[XFRM]: Simplify xfrm_policy_kill().

So here is a patch to simplify xfrm_policy_kill() by moving the
GC linking after the write_unlock_bh().

Actually, as the code stands, xfrm_policy_kill() should/will never
be called twice on the same policy.  So we can add a warning to
catch that.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 8 deletions

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index fbf8270619255c..80828078733dd9 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -13,6 +13,7 @@
  * 	
  */
 
+#include <asm/bug.h>
 #include <linux/config.h>
 #include <linux/slab.h>
 #include <linux/kmod.h>
@@ -300,20 +301,20 @@ static void xfrm_policy_gc_task(void *data)
 
 static void xfrm_policy_kill(struct xfrm_policy *policy)
 {
+	int dead;
+
 	write_lock_bh(&policy->lock);
-	if (policy->dead) {
-		write_unlock_bh(&policy->lock);
+	dead = policy->dead;
+	policy->dead = 1;
+	write_unlock_bh(&policy->lock);
+
+	if (unlikely(dead)) {
+		WARN_ON(1);
 		return;
 	}
-	policy->dead = 1;
 
 	spin_lock(&xfrm_policy_gc_lock);
 	list_add(&policy->list, &xfrm_policy_gc_list);
-	/*
-	 * Unlock the policy (out of order unlocking), to make sure
-	 * the GC context does not free it with an active lock:
-	 */
-	write_unlock_bh(&policy->lock);
 	spin_unlock(&xfrm_policy_gc_lock);
 
 	schedule_work(&xfrm_policy_gc_work);