Commit 1b3ef46c authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net: remove dev_base_lock 



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

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e51b9624

include/linux/netdevice.h

+0 −2
Original line number Diff line number Diff line
@@ -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)	\

net/core/dev.c

+4 −35
Original line number Diff line number Diff line
@@ -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 @@ 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_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);