Re: [PATCH 3/3 v2] 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 <redacted>
---
 include/linux/netdevice.h |    4 +-
 net/core/dev.c            |  106 ++++++++++++++++++++++----------------------
 2 files changed, 55 insertions(+), 55 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 14fbb04..880d565 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 d33adec..7ae5c7e 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;