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[3/4] xfrm: avoid synchronize_rcu during netns destruction

Message ID 20210423081409.729557-4-steffen.klassert@secunet.com (mailing list archive)
State Accepted
Commit 6218fe186109b93a2fa2343e13981e016e9961ab
Delegated to: Netdev Maintainers
Headers show
Series pull request (net-next): ipsec-next 2021-04-23 | expand

Checks

Context Check Description
netdev/tree_selection success Guessing tree name failed - patch did not apply

Commit Message

Steffen Klassert April 23, 2021, 8:14 a.m. UTC 
From: Florian Westphal <fw@strlen.de>

Use the new exit_pre hook to NULL the netlink socket.
The net namespace core will do a synchronize_rcu() between the exit_pre
and exit/exit_batch handlers.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
 net/xfrm/xfrm_user.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index df8bc8fc724c..f0aecee4d539 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -3480,18 +3480,22 @@  static int __net_init xfrm_user_net_init(struct net *net)
 	return 0;
 }
 
+static void __net_exit xfrm_user_net_pre_exit(struct net *net)
+{
+	RCU_INIT_POINTER(net->xfrm.nlsk, NULL);
+}
+
 static void __net_exit xfrm_user_net_exit(struct list_head *net_exit_list)
 {
 	struct net *net;
-	list_for_each_entry(net, net_exit_list, exit_list)
-		RCU_INIT_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,
+	.pre_exit   = xfrm_user_net_pre_exit,
 	.exit_batch = xfrm_user_net_exit,
 };