xfrm: add rcu grace period in xfrm_policy_destroy()

We will soon switch sk->sk_policy[] to RCU protection,
as SYNACK packets are sent while listener socket is not locked.

This patch simply adds RCU grace period before struct xfrm_policy
freeing, and the corresponding rcu_head in struct xfrm_policy.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 2 deletions

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 18276f0cc32b..f57a5712cedd 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -303,6 +303,14 @@ struct xfrm_policy *xfrm_policy_alloc(struct net *net, gfp_t gfp)
 }
 EXPORT_SYMBOL(xfrm_policy_alloc);
 
+static void xfrm_policy_destroy_rcu(struct rcu_head *head)
+{
+        struct xfrm_policy *policy = container_of(head, struct xfrm_policy, rcu);
+
+        security_xfrm_policy_free(policy->security);
+        kfree(policy);
+}
+
 /* Destroy xfrm_policy: descendant resources must be released to this moment. */
 
 void xfrm_policy_destroy(struct xfrm_policy *policy)
@@ -312,8 +320,7 @@ void xfrm_policy_destroy(struct xfrm_policy *policy)
         if (del_timer(&policy->timer) || del_timer(&policy->polq.hold_timer))
                 BUG();
 
-        security_xfrm_policy_free(policy->security);
-        kfree(policy);
+        call_rcu(&policy->rcu, xfrm_policy_destroy_rcu);
 }
 EXPORT_SYMBOL(xfrm_policy_destroy);