Commit d79d792e authored by Eric W. Biederman's avatar Eric W. Biederman Committed by David S. Miller
Browse files

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: default avatarEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 04dc7f6b

include/net/netns/xfrm.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

net/xfrm/xfrm_user.c

+10 −8
Original line number Diff line number Diff line
@@ -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;



	struct net *net;

	list_for_each_entry(net, net_exit_list, exit_list)

		rcu_assign_pointer(net->xfrm.nlsk, NULL);

	synchronize_rcu();

	netlink_kernel_release(nlsk);

	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,

	.exit_batch = xfrm_user_net_exit,

};



static int __init xfrm_user_init(void)

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