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net: remove default_device_exit()

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For some reason default_device_ops kept two exit method:

1) default_device_exit() is called for each netns being dismantled in
a cleanup_net() round. This acquires rtnl for each invocation.

2) default_device_exit_batch() is called once with the list of all netns
int the batch, allowing for a single rtnl invocation.

Get rid of the .exit() method to handle the logic from
default_device_exit_batch(), to decrease the number of rtnl acquisition
to one.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2022-02-07 20:50:38 -08:00 committed by Jakub Kicinski
parent 16a41634ac
commit ee403248fa
1 changed files with 14 additions and 8 deletions
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22
net/core/dev.c
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@ -10850,14 +10850,14 @@ static struct pernet_operations __net_initdata netdev_net_ops = {
.exit = netdev_exit,
};
static void __net_exit default_device_exit(struct net *net)
static void __net_exit default_device_exit_net(struct net *net)
{
struct net_device *dev, *aux;
/*
* Push all migratable network devices back to the
* initial network namespace
*/
rtnl_lock();
ASSERT_RTNL();
for_each_netdev_safe(net, dev, aux) {
int err;
char fb_name[IFNAMSIZ];
@ -10881,22 +10881,22 @@ static void __net_exit default_device_exit(struct net *net)
BUG();
}
}
rtnl_unlock();
}
static void __net_exit rtnl_lock_unregistering(struct list_head *net_list)
{
/* Return with the rtnl_lock held when there are no network
/* Return (with the rtnl_lock held) when there are no network
* devices unregistering in any network namespace in net_list.
*/
struct net *net;
bool unregistering;
DEFINE_WAIT_FUNC(wait, woken_wake_function);
bool unregistering;
struct net *net;
ASSERT_RTNL();
add_wait_queue(&netdev_unregistering_wq, &wait);
for (;;) {
unregistering = false;
rtnl_lock();
list_for_each_entry(net, net_list, exit_list) {
if (net->dev_unreg_count > 0) {
unregistering = true;
@ -10908,6 +10908,7 @@ static void __net_exit rtnl_lock_unregistering(struct list_head *net_list)
__rtnl_unlock();
wait_woken(&wait, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
rtnl_lock();
}
remove_wait_queue(&netdev_unregistering_wq, &wait);
}
@ -10923,6 +10924,11 @@ static void __net_exit default_device_exit_batch(struct list_head *net_list)
struct net *net;
LIST_HEAD(dev_kill_list);
rtnl_lock();
list_for_each_entry(net, net_list, exit_list) {
default_device_exit_net(net);
cond_resched();
}
/* To prevent network device cleanup code from dereferencing
* loopback devices or network devices that have been freed
* wait here for all pending unregistrations to complete,
@ -10935,6 +10941,7 @@ static void __net_exit default_device_exit_batch(struct list_head *net_list)
* default_device_exit_batch.
*/
rtnl_lock_unregistering(net_list);
list_for_each_entry(net, net_list, exit_list) {
for_each_netdev_reverse(net, dev) {
if (dev->rtnl_link_ops && dev->rtnl_link_ops->dellink)
@ -10948,7 +10955,6 @@ static void __net_exit default_device_exit_batch(struct list_head *net_list)
}
static struct pernet_operations __net_initdata default_device_ops = {
.exit = default_device_exit,
.exit_batch = default_device_exit_batch,
};