net: percpu net_device refcount

[net-next-2.6.git] / net / core / dev.c

diff --git a/net/core/dev.c b/net/core/dev.c
index 193eafaabd8867197903909e92cd956da95b5bc4..04972a4783e2e9b75c54fd5c8e30bfedcf674ecc 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5192,9 +5192,6 @@ int init_dummy_netdev(struct net_device *dev)
         */
        dev->reg_state = NETREG_DUMMY;
 
-       /* initialize the ref count */
-       atomic_set(&dev->refcnt, 1);
-
        /* NAPI wants this */
        INIT_LIST_HEAD(&dev->napi_list);
 
@@ -5202,6 +5199,11 @@ int init_dummy_netdev(struct net_device *dev)
        set_bit(__LINK_STATE_PRESENT, &dev->state);
        set_bit(__LINK_STATE_START, &dev->state);
 
+       /* Note : We dont allocate pcpu_refcnt for dummy devices,
+        * because users of this 'device' dont need to change
+        * its refcount.
+        */
+
        return 0;
 }
 EXPORT_SYMBOL_GPL(init_dummy_netdev);
@@ -5243,6 +5245,16 @@ out:
 }
 EXPORT_SYMBOL(register_netdev);
 
+int netdev_refcnt_read(const struct net_device *dev)
+{
+       int i, refcnt = 0;
+
+       for_each_possible_cpu(i)
+               refcnt += *per_cpu_ptr(dev->pcpu_refcnt, i);
+       return refcnt;
+}
+EXPORT_SYMBOL(netdev_refcnt_read);
+
 /*
  * netdev_wait_allrefs - wait until all references are gone.
  *
@@ -5257,11 +5269,14 @@ EXPORT_SYMBOL(register_netdev);
 static void netdev_wait_allrefs(struct net_device *dev)
 {
        unsigned long rebroadcast_time, warning_time;
+       int refcnt;
 
        linkwatch_forget_dev(dev);
 
        rebroadcast_time = warning_time = jiffies;
-       while (atomic_read(&dev->refcnt) != 0) {
+       refcnt = netdev_refcnt_read(dev);
+
+       while (refcnt != 0) {
                if (time_after(jiffies, rebroadcast_time + 1 * HZ)) {
                        rtnl_lock();
 
@@ -5288,11 +5303,13 @@ static void netdev_wait_allrefs(struct net_device *dev)
 
                msleep(250);
 
+               refcnt = netdev_refcnt_read(dev);
+
                if (time_after(jiffies, warning_time + 10 * HZ)) {
                        printk(KERN_EMERG "unregister_netdevice: "
                               "waiting for %s to become free. Usage "
                               "count = %d\n",
-                              dev->name, atomic_read(&dev->refcnt));
+                              dev->name, refcnt);
                        warning_time = jiffies;
                }
        }
@@ -5350,7 +5367,7 @@ void netdev_run_todo(void)
                netdev_wait_allrefs(dev);
 
                /* paranoia */
-               BUG_ON(atomic_read(&dev->refcnt));
+               BUG_ON(netdev_refcnt_read(dev));
                WARN_ON(rcu_dereference_raw(dev->ip_ptr));
                WARN_ON(dev->ip6_ptr);
                WARN_ON(dev->dn_ptr);
@@ -5520,9 +5537,13 @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
        dev = PTR_ALIGN(p, NETDEV_ALIGN);
        dev->padded = (char *)dev - (char *)p;
 
-       if (dev_addr_init(dev))
+       dev->pcpu_refcnt = alloc_percpu(int);
+       if (!dev->pcpu_refcnt)
                goto free_tx;
 
+       if (dev_addr_init(dev))
+               goto free_pcpu;
+
        dev_mc_init(dev);
        dev_uc_init(dev);
 
@@ -5553,6 +5574,8 @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
 
 free_tx:
        kfree(tx);
+free_pcpu:
+       free_percpu(dev->pcpu_refcnt);
 free_p:
        kfree(p);
        return NULL;
@@ -5586,6 +5609,9 @@ void free_netdev(struct net_device *dev)
        list_for_each_entry_safe(p, n, &dev->napi_list, dev_list)
                netif_napi_del(p);
 
+       free_percpu(dev->pcpu_refcnt);
+       dev->pcpu_refcnt = NULL;
+
        /*  Compatibility with error handling in drivers */
        if (dev->reg_state == NETREG_UNINITIALIZED) {
                kfree((char *)dev - dev->padded);