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net: free altname using an RCU callback

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We had to add another synchronize_rcu() in recent fix.
Bite the bullet and add an rcu_head to netdev_name_node,
free from RCU.

Note that name_node does not hold any reference on dev
to which it points, but there must be a synchronize_rcu()
on device removal path, so we should be fine.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jakub Kicinski 2024-01-26 12:14:49 -08:00 committed by David S. Miller
parent 9e1aa985d6
commit 723de3ebef
2 changed files with 17 additions and 11 deletions
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27
net/core/dev.c
View File

@ -341,13 +341,22 @@ int netdev_name_node_alt_create(struct net_device *dev, const char *name)
return 0;
}
static void __netdev_name_node_alt_destroy(struct netdev_name_node *name_node)
static void netdev_name_node_alt_free(struct rcu_head *head)
{
list_del(&name_node->list);
struct netdev_name_node *name_node =
container_of(head, struct netdev_name_node, rcu);
kfree(name_node->name);
netdev_name_node_free(name_node);
}
static void __netdev_name_node_alt_destroy(struct netdev_name_node *name_node)
{
netdev_name_node_del(name_node);
list_del(&name_node->list);
call_rcu(&name_node->rcu, netdev_name_node_alt_free);
}
int netdev_name_node_alt_destroy(struct net_device *dev, const char *name)
{
struct netdev_name_node *name_node;
@ -362,10 +371,7 @@ int netdev_name_node_alt_destroy(struct net_device *dev, const char *name)
if (name_node == dev->name_node || name_node->dev != dev)
return -EINVAL;
netdev_name_node_del(name_node);
synchronize_rcu();
__netdev_name_node_alt_destroy(name_node);
return 0;
}
@ -373,8 +379,10 @@ static void netdev_name_node_alt_flush(struct net_device *dev)
{
struct netdev_name_node *name_node, *tmp;
list_for_each_entry_safe(name_node, tmp, &dev->name_node->list, list)
__netdev_name_node_alt_destroy(name_node);
list_for_each_entry_safe(name_node, tmp, &dev->name_node->list, list) {
list_del(&name_node->list);
netdev_name_node_alt_free(&name_node->rcu);
}
}
/* Device list insertion */
@ -11576,11 +11584,8 @@ static void __net_exit default_device_exit_net(struct net *net)
snprintf(fb_name, IFNAMSIZ, "dev%%d");
netdev_for_each_altname_safe(dev, name_node, tmp)
if (netdev_name_in_use(&init_net, name_node->name)) {
netdev_name_node_del(name_node);
synchronize_rcu();
if (netdev_name_in_use(&init_net, name_node->name))
__netdev_name_node_alt_destroy(name_node);
}
err = dev_change_net_namespace(dev, &init_net, fb_name);
if (err) {

1
net/core/dev.h
View File

@ -56,6 +56,7 @@ struct netdev_name_node {
struct list_head list;
struct net_device *dev;
const char *name;
struct rcu_head rcu;
};
int netdev_get_name(struct net *net, char *name, int ifindex);