diff options
| -rw-r--r-- | include/linux/netdevice.h | 1 | ||||
| -rw-r--r-- | net/core/dev.c | 49 |
2 files changed, 41 insertions, 9 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index e5ece8dceaad..bcf1083857fc 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1115,6 +1115,7 @@ extern void __dev_remove_pack(struct packet_type *pt); extern struct net_device *dev_get_by_flags(struct net *net, unsigned short flags, unsigned short mask); extern struct net_device *dev_get_by_name(struct net *net, const char *name); +extern struct net_device *dev_get_by_name_rcu(struct net *net, const char *name); extern struct net_device *__dev_get_by_name(struct net *net, const char *name); extern int dev_alloc_name(struct net_device *dev, const char *name); extern int dev_open(struct net_device *dev); diff --git a/net/core/dev.c b/net/core/dev.c index 94f42a15fff1..f54d8b8a434b 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -213,7 +213,7 @@ static int list_netdevice(struct net_device *dev) write_lock_bh(&dev_base_lock); list_add_tail(&dev->dev_list, &net->dev_base_head); - hlist_add_head(&dev->name_hlist, dev_name_hash(net, dev->name)); + hlist_add_head_rcu(&dev->name_hlist, dev_name_hash(net, dev->name)); hlist_add_head_rcu(&dev->index_hlist, dev_index_hash(net, dev->ifindex)); write_unlock_bh(&dev_base_lock); @@ -230,7 +230,7 @@ static void unlist_netdevice(struct net_device *dev) /* Unlink dev from the device chain */ write_lock_bh(&dev_base_lock); list_del(&dev->dev_list); - hlist_del(&dev->name_hlist); + hlist_del_rcu(&dev->name_hlist); hlist_del_rcu(&dev->index_hlist); write_unlock_bh(&dev_base_lock); } @@ -599,6 +599,32 @@ struct net_device *__dev_get_by_name(struct net *net, const char *name) EXPORT_SYMBOL(__dev_get_by_name); /** + * dev_get_by_name_rcu - find a device by its name + * @net: the applicable net namespace + * @name: name to find + * + * Find an interface by name. + * If the name is found a pointer to the device is returned. + * If the name is not found then %NULL is returned. + * The reference counters are not incremented so the caller must be + * careful with locks. The caller must hold RCU lock. + */ + +struct net_device *dev_get_by_name_rcu(struct net *net, const char *name) +{ + struct hlist_node *p; + struct net_device *dev; + struct hlist_head *head = dev_name_hash(net, name); + + hlist_for_each_entry_rcu(dev, p, head, name_hlist) + if (!strncmp(dev->name, name, IFNAMSIZ)) + return dev; + + return NULL; +} +EXPORT_SYMBOL(dev_get_by_name_rcu); + +/** * dev_get_by_name - find a device by its name * @net: the applicable net namespace * @name: name to find @@ -614,11 +640,11 @@ struct net_device *dev_get_by_name(struct net *net, const char *name) { struct net_device *dev; - read_lock(&dev_base_lock); - dev = __dev_get_by_name(net, name); + rcu_read_lock(); + dev = dev_get_by_name_rcu(net, name); if (dev) dev_hold(dev); - read_unlock(&dev_base_lock); + rcu_read_unlock(); return dev; } EXPORT_SYMBOL(dev_get_by_name); @@ -960,7 +986,12 @@ rollback: write_lock_bh(&dev_base_lock); hlist_del(&dev->name_hlist); - hlist_add_head(&dev->name_hlist, dev_name_hash(net, dev->name)); + 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)); write_unlock_bh(&dev_base_lock); ret = call_netdevice_notifiers(NETDEV_CHANGENAME, dev); @@ -1062,9 +1093,9 @@ void dev_load(struct net *net, const char *name) { struct net_device *dev; - read_lock(&dev_base_lock); - dev = __dev_get_by_name(net, name); - read_unlock(&dev_base_lock); + rcu_read_lock(); + dev = dev_get_by_name_rcu(net, name); + rcu_read_unlock(); if (!dev && capable(CAP_NET_ADMIN)) request_module("%s", name); |