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>
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index fb42d77..1ada618 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -2721,22 +2721,24 @@
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)