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net: Allow xfrm_user_net_exit to batch efficiently.

xfrm.nlsk is provided by the xfrm_user module and is access via rcu from
other parts of the xfrm code.  Add xfrm.nlsk_stash a copy of xfrm.nlsk that
will never be set to NULL.  This allows the synchronize_net and
netlink_kernel_release to be deferred until a whole batch of xfrm.nlsk sockets
have been set to NULL.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric W. Biederman 2009-12-03 02:29:05 +00:00 committed by David S. Miller
parent 04dc7f6be3
commit d79d792ef9
2 changed files with 11 additions and 8 deletions

View File

@ -43,6 +43,7 @@ struct netns_xfrm {
struct work_struct policy_hash_work;
struct sock *nlsk;
struct sock *nlsk_stash;
u32 sysctl_aevent_etime;
u32 sysctl_aevent_rseqth;

View File

@ -2721,22 +2721,24 @@ static int __net_init xfrm_user_net_init(struct net *net)
xfrm_netlink_rcv, NULL, THIS_MODULE);
if (nlsk == NULL)
return -ENOMEM;
net->xfrm.nlsk_stash = nlsk; /* Don't set to NULL */
rcu_assign_pointer(net->xfrm.nlsk, nlsk);
return 0;
}
static void __net_exit xfrm_user_net_exit(struct net *net)
static void __net_exit xfrm_user_net_exit(struct list_head *net_exit_list)
{
struct sock *nlsk = net->xfrm.nlsk;
rcu_assign_pointer(net->xfrm.nlsk, NULL);
synchronize_rcu();
netlink_kernel_release(nlsk);
struct net *net;
list_for_each_entry(net, net_exit_list, exit_list)
rcu_assign_pointer(net->xfrm.nlsk, NULL);
synchronize_net();
list_for_each_entry(net, net_exit_list, exit_list)
netlink_kernel_release(net->xfrm.nlsk_stash);
}
static struct pernet_operations xfrm_user_net_ops = {
.init = xfrm_user_net_init,
.exit = xfrm_user_net_exit,
.init = xfrm_user_net_init,
.exit_batch = xfrm_user_net_exit,
};
static int __init xfrm_user_init(void)