[NET]: Make netdev_chain a raw notifier.

From: Alan Stern <stern@rowland.harvard.edu>

This chain does it's own locking via the RTNL semaphore, and
can also run recursively so adding a new mutex here was causing
deadlocks.

Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -193,7 +193,7 @@ static inline struct hlist_head *dev_index_hash(int ifindex)
  *	Our notifier list
  */
 
-static BLOCKING_NOTIFIER_HEAD(netdev_chain);
+static RAW_NOTIFIER_HEAD(netdev_chain);
 
 /*
  *	Device drivers call our routines to queue packets here. We empty the
@@ -736,7 +736,7 @@ int dev_change_name(struct net_device *dev, char *newname)
 	if (!err) {
 		hlist_del(&dev->name_hlist);
 		hlist_add_head(&dev->name_hlist, dev_name_hash(dev->name));
-		blocking_notifier_call_chain(&netdev_chain,
+		raw_notifier_call_chain(&netdev_chain,
 				NETDEV_CHANGENAME, dev);
 	}
 
@@ -751,7 +751,7 @@ int dev_change_name(struct net_device *dev, char *newname)
  */
 void netdev_features_change(struct net_device *dev)
 {
-	blocking_notifier_call_chain(&netdev_chain, NETDEV_FEAT_CHANGE, dev);
+	raw_notifier_call_chain(&netdev_chain, NETDEV_FEAT_CHANGE, dev);
 }
 EXPORT_SYMBOL(netdev_features_change);
 
@@ -766,7 +766,7 @@ EXPORT_SYMBOL(netdev_features_change);
 void netdev_state_change(struct net_device *dev)
 {
 	if (dev->flags & IFF_UP) {
-		blocking_notifier_call_chain(&netdev_chain,
+		raw_notifier_call_chain(&netdev_chain,
 				NETDEV_CHANGE, dev);
 		rtmsg_ifinfo(RTM_NEWLINK, dev, 0);
 	}
@@ -864,7 +864,7 @@ int dev_open(struct net_device *dev)
 		/*
 		 *	... and announce new interface.
 		 */
-		blocking_notifier_call_chain(&netdev_chain, NETDEV_UP, dev);
+		raw_notifier_call_chain(&netdev_chain, NETDEV_UP, dev);
 	}
 	return ret;
 }
@@ -887,7 +887,7 @@ int dev_close(struct net_device *dev)
 	 *	Tell people we are going down, so that they can
 	 *	prepare to death, when device is still operating.
 	 */
-	blocking_notifier_call_chain(&netdev_chain, NETDEV_GOING_DOWN, dev);
+	raw_notifier_call_chain(&netdev_chain, NETDEV_GOING_DOWN, dev);
 
 	dev_deactivate(dev);
 
@@ -924,7 +924,7 @@ int dev_close(struct net_device *dev)
 	/*
 	 * Tell people we are down
 	 */
-	blocking_notifier_call_chain(&netdev_chain, NETDEV_DOWN, dev);
+	raw_notifier_call_chain(&netdev_chain, NETDEV_DOWN, dev);
 
 	return 0;
 }
@@ -955,7 +955,7 @@ int register_netdevice_notifier(struct notifier_block *nb)
 	int err;
 
 	rtnl_lock();
-	err = blocking_notifier_chain_register(&netdev_chain, nb);
+	err = raw_notifier_chain_register(&netdev_chain, nb);
 	if (!err) {
 		for (dev = dev_base; dev; dev = dev->next) {
 			nb->notifier_call(nb, NETDEV_REGISTER, dev);
@@ -983,7 +983,7 @@ int unregister_netdevice_notifier(struct notifier_block *nb)
 	int err;
 
 	rtnl_lock();
-	err = blocking_notifier_chain_unregister(&netdev_chain, nb);
+	err = raw_notifier_chain_unregister(&netdev_chain, nb);
 	rtnl_unlock();
 	return err;
 }
@@ -994,12 +994,12 @@ int unregister_netdevice_notifier(struct notifier_block *nb)
  *      @v:   pointer passed unmodified to notifier function
  *
  *	Call all network notifier blocks.  Parameters and return value
- *	are as for blocking_notifier_call_chain().
+ *	are as for raw_notifier_call_chain().
  */
 
 int call_netdevice_notifiers(unsigned long val, void *v)
 {
-	return blocking_notifier_call_chain(&netdev_chain, val, v);
+	return raw_notifier_call_chain(&netdev_chain, val, v);
 }
 
 /* When > 0 there are consumers of rx skb time stamps */
@@ -2308,7 +2308,7 @@ int dev_change_flags(struct net_device *dev, unsigned flags)
 	if (dev->flags & IFF_UP &&
 	    ((old_flags ^ dev->flags) &~ (IFF_UP | IFF_PROMISC | IFF_ALLMULTI |
 					  IFF_VOLATILE)))
-		blocking_notifier_call_chain(&netdev_chain,
+		raw_notifier_call_chain(&netdev_chain,
 				NETDEV_CHANGE, dev);
 
 	if ((flags ^ dev->gflags) & IFF_PROMISC) {
@@ -2353,7 +2353,7 @@ int dev_set_mtu(struct net_device *dev, int new_mtu)
 	else
 		dev->mtu = new_mtu;
 	if (!err && dev->flags & IFF_UP)
-		blocking_notifier_call_chain(&netdev_chain,
+		raw_notifier_call_chain(&netdev_chain,
 				NETDEV_CHANGEMTU, dev);
 	return err;
 }
@@ -2370,7 +2370,7 @@ int dev_set_mac_address(struct net_device *dev, struct sockaddr *sa)
 		return -ENODEV;
 	err = dev->set_mac_address(dev, sa);
 	if (!err)
-		blocking_notifier_call_chain(&netdev_chain,
+		raw_notifier_call_chain(&netdev_chain,
 				NETDEV_CHANGEADDR, dev);
 	return err;
 }
@@ -2427,7 +2427,7 @@ static int dev_ifsioc(struct ifreq *ifr, unsigned int cmd)
 				return -EINVAL;
 			memcpy(dev->broadcast, ifr->ifr_hwaddr.sa_data,
 			       min(sizeof ifr->ifr_hwaddr.sa_data, (size_t) dev->addr_len));
-			blocking_notifier_call_chain(&netdev_chain,
+			raw_notifier_call_chain(&netdev_chain,
 					    NETDEV_CHANGEADDR, dev);
 			return 0;
 
@@ -2882,7 +2882,7 @@ int register_netdevice(struct net_device *dev)
 	write_unlock_bh(&dev_base_lock);
 
 	/* Notify protocols, that a new device appeared. */
-	blocking_notifier_call_chain(&netdev_chain, NETDEV_REGISTER, dev);
+	raw_notifier_call_chain(&netdev_chain, NETDEV_REGISTER, dev);
 
 	/* Finish registration after unlock */
 	net_set_todo(dev);
@@ -2961,7 +2961,7 @@ static void netdev_wait_allrefs(struct net_device *dev)
 			rtnl_lock();
 
 			/* Rebroadcast unregister notification */
-			blocking_notifier_call_chain(&netdev_chain,
+			raw_notifier_call_chain(&netdev_chain,
 					    NETDEV_UNREGISTER, dev);
 
 			if (test_bit(__LINK_STATE_LINKWATCH_PENDING,
@@ -3216,7 +3216,7 @@ int unregister_netdevice(struct net_device *dev)
 	/* Notify protocols, that we are about to destroy
 	   this device. They should clean all the things.
 	*/
-	blocking_notifier_call_chain(&netdev_chain, NETDEV_UNREGISTER, dev);
+	raw_notifier_call_chain(&netdev_chain, NETDEV_UNREGISTER, dev);
 	
 	/*
 	 *	Flush the multicast chain