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.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 9eda1c3..e92bc54 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -925,6 +925,12 @@ struct dev_ifalias {
 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
@@ -1564,7 +1570,7 @@ enum netdev_priv_flags {
  *             (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
@@ -1774,7 +1780,7 @@ enum netdev_priv_flags {
 
 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

diff --git a/net/core/dev.c b/net/core/dev.c
index 21a9c29..d2053d0 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -228,6 +228,67 @@ static inline void rps_unlock(struct softnet_data *sd)
 #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)
 {
@@ -237,7 +298,7 @@ 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);
@@ -255,7 +316,7 @@ static void unlist_netdevice(struct net_device *dev)
        /* 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);
 
@@ -733,14 +794,10 @@ EXPORT_SYMBOL_GPL(dev_fill_metadata_dst);
 
 struct net_device *__dev_get_by_name(struct net *net, const char *name)
 {
-       struct net_device *dev;
-       struct hlist_head *head = dev_name_hash(net, name);
+       struct netdev_name_node *node_name;
 
-       hlist_for_each_entry(dev, head, name_hlist)
-               if (!strncmp(dev->name, name, IFNAMSIZ))
-                       return dev;
-
-       return NULL;
+       node_name = netdev_name_node_lookup(net, name);
+       return node_name ? node_name->dev : NULL;
 }
 EXPORT_SYMBOL(__dev_get_by_name);
 
@@ -758,14 +815,10 @@ 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 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;
+       struct netdev_name_node *node_name;
 
-       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);
 
@@ -1232,13 +1285,13 @@ rollback:
        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);
@@ -8264,6 +8317,8 @@ static void rollback_registered_many(struct list_head *head)
                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);
 
@@ -8706,6 +8761,10 @@ int register_netdevice(struct net_device *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);
@@ -8827,6 +8886,8 @@ out:
        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)