@@ -3077,8 +3077,6 @@ int call_netdevice_notifiers(unsigned long val, struct net_device *dev);
int call_netdevice_notifiers_info(unsigned long val,
struct netdev_notifier_info *info);
-extern rwlock_t dev_base_lock; /* Device list lock */
-
#define for_each_netdev(net, d) \
list_for_each_entry(d, &(net)->dev_base_head, dev_list)
#define for_each_netdev_reverse(net, d) \
@@ -166,28 +166,6 @@ static int call_netdevice_notifiers_extack(unsigned long val,
struct net_device *dev,
struct netlink_ext_ack *extack);
-/*
- * The @dev_base_head list is protected by @dev_base_lock and the rtnl
- * semaphore.
- *
- * Pure readers hold dev_base_lock for reading, or rcu_read_lock()
- *
- * Writers must hold the rtnl semaphore while they loop through the
- * dev_base_head list, and hold dev_base_lock for writing when they do the
- * actual updates. This allows pure readers to access the list even
- * while a writer is preparing to update it.
- *
- * To put it another way, dev_base_lock is held for writing only to
- * protect against pure readers; the rtnl semaphore provides the
- * protection against other writers.
- *
- * See, for example usages, register_netdevice() and
- * unregister_netdevice(), which must be called with the rtnl
- * semaphore held.
- */
-DEFINE_RWLOCK(dev_base_lock);
-EXPORT_SYMBOL(dev_base_lock);
-
static DEFINE_MUTEX(ifalias_mutex);
/* protects napi_hash addition/deletion and napi_gen_id */
@@ -393,12 +371,10 @@ static void list_netdevice(struct net_device *dev)
ASSERT_RTNL();
- write_lock(&dev_base_lock);
list_add_tail_rcu(&dev->dev_list, &net->dev_base_head);
netdev_name_node_add(net, dev->name_node);
hlist_add_head_rcu(&dev->index_hlist,
dev_index_hash(net, dev->ifindex));
- write_unlock(&dev_base_lock);
netdev_for_each_altname(dev, name_node)
netdev_name_node_add(net, name_node);
@@ -425,11 +401,9 @@ static void unlist_netdevice(struct net_device *dev)
netdev_name_node_del(name_node);
/* Unlink dev from the device chain */
- write_lock(&dev_base_lock);
list_del_rcu(&dev->dev_list);
netdev_name_node_del(dev->name_node);
hlist_del_rcu(&dev->index_hlist);
- write_unlock(&dev_base_lock);
dev_base_seq_inc(dev_net(dev));
}
@@ -744,9 +718,9 @@ EXPORT_SYMBOL_GPL(dev_fill_forward_path);
* @net: the applicable net namespace
* @name: name to find
*
- * Find an interface by name. Must be called under RTNL semaphore
- * or @dev_base_lock. If the name is found a pointer to the device
- * is returned. If the name is not found then %NULL is returned. The
+ * Find an interface by name. Must be called under RTNL semaphore.
+ * 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.
*/
@@ -827,8 +801,7 @@ EXPORT_SYMBOL(netdev_get_by_name);
* Search for an interface by index. Returns %NULL if the device
* is not found or a pointer to the device. The device has not
* had its reference counter increased so the caller must be careful
- * about locking. The caller must hold either the RTNL semaphore
- * or @dev_base_lock.
+ * about locking. The caller must hold the RTNL semaphore.
*/
struct net_device *__dev_get_by_index(struct net *net, int ifindex)
@@ -1233,15 +1206,11 @@ int dev_change_name(struct net_device *dev, const char *newname)
netdev_adjacent_rename_links(dev, oldname);
- write_lock(&dev_base_lock);
netdev_name_node_del(dev->name_node);
- write_unlock(&dev_base_lock);
synchronize_rcu();
- write_lock(&dev_base_lock);
netdev_name_node_add(net, dev->name_node);
- write_unlock(&dev_base_lock);
ret = call_netdevice_notifiers(NETDEV_CHANGENAME, dev);
ret = notifier_to_errno(ret);
dev_base_lock is not needed anymore, all remaining users also hold RTNL. Signed-off-by: Eric Dumazet <edumazet@google.com> --- include/linux/netdevice.h | 2 -- net/core/dev.c | 39 ++++----------------------------------- 2 files changed, 4 insertions(+), 37 deletions(-)