         unsigned int txq);
+extern int netif_set_real_num_tx_queues(struct net_device *dev,
+                                        unsigned int txq);
 
 #ifdef CONFIG_RPS
 extern int netif_set_real_num_rx_queues(struct net_device *dev,
diff --git a/net/core/dev.c b/net/core/dev.c
index d33adecec44b..4c3ac53e4b16 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1553,18 +1553,20 @@ static void dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev)
  * Routine to help set real_num_tx_queues. To avoid skbs mapped to queues
  * greater then real_num_tx_queues stale skbs on the qdisc must be flushed.
  */
-void netif_set_real_num_tx_queues(struct net_device *dev, unsigned int txq)
+int netif_set_real_num_tx_queues(struct net_device *dev, unsigned int txq)
 {
-        unsigned int real_num = dev->real_num_tx_queues;
+        if (txq < 1 || txq > dev->num_tx_queues)
+                return -EINVAL;
 
-        if (unlikely(txq > dev->num_tx_queues))
-                ;
-        else if (txq > real_num)
-                dev->real_num_tx_queues = txq;
-        else if (txq < real_num) {
-                dev->real_num_tx_queues = txq;
-                qdisc_reset_all_tx_gt(dev, txq);
+        if (dev->reg_state == NETREG_REGISTERED) {
+                ASSERT_RTNL();
+
+                if (txq < dev->real_num_tx_queues)
+                        qdisc_reset_all_tx_gt(dev, txq);
         }
+
+        dev->real_num_tx_queues = txq;
+        return 0;
 }
 EXPORT_SYMBOL(netif_set_real_num_tx_queues);
 
@@ -4928,20 +4930,6 @@ static void rollback_registered(struct net_device *dev)
         rollback_registered_many(&single);
 }
 
-static void __netdev_init_queue_locks_one(struct net_device *dev,
-                                          struct netdev_queue *dev_queue,
-                                          void *_unused)
-{
-        spin_lock_init(&dev_queue->_xmit_lock);
-        netdev_set_xmit_lockdep_class(&dev_queue->_xmit_lock, dev->type);
-        dev_queue->xmit_lock_owner = -1;
-}
-
-static void netdev_init_queue_locks(struct net_device *dev)
-{
-        netdev_for_each_tx_queue(dev, __netdev_init_queue_locks_one, NULL);
-}
-
 unsigned long netdev_fix_features(unsigned long features, const char *name)
 {
         /* Fix illegal SG+CSUM combinations. */
@@ -5034,6 +5022,41 @@ static int netif_alloc_rx_queues(struct net_device *dev)
         return 0;
 }
 
+static int netif_alloc_netdev_queues(struct net_device *dev)
+{
+        unsigned int count = dev->num_tx_queues;
+        struct netdev_queue *tx;
+
+        BUG_ON(count < 1);
+
+        tx = kcalloc(count, sizeof(struct netdev_queue), GFP_KERNEL);
+        if (!tx) {
+                pr_err("netdev: Unable to allocate %u tx queues.\n",
+                       count);
+                return -ENOMEM;
+        }
+        dev->_tx = tx;
+        return 0;
+}
+
+static void netdev_init_one_queue(struct net_device *dev,
+                                  struct netdev_queue *queue,
+                                  void *_unused)
+{
+        queue->dev = dev;
+
+        /* Initialize queue lock */
+        spin_lock_init(&queue->_xmit_lock);
+        netdev_set_xmit_lockdep_class(&queue->_xmit_lock, dev->type);
+        queue->xmit_lock_owner = -1;
+}
+
+static void netdev_init_queues(struct net_device *dev)
+{
+        netdev_for_each_tx_queue(dev, netdev_init_one_queue, NULL);
+        spin_lock_init(&dev->tx_global_lock);
+}
+
 /**
  *      register_netdevice      - register a network device
  *      @dev: device to register
@@ -5067,7 +5090,6 @@ int register_netdevice(struct net_device *dev)
 
         spin_lock_init(&dev->addr_list_lock);
         netdev_set_addr_lockdep_class(dev);
-        netdev_init_queue_locks(dev);
 
         dev->iflink = -1;
 
@@ -5075,6 +5097,12 @@ int register_netdevice(struct net_device *dev)
         if (ret)
                 goto out;
 
+        ret = netif_alloc_netdev_queues(dev);
+        if (ret)
+                goto out;
+
+        netdev_init_queues(dev);
+
         /* Init, if this function is available */
         if (dev->netdev_ops->ndo_init) {
                 ret = dev->netdev_ops->ndo_init(dev);
@@ -5456,19 +5484,6 @@ struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev,
 }
 EXPORT_SYMBOL(dev_get_stats);
 
-static void netdev_init_one_queue(struct net_device *dev,
-                                  struct netdev_queue *queue,
-                                  void *_unused)
-{
-        queue->dev = dev;
-}
-
-static void netdev_init_queues(struct net_device *dev)
-{
-        netdev_for_each_tx_queue(dev, netdev_init_one_queue, NULL);
-        spin_lock_init(&dev->tx_global_lock);
-}
-
 struct netdev_queue *dev_ingress_queue_create(struct net_device *dev)
 {
         struct netdev_queue *queue = dev_ingress_queue(dev);
@@ -5480,7 +5495,6 @@ struct netdev_queue *dev_ingress_queue_create(struct net_device *dev)
         if (!queue)
                 return NULL;
         netdev_init_one_queue(dev, queue, NULL);
-        __netdev_init_queue_locks_one(dev, queue, NULL);
         queue->qdisc = &noop_qdisc;
         queue->qdisc_sleeping = &noop_qdisc;
         rcu_assign_pointer(dev->ingress_queue, queue);
@@ -5502,7 +5516,6 @@ struct netdev_queue *dev_ingress_queue_create(struct net_device *dev)
 struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
                 void (*setup)(struct net_device *), unsigned int queue_count)
 {
-        struct netdev_queue *tx;
         struct net_device *dev;
         size_t alloc_size;
         struct net_device *p;
@@ -5530,20 +5543,12 @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
                 return NULL;
         }
 
-        tx = kcalloc(queue_count, sizeof(struct netdev_queue), GFP_KERNEL);
-        if (!tx) {
-                printk(KERN_ERR "alloc_netdev: Unable to allocate "
-                       "tx qdiscs.\n");
-                goto free_p;
-        }
-
-
         dev = PTR_ALIGN(p, NETDEV_ALIGN);
         dev->padded = (char *)dev - (char *)p;
 
         dev->pcpu_refcnt = alloc_percpu(int);
         if (!dev->pcpu_refcnt)
-                goto free_tx;
+                goto free_p;
 
         if (dev_addr_init(dev))
                 goto free_pcpu;
@@ -5553,7 +5558,6 @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
 
         dev_net_set(dev, &init_net);
 
-        dev->_tx = tx;
         dev->num_tx_queues = queue_count;
         dev->real_num_tx_queues = queue_count;
 
@@ -5564,8 +5568,6 @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
 
         dev->gso_max_size = GSO_MAX_SIZE;
 
-        netdev_init_queues(dev);
-
         INIT_LIST_HEAD(&dev->ethtool_ntuple_list.list);
         dev->ethtool_ntuple_list.count = 0;
         INIT_LIST_HEAD(&dev->napi_list);
@@ -5576,8 +5578,6 @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
         strcpy(dev->name, name);
         return dev;
 
-free_tx:
-        kfree(tx);
 free_pcpu:
         free_percpu(dev->pcpu_refcnt);
 free_p: