netpoll: Allow netpoll_setup/cleanup recursion

This patch adds the functions __netpoll_setup/__netpoll_cleanup
which is designed to be called recursively through ndo_netpoll_seutp.

They must be called with RTNL held, and the caller must initialise
np->dev and ensure that it has a valid reference count.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h
index 95c9f7e..f3ad74a 100644 (file)
--- a/include/linux/netpoll.h
+++ b/include/linux/netpoll.h
@@ -46,9 +46,11 @@ void netpoll_poll(struct netpoll *np);
 void netpoll_send_udp(struct netpoll *np, const char *msg, int len);
 void netpoll_print_options(struct netpoll *np);
 int netpoll_parse_options(struct netpoll *np, char *opt);
+int __netpoll_setup(struct netpoll *np);
 int netpoll_setup(struct netpoll *np);
 int netpoll_trap(void);
 void netpoll_set_trap(int trap);
+void __netpoll_cleanup(struct netpoll *np);
 void netpoll_cleanup(struct netpoll *np);
 int __netpoll_rx(struct sk_buff *skb);
 void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb);

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 7de6dca..560297e 100644 (file)
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -693,15 +693,78 @@ int netpoll_parse_options(struct netpoll *np, char *opt)
        return -1;
 }
 
-int netpoll_setup(struct netpoll *np)
+int __netpoll_setup(struct netpoll *np)
 {
-       struct net_device *ndev = NULL;
-       struct in_device *in_dev;
+       struct net_device *ndev = np->dev;
        struct netpoll_info *npinfo;
        const struct net_device_ops *ops;
        unsigned long flags;
        int err;
 
+       if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
+           !ndev->netdev_ops->ndo_poll_controller) {
+               printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
+                      np->name, np->dev_name);
+               err = -ENOTSUPP;
+               goto out;
+       }
+
+       if (!ndev->npinfo) {
+               npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
+               if (!npinfo) {
+                       err = -ENOMEM;
+                       goto out;
+               }
+
+               npinfo->rx_flags = 0;
+               INIT_LIST_HEAD(&npinfo->rx_np);
+
+               spin_lock_init(&npinfo->rx_lock);
+               skb_queue_head_init(&npinfo->arp_tx);
+               skb_queue_head_init(&npinfo->txq);
+               INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
+
+               atomic_set(&npinfo->refcnt, 1);
+
+               ops = np->dev->netdev_ops;
+               if (ops->ndo_netpoll_setup) {
+                       err = ops->ndo_netpoll_setup(ndev, npinfo);
+                       if (err)
+                               goto free_npinfo;
+               }
+       } else {
+               npinfo = ndev->npinfo;
+               atomic_inc(&npinfo->refcnt);
+       }
+
+       npinfo->netpoll = np;
+
+       if (np->rx_hook) {
+               spin_lock_irqsave(&npinfo->rx_lock, flags);
+               npinfo->rx_flags |= NETPOLL_RX_ENABLED;
+               list_add_tail(&np->rx, &npinfo->rx_np);
+               spin_unlock_irqrestore(&npinfo->rx_lock, flags);
+       }
+
+       /* last thing to do is link it to the net device structure */
+       rcu_assign_pointer(ndev->npinfo, npinfo);
+       rtnl_unlock();
+
+       return 0;
+
+free_npinfo:
+       kfree(npinfo);
+out:
+       return err;
+}
+EXPORT_SYMBOL_GPL(__netpoll_setup);
+
+int netpoll_setup(struct netpoll *np)
+{
+       struct net_device *ndev = NULL;
+       struct in_device *in_dev;
+       int err;
+
        if (np->dev_name)
                ndev = dev_get_by_name(&init_net, np->dev_name);
        if (!ndev) {
@@ -774,61 +837,14 @@ int netpoll_setup(struct netpoll *np)
        refill_skbs();
 
        rtnl_lock();
-       if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) ||
-           !ndev->netdev_ops->ndo_poll_controller) {
-               printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
-                      np->name, np->dev_name);
-               err = -ENOTSUPP;
-               goto unlock;
-       }
-
-       if (!ndev->npinfo) {
-               npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
-               if (!npinfo) {
-                       err = -ENOMEM;
-                       goto unlock;
-               }
-
-               npinfo->rx_flags = 0;
-               INIT_LIST_HEAD(&npinfo->rx_np);
-
-               spin_lock_init(&npinfo->rx_lock);
-               skb_queue_head_init(&npinfo->arp_tx);
-               skb_queue_head_init(&npinfo->txq);
-               INIT_DELAYED_WORK(&npinfo->tx_work, queue_process);
-
-               atomic_set(&npinfo->refcnt, 1);
-
-               ops = np->dev->netdev_ops;
-               if (ops->ndo_netpoll_setup) {
-                       err = ops->ndo_netpoll_setup(ndev, npinfo);
-                       if (err)
-                               goto free_npinfo;
-               }
-       } else {
-               npinfo = ndev->npinfo;
-               atomic_inc(&npinfo->refcnt);
-       }
-
-       npinfo->netpoll = np;
-
-       if (np->rx_hook) {
-               spin_lock_irqsave(&npinfo->rx_lock, flags);
-               npinfo->rx_flags |= NETPOLL_RX_ENABLED;
-               list_add_tail(&np->rx, &npinfo->rx_np);
-               spin_unlock_irqrestore(&npinfo->rx_lock, flags);
-       }
-
-       /* last thing to do is link it to the net device structure */
-       rcu_assign_pointer(ndev->npinfo, npinfo);
+       err = __netpoll_setup(np);
        rtnl_unlock();
 
+       if (err)
+               goto put;
+
        return 0;
 
-free_npinfo:
-       kfree(npinfo);
-unlock:
-       rtnl_unlock();
 put:
        dev_put(ndev);
        return err;
@@ -841,40 +857,32 @@ static int __init netpoll_init(void)
 }
 core_initcall(netpoll_init);
 
-void netpoll_cleanup(struct netpoll *np)
+void __netpoll_cleanup(struct netpoll *np)
 {
        struct netpoll_info *npinfo;
        unsigned long flags;
-       int free = 0;
 
-       if (!np->dev)
+       npinfo = np->dev->npinfo;
+       if (!npinfo)
                return;
 
-       rtnl_lock();
-       npinfo = np->dev->npinfo;
-       if (npinfo) {
-               if (!list_empty(&npinfo->rx_np)) {
-                       spin_lock_irqsave(&npinfo->rx_lock, flags);
-                       list_del(&np->rx);
-                       if (list_empty(&npinfo->rx_np))
-                               npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
-                       spin_unlock_irqrestore(&npinfo->rx_lock, flags);
-               }
+       if (!list_empty(&npinfo->rx_np)) {
+               spin_lock_irqsave(&npinfo->rx_lock, flags);
+               list_del(&np->rx);
+               if (list_empty(&npinfo->rx_np))
+                       npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
+               spin_unlock_irqrestore(&npinfo->rx_lock, flags);
+       }
 
-               free = atomic_dec_and_test(&npinfo->refcnt);
-               if (free) {
-                       const struct net_device_ops *ops;
+       if (atomic_dec_and_test(&npinfo->refcnt)) {
+               const struct net_device_ops *ops;
 
-                       ops = np->dev->netdev_ops;
-                       if (ops->ndo_netpoll_cleanup)
-                               ops->ndo_netpoll_cleanup(np->dev);
+               ops = np->dev->netdev_ops;
+               if (ops->ndo_netpoll_cleanup)
+                       ops->ndo_netpoll_cleanup(np->dev);
 
-                       rcu_assign_pointer(np->dev->npinfo, NULL);
-               }
-       }
-       rtnl_unlock();
+               rcu_assign_pointer(np->dev->npinfo, NULL);
 
-       if (free) {
                /* avoid racing with NAPI reading npinfo */
                synchronize_rcu_bh();
 
@@ -886,9 +894,19 @@ void netpoll_cleanup(struct netpoll *np)
                __skb_queue_purge(&npinfo->txq);
                kfree(npinfo);
        }
+}
+EXPORT_SYMBOL_GPL(__netpoll_cleanup);
 
-       dev_put(np->dev);
+void netpoll_cleanup(struct netpoll *np)
+{
+       if (!np->dev)
+               return;
 
+       rtnl_lock();
+       __netpoll_cleanup(np);
+       rtnl_unlock();
+
+       dev_put(np->dev);
        np->dev = NULL;
 }