[XFRM]: Purge dst references to deleted SAs passively.

Just let GC and other normal mechanisms take care of getting
rid of DST cache references to deleted xfrm_state objects
instead of walking all the policy bundles.
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/xfrm.h

@@ -995,7 +995,6 @@ struct xfrm_state * xfrm_find_acq(u8 mode, u32 reqid, u8 proto,
 				  int create, unsigned short family);
 extern void xfrm_policy_flush(u8 type);
 extern int xfrm_sk_policy_insert(struct sock *sk, int dir, struct xfrm_policy *pol);
-extern int xfrm_flush_bundles(void);
 extern int xfrm_bundle_ok(struct xfrm_dst *xdst, struct flowi *fl, int family, int strict);
 extern void xfrm_init_pmtu(struct dst_entry *dst);
 

net/xfrm/xfrm_policy.c

@@ -1472,7 +1472,7 @@ static void __xfrm_garbage_collect(void)
 	xfrm_prune_bundles(unused_bundle);
 }
 
-int xfrm_flush_bundles(void)
+static int xfrm_flush_bundles(void)
 {
 	xfrm_prune_bundles(stale_bundle);
 	return 0;

net/xfrm/xfrm_state.c

@@ -256,8 +256,6 @@ static struct work_struct xfrm_state_gc_work;
 static HLIST_HEAD(xfrm_state_gc_list);
 static DEFINE_SPINLOCK(xfrm_state_gc_lock);
 
-static int xfrm_state_gc_flush_bundles;
-
 int __xfrm_state_delete(struct xfrm_state *x);
 
 static struct xfrm_state_afinfo *xfrm_state_get_afinfo(unsigned short family);
@@ -293,11 +291,6 @@ static void xfrm_state_gc_task(void *data)
 	struct hlist_node *entry, *tmp;
 	struct hlist_head gc_list;
 
-	if (xfrm_state_gc_flush_bundles) {
-		xfrm_state_gc_flush_bundles = 0;
-		xfrm_flush_bundles();
-	}
-
 	spin_lock_bh(&xfrm_state_gc_lock);
 	gc_list.first = xfrm_state_gc_list.first;
 	INIT_HLIST_HEAD(&xfrm_state_gc_list);
@@ -454,16 +447,6 @@ int __xfrm_state_delete(struct xfrm_state *x)
 		if (del_timer(&x->rtimer))
 			__xfrm_state_put(x);
 
-		/* The number two in this test is the reference
-		 * mentioned in the comment below plus the reference
-		 * our caller holds.  A larger value means that
-		 * there are DSTs attached to this xfrm_state.
-		 */
-		if (atomic_read(&x->refcnt) > 2) {
-			xfrm_state_gc_flush_bundles = 1;
-			schedule_work(&xfrm_state_gc_work);
-		}
-
 		/* All xfrm_state objects are created by xfrm_state_alloc.
 		 * The xfrm_state_alloc call gives a reference, and that
 		 * is what we are dropping here.