rps: allocate rx queues in register_netdevice only

Instead of having two places were we allocate dev->_rx, introduce
netif_alloc_rx_queues() helper and call it only from
register_netdevice(), not from alloc_netdev_mq()

Goal is to let drivers change dev->num_rx_queues after allocating netdev
and before registering it.

This also removes a lot of ifdefs in net/core/dev.c

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

1 files changed, 32 insertions, 44 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index e0c0b86f57a1..72e99835e5b8 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4964,6 +4964,34 @@ void netif_stacked_transfer_operstate(const struct net_device *rootdev,
 }
 EXPORT_SYMBOL(netif_stacked_transfer_operstate);
 
+static int netif_alloc_rx_queues(struct net_device *dev)
+{
+#ifdef CONFIG_RPS
+        unsigned int i, count = dev->num_rx_queues;
+
+        if (count) {
+                struct netdev_rx_queue *rx;
+
+                rx = kcalloc(count, sizeof(struct netdev_rx_queue), GFP_KERNEL);
+                if (!rx) {
+                        pr_err("netdev: Unable to allocate %u rx queues.\n",
+                               count);
+                        return -ENOMEM;
+                }
+                dev->_rx = rx;
+                atomic_set(&rx->count, count);
+
+                /*
+                 * Set a pointer to first element in the array which holds the
+                 * reference count.
+                 */
+                for (i = 0; i < count; i++)
+                        rx[i].first = rx;
+        }
+#endif
+        return 0;
+}
+
 /**
  *      register_netdevice      - register a network device
  *      @dev: device to register
@@ -5001,24 +5029,10 @@ int register_netdevice(struct net_device *dev)
 
         dev->iflink = -1;
 
-#ifdef CONFIG_RPS
-        if (!dev->num_rx_queues) {
-                /*
-                 * Allocate a single RX queue if driver never called
-                 * alloc_netdev_mq
-                 */
-
-                dev->_rx = kzalloc(sizeof(struct netdev_rx_queue), GFP_KERNEL);
-                if (!dev->_rx) {
-                        ret = -ENOMEM;
-                        goto out;
-                }
+        ret = netif_alloc_rx_queues(dev);
+        if (ret)
+                goto out;
 
-                dev->_rx->first = dev->_rx;
-                atomic_set(&dev->_rx->count, 1);
-                dev->num_rx_queues = 1;
-        }
-#endif
         /* Init, if this function is available */
         if (dev->netdev_ops->ndo_init) {
                 ret = dev->netdev_ops->ndo_init(dev);
@@ -5415,10 +5429,6 @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
         struct net_device *dev;
         size_t alloc_size;
         struct net_device *p;
-#ifdef CONFIG_RPS
-        struct netdev_rx_queue *rx;
-        int i;
-#endif
 
         BUG_ON(strlen(name) >= sizeof(dev->name));
 
@@ -5444,29 +5454,12 @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
                 goto free_p;
         }
 
-#ifdef CONFIG_RPS
-        rx = kcalloc(queue_count, sizeof(struct netdev_rx_queue), GFP_KERNEL);
-        if (!rx) {
-                printk(KERN_ERR "alloc_netdev: Unable to allocate "
-                       "rx queues.\n");
-                goto free_tx;
-        }
-
-        atomic_set(&rx->count, queue_count);
-
-        /*
-         * Set a pointer to first element in the array which holds the
-         * reference count.
-         */
-        for (i = 0; i < queue_count; i++)
-                rx[i].first = rx;
-#endif
 
         dev = PTR_ALIGN(p, NETDEV_ALIGN);
         dev->padded = (char *)dev - (char *)p;
 
         if (dev_addr_init(dev))
-                goto free_rx;
+                goto free_tx;
 
         dev_mc_init(dev);
         dev_uc_init(dev);
@@ -5478,7 +5471,6 @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
         dev->real_num_tx_queues = queue_count;
 
 #ifdef CONFIG_RPS
-        dev->_rx = rx;
         dev->num_rx_queues = queue_count;
 #endif
 
@@ -5496,11 +5488,7 @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
         strcpy(dev->name, name);
         return dev;
 
-free_rx:
-#ifdef CONFIG_RPS
-        kfree(rx);
 free_tx:
-#endif
         kfree(tx);
 free_p:
         kfree(p);