[NETFILTER]: nf_queue: remove unnecessary hook existance check

We hold a module reference for each queued packet, so the hook that
queued the packet can't disappear. Also remove an obsolete  comment
stating the opposite.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/netfilter/core.c

@@ -51,11 +51,6 @@ void nf_unregister_afinfo(struct nf_afinfo *afinfo)
 }
 EXPORT_SYMBOL_GPL(nf_unregister_afinfo);
 
-/* In this code, we can be waiting indefinitely for userspace to
- * service a packet if a hook returns NF_QUEUE.  We could keep a count
- * of skbuffs queued for userspace, and not deregister a hook unless
- * this is zero, but that sucks.  Now, we simply check when the
- * packets come back: if the hook is gone, the packet is discarded. */
 struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS] __read_mostly;
 EXPORT_SYMBOL(nf_hooks);
 static DEFINE_MUTEX(nf_hook_mutex);

net/netfilter/nf_queue.c

@@ -223,7 +223,6 @@ void nf_reinject(struct sk_buff *skb, struct nf_info *info,
 		 unsigned int verdict)
 {
 	struct list_head *elem = &info->elem->list;
-	struct list_head *i;
 	struct nf_afinfo *afinfo;
 
 	rcu_read_lock();
@@ -245,18 +244,6 @@ void nf_reinject(struct sk_buff *skb, struct nf_info *info,
 	/* Drop reference to owner of hook which queued us. */
 	module_put(info->elem->owner);
 
-	list_for_each_rcu(i, &nf_hooks[info->pf][info->hook]) {
-		if (i == elem)
-			break;
-	}
-
-	if (i == &nf_hooks[info->pf][info->hook]) {
-		/* The module which sent it to userspace is gone. */
-		NFDEBUG("%s: module disappeared, dropping packet.\n",
-			__FUNCTION__);
-		verdict = NF_DROP;
-	}
-
 	/* Continue traversal iff userspace said ok... */
 	if (verdict == NF_REPEAT) {
 		elem = elem->prev;