net: introduce name_node struct to be used in hashlist

Introduce name_node structure to hold name of device and put it into hashlist instead of putting there struct net_device directly. Add a necessary infrastructure to manipulate the hashlist. This prepares the code to use the same hashlist for alternative names introduced later in this set.

Jiri Pirko committed 7 years ago

Commit ff927411 parent 6958c972 files · +87 −20Browse files

Unified · Split

2 files

include/linux/netdevice.h +8 −2
net/core/dev.c +79 −18

include/linux/netdevice.h+8−2

 struct devlink;
 struct tlsdev_ops;
+struct netdev_name_node {
+	struct hlist_node hlist;
+	struct net_device *dev;
+	const char *name;
+};
 /*
  * This structure defines the management hooks for network devices.
  * The following hooks can be defined; unless noted otherwise, they are
  *		(i.e. as seen by users in the "Space.c" file).  It is the name
  *		of the interface.
  *
- *	@name_hlist: 	Device name hash chain, please keep it close to name[]
+ *	@name_node:	Name hashlist node
  *	@ifalias:	SNMP alias
  *	@mem_end:	Shared memory end
  *	@mem_start:	Shared memory start
 struct net_device {
 	char			name[IFNAMSIZ];
-	struct hlist_node	name_hlist;
+	struct netdev_name_node	*name_node;
 	struct dev_ifalias	__rcu *ifalias;
 	/*
 	 *	I/O specific fields

net/core/dev.c+79−18

 #endif
 }
+static struct netdev_name_node *netdev_name_node_alloc(struct net_device *dev,
+						       const char *name)
+{
+	struct netdev_name_node *name_node;
+	name_node = kmalloc(sizeof(*name_node), GFP_KERNEL);
+	if (!name_node)
+		return NULL;
+	INIT_HLIST_NODE(&name_node->hlist);
+	name_node->dev = dev;
+	name_node->name = name;
+	return name_node;
+}
+static struct netdev_name_node *
+netdev_name_node_head_alloc(struct net_device *dev)
+{
+	return netdev_name_node_alloc(dev, dev->name);
+}
+static void netdev_name_node_free(struct netdev_name_node *name_node)
+{
+	kfree(name_node);
+}
+static void netdev_name_node_add(struct net *net,
+				 struct netdev_name_node *name_node)
+{
+	hlist_add_head_rcu(&name_node->hlist,
+			   dev_name_hash(net, name_node->name));
+}
+static void netdev_name_node_del(struct netdev_name_node *name_node)
+{
+	hlist_del_rcu(&name_node->hlist);
+}
+static struct netdev_name_node *netdev_name_node_lookup(struct net *net,
+							const char *name)
+{
+	struct hlist_head *head = dev_name_hash(net, name);
+	struct netdev_name_node *name_node;
+	hlist_for_each_entry(name_node, head, hlist)
+		if (!strcmp(name_node->name, name))
+			return name_node;
+	return NULL;
+}
+static struct netdev_name_node *netdev_name_node_lookup_rcu(struct net *net,
+							    const char *name)
+{
+	struct hlist_head *head = dev_name_hash(net, name);
+	struct netdev_name_node *name_node;
+	hlist_for_each_entry_rcu(name_node, head, hlist)
+		if (!strcmp(name_node->name, name))
+			return name_node;
+	return NULL;
+}
 /* Device list insertion */
 static void list_netdevice(struct net_device *dev)
 {
 	write_lock_bh(&dev_base_lock);
 	list_add_tail_rcu(&dev->dev_list, &net->dev_base_head);
-	hlist_add_head_rcu(&dev->name_hlist, dev_name_hash(net, dev->name));
+	netdev_name_node_add(net, dev->name_node);
 	hlist_add_head_rcu(&dev->index_hlist,
 			   dev_index_hash(net, dev->ifindex));
 	write_unlock_bh(&dev_base_lock);
 	/* Unlink dev from the device chain */
 	write_lock_bh(&dev_base_lock);
 	list_del_rcu(&dev->dev_list);
-	hlist_del_rcu(&dev->name_hlist);
+	netdev_name_node_del(dev->name_node);
 	hlist_del_rcu(&dev->index_hlist);
 	write_unlock_bh(&dev_base_lock);
 struct net_device *__dev_get_by_name(struct net *net, const char *name)
 {
-	struct net_device *dev;
+	struct netdev_name_node *node_name;
-	struct hlist_head *head = dev_name_hash(net, name);
-	hlist_for_each_entry(dev, head, name_hlist)
+	node_name = netdev_name_node_lookup(net, name);
-		if (!strncmp(dev->name, name, IFNAMSIZ))
+	return node_name ? node_name->dev : NULL;
-			return dev;
-	return NULL;
 }
 EXPORT_SYMBOL(__dev_get_by_name);
 struct net_device *dev_get_by_name_rcu(struct net *net, const char *name)
 {
-	struct net_device *dev;
+	struct netdev_name_node *node_name;
-	struct hlist_head *head = dev_name_hash(net, name);
-	hlist_for_each_entry_rcu(dev, head, name_hlist)
-		if (!strncmp(dev->name, name, IFNAMSIZ))
-			return dev;
-	return NULL;
+	node_name = netdev_name_node_lookup_rcu(net, name);
+	return node_name ? node_name->dev : NULL;
 }
 EXPORT_SYMBOL(dev_get_by_name_rcu);
 	netdev_adjacent_rename_links(dev, oldname);
 	write_lock_bh(&dev_base_lock);
-	hlist_del_rcu(&dev->name_hlist);
+	netdev_name_node_del(dev->name_node);
 	write_unlock_bh(&dev_base_lock);
 	synchronize_rcu();
 	write_lock_bh(&dev_base_lock);
-	hlist_add_head_rcu(&dev->name_hlist, dev_name_hash(net, dev->name));
+	netdev_name_node_add(net, dev->name_node);
 	write_unlock_bh(&dev_base_lock);
 	ret = call_netdevice_notifiers(NETDEV_CHANGENAME, dev);
 		dev_uc_flush(dev);
 		dev_mc_flush(dev);
+		netdev_name_node_free(dev->name_node);
 		if (dev->netdev_ops->ndo_uninit)
 			dev->netdev_ops->ndo_uninit(dev);
 	if (ret < 0)
 		goto out;
+	dev->name_node = netdev_name_node_head_alloc(dev);
+	if (!dev->name_node)
+		goto out;
 	/* Init, if this function is available */
 	if (dev->netdev_ops->ndo_init) {
 		ret = dev->netdev_ops->ndo_init(dev);
 	return ret;
 err_uninit:
+	if (dev->name_node)
+		netdev_name_node_free(dev->name_node);
 	if (dev->netdev_ops->ndo_uninit)
 		dev->netdev_ops->ndo_uninit(dev);
 	if (dev->priv_destructor)

net: introduce name_node struct to be used in hashlist

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