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 <[email protected]>
Acked-by: Steffen Klassert <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 4a9c21f9b4ea189075901a3f2c8c12ec6814f5fe..8bae1ef647cd43f366887e1faab44b72dbf9f4c4 100644 (file)
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -548,6 +548,7 @@ struct xfrm_policy {
        u16                     family;
        struct xfrm_sec_ctx     *security;
        struct xfrm_tmpl        xfrm_vec[XFRM_MAX_DEPTH];
+       struct rcu_head         rcu;
 };
 
 static inline struct net *xp_net(const struct xfrm_policy *xp)

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 18276f0cc32b56d5e71dc496bb7b991916922b96..f57a5712cedd1db8c4f53fca06fa4ae274e5892a 100644 (file)
--- 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);