net: Simplify RX queue allocation

This patch move RX queue allocation to alloc_netdev_mq and freeing of
the queues to free_netdev (symmetric to TX queue allocation).  Each
kobject RX queue takes a reference to the queue's device so that the
device can't be freed before all the kobjects have been released-- this
obviates the need for reference counts specific to RX queues.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 6e4cfbc..fccb11f 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -592,8 +592,7 @@ struct netdev_rx_queue {
        struct rps_map __rcu            *rps_map;
        struct rps_dev_flow_table __rcu *rps_flow_table;
        struct kobject                  kobj;
-       struct netdev_rx_queue          *first;
-       atomic_t                        count;
+       struct net_device               *dev;
 } ____cacheline_aligned_in_smp;
 #endif /* CONFIG_RPS */
 

diff --git a/net/core/dev.c b/net/core/dev.c
index 7549067..8725d16 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5051,12 +5051,8 @@ static int netif_alloc_rx_queues(struct net_device *dev)
        }
        dev->_rx = rx;
 
-       /*
-        * Set a pointer to first element in the array which holds the
-        * reference count.
-        */
        for (i = 0; i < count; i++)
-               rx[i].first = rx;
+               rx[i].dev = dev;
 #endif
        return 0;
 }
@@ -5132,10 +5128,6 @@ int register_netdevice(struct net_device *dev)
 
        dev->iflink = -1;
 
-       ret = netif_alloc_rx_queues(dev);
-       if (ret)
-               goto out;
-
        netdev_init_queues(dev);
 
        /* Init, if this function is available */
@@ -5601,6 +5593,8 @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
 #ifdef CONFIG_RPS
        dev->num_rx_queues = queue_count;
        dev->real_num_rx_queues = queue_count;
+       if (netif_alloc_rx_queues(dev))
+               goto free_pcpu;
 #endif
 
        dev->gso_max_size = GSO_MAX_SIZE;
@@ -5618,6 +5612,10 @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
 free_pcpu:
        free_percpu(dev->pcpu_refcnt);
        kfree(dev->_tx);
+#ifdef CONFIG_RPS
+       kfree(dev->_rx);
+#endif
+
 free_p:
        kfree(p);
        return NULL;
@@ -5639,6 +5637,9 @@ void free_netdev(struct net_device *dev)
        release_net(dev_net(dev));
 
        kfree(dev->_tx);
+#ifdef CONFIG_RPS
+       kfree(dev->_rx);
+#endif
 
        kfree(rcu_dereference_raw(dev->ingress_queue));
 

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index a5ff5a8..3ba526b 100644 (file)
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -706,7 +706,6 @@ static struct attribute *rx_queue_default_attrs[] = {
 static void rx_queue_release(struct kobject *kobj)
 {
        struct netdev_rx_queue *queue = to_rx_queue(kobj);
-       struct netdev_rx_queue *first = queue->first;
        struct rps_map *map;
        struct rps_dev_flow_table *flow_table;
 
@@ -719,8 +718,7 @@ static void rx_queue_release(struct kobject *kobj)
        if (flow_table)
                call_rcu(&flow_table->rcu, rps_dev_flow_table_release);
 
-       if (atomic_dec_and_test(&first->count))
-               kfree(first);
+       dev_put(queue->dev);
 }
 
 static struct kobj_type rx_queue_ktype = {
@@ -732,7 +730,6 @@ static struct kobj_type rx_queue_ktype = {
 static int rx_queue_add_kobject(struct net_device *net, int index)
 {
        struct netdev_rx_queue *queue = net->_rx + index;
-       struct netdev_rx_queue *first = queue->first;
        struct kobject *kobj = &queue->kobj;
        int error = 0;
 
@@ -745,7 +742,7 @@ static int rx_queue_add_kobject(struct net_device *net, int index)
        }
 
        kobject_uevent(kobj, KOBJ_ADD);
-       atomic_inc(&first->count);
+       dev_hold(queue->dev);
 
        return error;
 }