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net: remove dev_base_lock

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dev_base_lock is not needed anymore, all remaining users also hold RTNL.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2024-02-13 06:32:45 +00:00 committed by David S. Miller
parent e51b962438
commit 1b3ef46cb7
2 changed files with 4 additions and 37 deletions
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2
include/linux/netdevice.h
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@ -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) \

39
net/core/dev.c
View File

@ -168,28 +168,6 @@ 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 */
@ -395,12 +373,10 @@ 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);
@ -427,11 +403,9 @@ 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));
}
@ -752,9 +726,9 @@ 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.
*/
@ -835,8 +809,7 @@ 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)
@ -1241,15 +1214,11 @@ rollback:
netdev_adjacent_rename_links(dev, oldname);
write_lock(&dev_base_lock);
netdev_name_node_del(dev->name_node);
write_unlock(&dev_base_lock);
synchronize_net();
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);