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>

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 14fbb04..880d565 100644 (file)
--- 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 d33adec..4c3ac53 100644 (file)
--- 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: