[PATCH nf-next v3 0/7] Compact netfilter hooks list

@@ -1783,7 +1783,7 @@ struct net_device {
 #endif
 	struct netdev_queue __rcu *ingress_queue;
 #ifdef CONFIG_NETFILTER_INGRESS
-	struct list_head	nf_hooks_ingress;
+	struct nf_hook_entry __rcu *nf_hooks_ingress;
 #endif
 
 	unsigned char		broadcast[MAX_ADDR_LEN];

@@ -55,12 +55,34 @@ struct nf_hook_state {
 	struct net_device *out;
 	struct sock *sk;
 	struct net *net;
-	struct list_head *hook_list;
+	struct nf_hook_entry __rcu *hook_entries;
 	int (*okfn)(struct net *, struct sock *, struct sk_buff *);
 };
 
+typedef unsigned int nf_hookfn(void *priv,
+			       struct sk_buff *skb,
+			       const struct nf_hook_state *state);
+struct nf_hook_ops {
+	struct list_head	list;
+
+	/* User fills in from here down. */
+	nf_hookfn		*hook;
+	struct net_device	*dev;
+	void			*priv;
+	u_int8_t		pf;
+	unsigned int		hooknum;
+	/* Hooks are ordered in ascending priority. */
+	int			priority;
+};
+
+struct nf_hook_entry {
+	struct nf_hook_entry __rcu	*next;
+	struct nf_hook_ops		ops;
+	const struct nf_hook_ops	*orig_ops;
+};
+
 static inline void nf_hook_state_init(struct nf_hook_state *p,
-				      struct list_head *hook_list,
+				      struct nf_hook_entry *hook_entry,
 				      unsigned int hook,
 				      int thresh, u_int8_t pf,
 				      struct net_device *indev,

@@ -76,26 +98,11 @@ static inline void nf_hook_state_init(struct nf_hook_state *p,
 	p->out = outdev;
 	p->sk = sk;
 	p->net = net;
-	p->hook_list = hook_list;
+	RCU_INIT_POINTER(p->hook_entries, hook_entry);
 	p->okfn = okfn;
 }
 
-typedef unsigned int nf_hookfn(void *priv,
-			       struct sk_buff *skb,
-			       const struct nf_hook_state *state);
 
-struct nf_hook_ops {
-	struct list_head 	list;
-
-	/* User fills in from here down. */
-	nf_hookfn		*hook;
-	struct net_device	*dev;
-	void			*priv;
-	u_int8_t		pf;
-	unsigned int		hooknum;
-	/* Hooks are ordered in ascending priority. */
-	int			priority;
-};
 
 struct nf_sockopt_ops {
 	struct list_head list;

@@ -161,7 +168,8 @@ static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
 				 int (*okfn)(struct net *, struct sock *, struct sk_buff *),
 				 int thresh)
 {
-	struct list_head *hook_list;
+	struct nf_hook_entry *hook_head;
+	int ret = 1;
 
 #ifdef HAVE_JUMP_LABEL
 	if (__builtin_constant_p(pf) &&

@@ -170,22 +178,19 @@ static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
 		return 1;
 #endif
 
-	hook_list = &net->nf.hooks[pf][hook];
+	rcu_read_lock();
 
-	if (!list_empty(hook_list)) {
+	hook_head = rcu_dereference(net->nf.hooks[pf][hook]);
+	if (hook_head) {
 		struct nf_hook_state state;
-		int ret;
 
-		/* We may already have this, but read-locks nest anyway */
-		rcu_read_lock();
-		nf_hook_state_init(&state, hook_list, hook, thresh,
+		nf_hook_state_init(&state, hook_head, hook, thresh,
 				   pf, indev, outdev, sk, net, okfn);
 
 		ret = nf_hook_slow(skb, &state);
-		rcu_read_unlock();
-		return ret;
 	}
-	return 1;
+	rcu_read_unlock();
+	return ret;
 }
 
 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,

@@ -11,23 +11,29 @@ static inline bool nf_hook_ingress_active(const struct sk_buff *skb)
 	if (!static_key_false(&nf_hooks_needed[NFPROTO_NETDEV][NF_NETDEV_INGRESS]))
 		return false;
 #endif
-	return !list_empty(&skb->dev->nf_hooks_ingress);
+	return rcu_access_pointer(skb->dev->nf_hooks_ingress);
 }
 
 /* caller must hold rcu_read_lock */
 static inline int nf_hook_ingress(struct sk_buff *skb)
 {
+	struct nf_hook_entry *e = rcu_dereference(skb->dev->nf_hooks_ingress);
 	struct nf_hook_state state;
 
-	nf_hook_state_init(&state, &skb->dev->nf_hooks_ingress,
-			   NF_NETDEV_INGRESS, INT_MIN, NFPROTO_NETDEV,
-			   skb->dev, NULL, NULL, dev_net(skb->dev), NULL);
+	/* must recheck the ingress hook head, in the event it became NULL
+	 * after the check in nf_hook_ingress_active evaluated to true. */
+	if (unlikely(!e))
+		return 0;
+
+	nf_hook_state_init(&state, e, NF_NETDEV_INGRESS, INT_MIN,
+			   NFPROTO_NETDEV, skb->dev, NULL, NULL,
+			   dev_net(skb->dev), NULL);
 	return nf_hook_slow(skb, &state);
 }
 
 static inline void nf_hook_ingress_init(struct net_device *dev)
 {
-	INIT_LIST_HEAD(&dev->nf_hooks_ingress);
+	RCU_INIT_POINTER(dev->nf_hooks_ingress, NULL);
 }
 #else /* CONFIG_NETFILTER_INGRESS */
 static inline int nf_hook_ingress_active(struct sk_buff *skb)

@@ -11,7 +11,6 @@ struct nf_queue_entry {
 	struct sk_buff		*skb;
 	unsigned int		id;
 
-	struct nf_hook_ops	*elem;
 	struct nf_hook_state	state;
 	u16			size; /* sizeof(entry) + saved route keys */
 

@@ -25,7 +24,7 @@ struct nf_queue_handler {
 	int		(*outfn)(struct nf_queue_entry *entry,
 				 unsigned int queuenum);
 	void		(*nf_hook_drop)(struct net *net,
-					struct nf_hook_ops *ops);
+					const struct nf_hook_entry *hooks);
 };
 
 void nf_register_queue_handler(struct net *net, const struct nf_queue_handler *qh);

@@ -16,6 +16,6 @@ struct netns_nf {
 #ifdef CONFIG_SYSCTL
 	struct ctl_table_header *nf_log_dir_header;
 #endif
-	struct list_head hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
+	struct nf_hook_entry __rcu *hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
 };
 #endif

@@ -1002,28 +1002,21 @@ int br_nf_hook_thresh(unsigned int hook, struct net *net,
 		      int (*okfn)(struct net *, struct sock *,
 				  struct sk_buff *))
 {
-	struct nf_hook_ops *elem;
+	struct nf_hook_entry *elem;
 	struct nf_hook_state state;
-	struct list_head *head;
 	int ret;
 
-	head = &net->nf.hooks[NFPROTO_BRIDGE][hook];
+	elem = rcu_dereference(net->nf.hooks[NFPROTO_BRIDGE][hook]);
 
-	list_for_each_entry_rcu(elem, head, list) {
-		struct nf_hook_ops *next;
+	while (elem && (elem->ops.priority <= NF_BR_PRI_BRNF))
+		elem = rcu_dereference(elem->next);
 
-		next = list_entry_rcu(list_next_rcu(&elem->list),
-				      struct nf_hook_ops, list);
-		if (next->priority <= NF_BR_PRI_BRNF)
-			continue;
-	}
-
-	if (&elem->list == head)
+	if (!elem)
 		return okfn(net, sk, skb);
 
 	/* We may already have this, but read-locks nest anyway */
 	rcu_read_lock();
-	nf_hook_state_init(&state, head, hook, NF_BR_PRI_BRNF + 1,
+	nf_hook_state_init(&state, elem, hook, NF_BR_PRI_BRNF + 1,
 			   NFPROTO_BRIDGE, indev, outdev, sk, net, okfn);
 
 	ret = nf_hook_slow(skb, &state);

@@ -22,6 +22,7 @@
 #include <linux/proc_fs.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
+#include <linux/rcupdate.h>
 #include <net/net_namespace.h>
 #include <net/sock.h>
 

@@ -61,33 +62,50 @@ EXPORT_SYMBOL(nf_hooks_needed);
 #endif
 
 static DEFINE_MUTEX(nf_hook_mutex);
+#define nf_entry_dereference(e) \
+	rcu_dereference_protected(e, lockdep_is_held(&nf_hook_mutex))
 
-static struct list_head *nf_find_hook_list(struct net *net,
-					   const struct nf_hook_ops *reg)
+static struct nf_hook_entry *nf_hook_entry_head(struct net *net,
+						const struct nf_hook_ops *reg)
 {
-	struct list_head *hook_list = NULL;
+	struct nf_hook_entry *hook_head = NULL;
 
 	if (reg->pf != NFPROTO_NETDEV)
-		hook_list = &net->nf.hooks[reg->pf][reg->hooknum];
+		hook_head = nf_entry_dereference(net->nf.hooks[reg->pf]
+						 [reg->hooknum]);
 	else if (reg->hooknum == NF_NETDEV_INGRESS) {
 #ifdef CONFIG_NETFILTER_INGRESS
 		if (reg->dev && dev_net(reg->dev) == net)
-			hook_list = &reg->dev->nf_hooks_ingress;
+			hook_head =
+				nf_entry_dereference(
+					reg->dev->nf_hooks_ingress);
 #endif
 	}
-	return hook_list;
+	return hook_head;
 }
 
-struct nf_hook_entry {
-	const struct nf_hook_ops	*orig_ops;
-	struct nf_hook_ops		ops;
-};
+/* must hold nf_hook_mutex */
+static void nf_set_hooks_head(struct net *net, const struct nf_hook_ops *reg,
+			      struct nf_hook_entry *entry)
+{
+	switch (reg->pf) {
+	case NFPROTO_NETDEV:
+		/* We already checked in nf_register_net_hook() that this is
+		 * used from ingress.
+		 */
+		rcu_assign_pointer(reg->dev->nf_hooks_ingress, entry);
+		break;
+	default:
+		rcu_assign_pointer(net->nf.hooks[reg->pf][reg->hooknum],
+				   entry);
+		break;
+	}
+}
 
 int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg)
 {
-	struct list_head *hook_list;
+	struct nf_hook_entry *hooks_entry;
 	struct nf_hook_entry *entry;
-	struct nf_hook_ops *elem;
 
 	if (reg->pf == NFPROTO_NETDEV &&
 	    (reg->hooknum != NF_NETDEV_INGRESS ||

@@ -100,19 +118,30 @@ int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg)
 
 	entry->orig_ops	= reg;
 	entry->ops	= *reg;
+	entry->next	= NULL;
+
+	mutex_lock(&nf_hook_mutex);
+	hooks_entry = nf_hook_entry_head(net, reg);
 
-	hook_list = nf_find_hook_list(net, reg);
-	if (!hook_list) {
-		kfree(entry);
-		return -ENOENT;
+	if (hooks_entry && hooks_entry->orig_ops->priority > reg->priority) {
+		/* This is the case where we need to insert at the head */
+		entry->next = hooks_entry;
+		hooks_entry = NULL;
 	}
 
-	mutex_lock(&nf_hook_mutex);
-	list_for_each_entry(elem, hook_list, list) {
-		if (reg->priority < elem->priority)
-			break;
+	while (hooks_entry &&
+	       reg->priority >= hooks_entry->orig_ops->priority &&
+	       nf_entry_dereference(hooks_entry->next)) {
+		hooks_entry = nf_entry_dereference(hooks_entry->next);
+	}
+
+	if (hooks_entry) {
+		entry->next = nf_entry_dereference(hooks_entry->next);
+		rcu_assign_pointer(hooks_entry->next, entry);
+	} else {
+		nf_set_hooks_head(net, reg, entry);
 	}
-	list_add_rcu(&entry->ops.list, elem->list.prev);
+
 	mutex_unlock(&nf_hook_mutex);
 #ifdef CONFIG_NETFILTER_INGRESS
 	if (reg->pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS)

@@ -127,24 +156,33 @@ EXPORT_SYMBOL(nf_register_net_hook);
 
 void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *reg)
 {
-	struct list_head *hook_list;
-	struct nf_hook_entry *entry;
-	struct nf_hook_ops *elem;
-
-	hook_list = nf_find_hook_list(net, reg);
-	if (!hook_list)
-		return;
+	struct nf_hook_entry *hooks_entry;
 
 	mutex_lock(&nf_hook_mutex);
-	list_for_each_entry(elem, hook_list, list) {
-		entry = container_of(elem, struct nf_hook_entry, ops);
-		if (entry->orig_ops == reg) {
-			list_del_rcu(&entry->ops.list);
-			break;
+	hooks_entry = nf_hook_entry_head(net, reg);
+	if (hooks_entry->orig_ops == reg) {
+		nf_set_hooks_head(net, reg,
+				  nf_entry_dereference(hooks_entry->next));
+		goto unlock;
+	}
+	while (hooks_entry && nf_entry_dereference(hooks_entry->next)) {
+		struct nf_hook_entry *next =
+			nf_entry_dereference(hooks_entry->next);
+		struct nf_hook_entry *nnext;
+
+		if (next->orig_ops != reg) {
+			hooks_entry = next;
+			continue;
 		}
+		nnext = nf_entry_dereference(next->next);
+		rcu_assign_pointer(hooks_entry->next, nnext);
+		hooks_entry = next;
+		break;
 	}
+
+unlock:
 	mutex_unlock(&nf_hook_mutex);
-	if (&elem->list == hook_list) {
+	if (!hooks_entry) {
 		WARN(1, "nf_unregister_net_hook: hook not found!\n");
 		return;
 	}

@@ -156,10 +194,10 @@ void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *reg)
 	static_key_slow_dec(&nf_hooks_needed[reg->pf][reg->hooknum]);
 #endif
 	synchronize_net();
-	nf_queue_nf_hook_drop(net, &entry->ops);
+	nf_queue_nf_hook_drop(net, hooks_entry);
 	/* other cpu might still process nfqueue verdict that used reg */
 	synchronize_net();
-	kfree(entry);
+	kfree(hooks_entry);
 }
 EXPORT_SYMBOL(nf_unregister_net_hook);
 

@@ -258,10 +296,9 @@ void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n)
 }
 EXPORT_SYMBOL(nf_unregister_hooks);
 
-unsigned int nf_iterate(struct list_head *head,
-			struct sk_buff *skb,
+unsigned int nf_iterate(struct sk_buff *skb,
 			struct nf_hook_state *state,
-			struct nf_hook_ops **elemp)
+			struct nf_hook_entry **entryp)
 {
 	unsigned int verdict;
 

@@ -269,20 +306,23 @@ unsigned int nf_iterate(struct list_head *head,
 	 * The caller must not block between calls to this
 	 * function because of risk of continuing from deleted element.
 	 */
-	list_for_each_entry_continue_rcu((*elemp), head, list) {
-		if (state->thresh > (*elemp)->priority)
+	while (*entryp) {
+		if (state->thresh > (*entryp)->ops.priority) {
+			*entryp = rcu_dereference((*entryp)->next);
 			continue;
+		}
 
 		/* Optimization: we don't need to hold module
 		   reference here, since function can't sleep. --RR */
 repeat:
-		verdict = (*elemp)->hook((*elemp)->priv, skb, state);
+		verdict = (*entryp)->ops.hook((*entryp)->ops.priv, skb, state);
 		if (verdict != NF_ACCEPT) {
 #ifdef CONFIG_NETFILTER_DEBUG
 			if (unlikely((verdict & NF_VERDICT_MASK)
 							> NF_MAX_VERDICT)) {
 				NFDEBUG("Evil return from %p(%u).\n",
-					(*elemp)->hook, state->hook);
+					(*entryp)->ops.hook, state->hook);
+				*entryp = rcu_dereference((*entryp)->next);
 				continue;
 			}
 #endif

@@ -290,6 +330,7 @@ repeat:
 				return verdict;
 			goto repeat;
 		}
+		*entryp = rcu_dereference((*entryp)->next);
 	}
 	return NF_ACCEPT;
 }

@@ -299,13 +340,13 @@ repeat:
  * -EPERM for NF_DROP, 0 otherwise.  Caller must hold rcu_read_lock. */
 int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state)
 {
-	struct nf_hook_ops *elem;
+	struct nf_hook_entry *entry;
 	unsigned int verdict;
 	int ret = 0;
 
-	elem = list_entry_rcu(state->hook_list, struct nf_hook_ops, list);
+	entry = rcu_dereference(state->hook_entries);
 next_hook:
-	verdict = nf_iterate(state->hook_list, skb, state, &elem);
+	verdict = nf_iterate(skb, state, &entry);
 	if (verdict == NF_ACCEPT || verdict == NF_STOP) {
 		ret = 1;
 	} else if ((verdict & NF_VERDICT_MASK) == NF_DROP) {

@@ -314,8 +355,10 @@ next_hook:
 		if (ret == 0)
 			ret = -EPERM;
 	} else if ((verdict & NF_VERDICT_MASK) == NF_QUEUE) {
-		int err = nf_queue(skb, elem, state,
-				   verdict >> NF_VERDICT_QBITS);
+		int err;
+
+		RCU_INIT_POINTER(state->hook_entries, entry);
+		err = nf_queue(skb, state, verdict >> NF_VERDICT_QBITS);
 		if (err < 0) {
 			if (err == -ESRCH &&
 			   (verdict & NF_VERDICT_FLAG_QUEUE_BYPASS))

@@ -442,7 +485,7 @@ static int __net_init netfilter_net_init(struct net *net)
 
 	for (i = 0; i < ARRAY_SIZE(net->nf.hooks); i++) {
 		for (h = 0; h < NF_MAX_HOOKS; h++)
-			INIT_LIST_HEAD(&net->nf.hooks[i][h]);
+			RCU_INIT_POINTER(net->nf.hooks[i][h], NULL);
 	}
 
 #ifdef CONFIG_PROC_FS

@@ -13,13 +13,13 @@
 
 
 /* core.c */
-unsigned int nf_iterate(struct list_head *head, struct sk_buff *skb,
-			struct nf_hook_state *state, struct nf_hook_ops **elemp);
+unsigned int nf_iterate(struct sk_buff *skb, struct nf_hook_state *state,
+			struct nf_hook_entry **entryp);
 
 /* nf_queue.c */
-int nf_queue(struct sk_buff *skb, struct nf_hook_ops *elem,
-	     struct nf_hook_state *state, unsigned int queuenum);
-void nf_queue_nf_hook_drop(struct net *net, struct nf_hook_ops *ops);
+int nf_queue(struct sk_buff *skb, struct nf_hook_state *state,
+	     unsigned int queuenum);
+void nf_queue_nf_hook_drop(struct net *net, const struct nf_hook_entry *entry);
 int __init netfilter_queue_init(void);
 
 /* nf_log.c */

@@ -96,14 +96,14 @@ void nf_queue_entry_get_refs(struct nf_queue_entry *entry)
 }
 EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
 
-void nf_queue_nf_hook_drop(struct net *net, struct nf_hook_ops *ops)
+void nf_queue_nf_hook_drop(struct net *net, const struct nf_hook_entry *entry)
 {
 	const struct nf_queue_handler *qh;
 
 	rcu_read_lock();
 	qh = rcu_dereference(net->nf.queue_handler);
 	if (qh)
-		qh->nf_hook_drop(net, ops);
+		qh->nf_hook_drop(net, entry);
 	rcu_read_unlock();
 }
 

@@ -112,7 +112,6 @@ void nf_queue_nf_hook_drop(struct net *net, struct nf_hook_ops *ops)
  * through nf_reinject().
  */
 int nf_queue(struct sk_buff *skb,
-	     struct nf_hook_ops *elem,
 	     struct nf_hook_state *state,
 	     unsigned int queuenum)
 {

@@ -141,7 +140,6 @@ int nf_queue(struct sk_buff *skb,
 
 	*entry = (struct nf_queue_entry) {
 		.skb	= skb,
-		.elem	= elem,
 		.state	= *state,
 		.size	= sizeof(*entry) + afinfo->route_key_size,
 	};

@@ -165,11 +163,15 @@ err:
 
 void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
 {
+	struct nf_hook_entry *hook_entry;
 	struct sk_buff *skb = entry->skb;
-	struct nf_hook_ops *elem = entry->elem;
 	const struct nf_afinfo *afinfo;
+	struct nf_hook_ops *elem;
 	int err;
 
+	hook_entry = rcu_dereference(entry->state.hook_entries);
+	elem = &hook_entry->ops;
+
 	nf_queue_entry_release_refs(entry);
 
 	/* Continue traversal iff userspace said ok... */

@@ -186,8 +188,7 @@ void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
 
 	if (verdict == NF_ACCEPT) {
 	next_hook:
-		verdict = nf_iterate(entry->state.hook_list,
-				     skb, &entry->state, &elem);
+		verdict = nf_iterate(skb, &entry->state, &hook_entry);
 	}
 
 	switch (verdict & NF_VERDICT_MASK) {

@@ -198,7 +199,8 @@ void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict)
 		local_bh_enable();
 		break;
 	case NF_QUEUE:
-		err = nf_queue(skb, elem, &entry->state,
+		RCU_INIT_POINTER(entry->state.hook_entries, hook_entry);
+		err = nf_queue(skb, &entry->state,
 			       verdict >> NF_VERDICT_QBITS);
 		if (err < 0) {
 			if (err == -ESRCH &&

@@ -917,12 +917,14 @@ static struct notifier_block nfqnl_dev_notifier = {
 	.notifier_call	= nfqnl_rcv_dev_event,
 };
 
-static int nf_hook_cmp(struct nf_queue_entry *entry, unsigned long ops_ptr)
+static int nf_hook_cmp(struct nf_queue_entry *entry, unsigned long entry_ptr)
 {
-	return entry->elem == (struct nf_hook_ops *)ops_ptr;
+	return rcu_access_pointer(entry->state.hook_entries) ==
+		(struct nf_hook_entry *)entry_ptr;
 }
 
-static void nfqnl_nf_hook_drop(struct net *net, struct nf_hook_ops *hook)
+static void nfqnl_nf_hook_drop(struct net *net,
+			       const struct nf_hook_entry *hook)
 {
 	struct nfnl_queue_net *q = nfnl_queue_pernet(net);
 	int i;

@@ -15,6 +15,12 @@ static inline struct nf_bridge_info *nf_bridge_alloc(struct sk_buff *skb)
 
 void nf_bridge_update_protocol(struct sk_buff *skb);
 
+int br_nf_hook_thresh(unsigned int hook, struct net *net, struct sock *sk,
+		      struct sk_buff *skb, struct net_device *indev,
+		      struct net_device *outdev,
+		      int (*okfn)(struct net *, struct sock *,
+				  struct sk_buff *));
+
 static inline struct nf_bridge_info *
 nf_bridge_info_get(const struct sk_buff *skb)
 {

@@ -30,6 +30,7 @@
 #include <linux/netfilter_ipv6.h>
 #include <linux/netfilter_arp.h>
 #include <linux/in_route.h>
+#include <linux/rculist.h>
 #include <linux/inetdevice.h>
 
 #include <net/ip.h>

@@ -395,11 +396,10 @@ bridged_dnat:
 				skb->dev = nf_bridge->physindev;
 				nf_bridge_update_protocol(skb);
 				nf_bridge_push_encap_header(skb);
-				NF_HOOK_THRESH(NFPROTO_BRIDGE,
-					       NF_BR_PRE_ROUTING,
-					       net, sk, skb, skb->dev, NULL,
-					       br_nf_pre_routing_finish_bridge,
-					       1);
+				br_nf_hook_thresh(NF_BR_PRE_ROUTING,
+						  net, sk, skb, skb->dev,
+						  NULL,
+						  br_nf_pre_routing_finish);
 				return 0;
 			}
 			ether_addr_copy(eth_hdr(skb)->h_dest, dev->dev_addr);

@@ -417,10 +417,8 @@ bridged_dnat:
 	skb->dev = nf_bridge->physindev;
 	nf_bridge_update_protocol(skb);
 	nf_bridge_push_encap_header(skb);
-	NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, net, sk, skb,
-		       skb->dev, NULL,
-		       br_handle_frame_finish, 1);
-
+	br_nf_hook_thresh(NF_BR_PRE_ROUTING, net, sk, skb, skb->dev, NULL,
+			  br_handle_frame_finish);
 	return 0;
 }
 

@@ -992,6 +990,50 @@ static struct notifier_block brnf_notifier __read_mostly = {
 	.notifier_call = brnf_device_event,
 };
 
+/* recursively invokes nf_hook_slow (again), skipping already-called
+ * hooks (< NF_BR_PRI_BRNF).
+ *
+ * Called with rcu read lock held.
+ */
+int br_nf_hook_thresh(unsigned int hook, struct net *net,
+		      struct sock *sk, struct sk_buff *skb,
+		      struct net_device *indev,
+		      struct net_device *outdev,
+		      int (*okfn)(struct net *, struct sock *,
+				  struct sk_buff *))
+{
+	struct nf_hook_ops *elem;
+	struct nf_hook_state state;
+	struct list_head *head;
+	int ret;
+
+	head = &net->nf.hooks[NFPROTO_BRIDGE][hook];
+
+	list_for_each_entry_rcu(elem, head, list) {
+		struct nf_hook_ops *next;
+
+		next = list_entry_rcu(list_next_rcu(&elem->list),
+				      struct nf_hook_ops, list);
+		if (next->priority <= NF_BR_PRI_BRNF)
+			continue;
+	}
+
+	if (&elem->list == head)
+		return okfn(net, sk, skb);
+
+	/* We may already have this, but read-locks nest anyway */
+	rcu_read_lock();
+	nf_hook_state_init(&state, head, hook, NF_BR_PRI_BRNF + 1,
+			   NFPROTO_BRIDGE, indev, outdev, sk, net, okfn);
+
+	ret = nf_hook_slow(skb, &state);
+	rcu_read_unlock();
+	if (ret == 1)
+		ret = okfn(net, sk, skb);
+
+	return ret;
+}
+
 #ifdef CONFIG_SYSCTL
 static
 int brnf_sysctl_call_tables(struct ctl_table *ctl, int write,

@@ -187,10 +187,9 @@ static int br_nf_pre_routing_finish_ipv6(struct net *net, struct sock *sk, struc
 			skb->dev = nf_bridge->physindev;
 			nf_bridge_update_protocol(skb);
 			nf_bridge_push_encap_header(skb);
-			NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING,
-				       net, sk, skb, skb->dev, NULL,
-				       br_nf_pre_routing_finish_bridge,
-				       1);
+			br_nf_hook_thresh(NF_BR_PRE_ROUTING,
+					  net, sk, skb, skb->dev, NULL,
+					  br_nf_pre_routing_finish_bridge);
 			return 0;
 		}
 		ether_addr_copy(eth_hdr(skb)->h_dest, dev->dev_addr);

@@ -207,9 +206,8 @@ static int br_nf_pre_routing_finish_ipv6(struct net *net, struct sock *sk, struc
 	skb->dev = nf_bridge->physindev;
 	nf_bridge_update_protocol(skb);
 	nf_bridge_push_encap_header(skb);
-	NF_HOOK_THRESH(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, net, sk, skb,
-		       skb->dev, NULL,
-		       br_handle_frame_finish, 1);
+	br_nf_hook_thresh(NF_BR_PRE_ROUTING, net, sk, skb,
+			  skb->dev, NULL, br_handle_frame_finish);
 
 	return 0;
 }

@@ -174,10 +174,16 @@ static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
 
 	if (!list_empty(hook_list)) {
 		struct nf_hook_state state;
+		int ret;
 
+		/* We may already have this, but read-locks nest anyway */
+		rcu_read_lock();
 		nf_hook_state_init(&state, hook_list, hook, thresh,
 				   pf, indev, outdev, sk, net, okfn);
-		return nf_hook_slow(skb, &state);
+
+		ret = nf_hook_slow(skb, &state);
+		rcu_read_unlock();
+		return ret;
 	}
 	return 1;
 }

@@ -14,6 +14,7 @@ static inline bool nf_hook_ingress_active(const struct sk_buff *skb)
 	return !list_empty(&skb->dev->nf_hooks_ingress);
 }
 
+/* caller must hold rcu_read_lock */
 static inline int nf_hook_ingress(struct sk_buff *skb)
 {
 	struct nf_hook_state state;

@@ -4040,12 +4040,17 @@ static inline int nf_ingress(struct sk_buff *skb, struct packet_type **pt_prev,
 {
 #ifdef CONFIG_NETFILTER_INGRESS
 	if (nf_hook_ingress_active(skb)) {
+		int ingress_retval;
+
 		if (*pt_prev) {
 			*ret = deliver_skb(skb, *pt_prev, orig_dev);
 			*pt_prev = NULL;
 		}
 
-		return nf_hook_ingress(skb);
+		rcu_read_lock();
+		ingress_retval = nf_hook_ingress(skb);
+		rcu_read_unlock();
+		return ingress_retval;
 	}
 #endif /* CONFIG_NETFILTER_INGRESS */
 	return 0;

@@ -24,7 +24,7 @@ ebt_redirect_tg(struct sk_buff *skb, const struct xt_action_param *par)
 		return EBT_DROP;
 
 	if (par->hooknum != NF_BR_BROUTING)
-		/* rcu_read_lock()ed by nf_hook_slow */
+		/* rcu_read_lock()ed by nf_hook_thresh */
 		ether_addr_copy(eth_hdr(skb)->h_dest,
 				br_port_get_rcu(par->in)->br->dev->dev_addr);
 	else

@@ -146,7 +146,7 @@ ebt_basic_match(const struct ebt_entry *e, const struct sk_buff *skb,
 		return 1;
 	if (NF_INVF(e, EBT_IOUT, ebt_dev_check(e->out, out)))
 		return 1;
-	/* rcu_read_lock()ed by nf_hook_slow */
+	/* rcu_read_lock()ed by nf_hook_thresh */
 	if (in && (p = br_port_get_rcu(in)) != NULL &&
 	    NF_INVF(e, EBT_ILOGICALIN,
 		    ebt_dev_check(e->logical_in, p->br->dev)))

@@ -110,7 +110,7 @@ static unsigned int ipv4_helper(void *priv,
 	if (!help)
 		return NF_ACCEPT;
 
-	/* rcu_read_lock()ed by nf_hook_slow */
+	/* rcu_read_lock()ed by nf_hook_thresh */
 	helper = rcu_dereference(help->helper);
 	if (!helper)
 		return NF_ACCEPT;

@@ -149,7 +149,7 @@ icmp_error_message(struct net *net, struct nf_conn *tmpl, struct sk_buff *skb,
 		return -NF_ACCEPT;
 	}
 
-	/* rcu_read_lock()ed by nf_hook_slow */
+	/* rcu_read_lock()ed by nf_hook_thresh */
 	innerproto = __nf_ct_l4proto_find(PF_INET, origtuple.dst.protonum);
 
 	/* Ordinarily, we'd expect the inverted tupleproto, but it's

@@ -115,7 +115,7 @@ static unsigned int ipv6_helper(void *priv,
 	help = nfct_help(ct);
 	if (!help)
 		return NF_ACCEPT;
-	/* rcu_read_lock()ed by nf_hook_slow */
+	/* rcu_read_lock()ed by nf_hook_thresh */
 	helper = rcu_dereference(help->helper);
 	if (!helper)
 		return NF_ACCEPT;

@@ -165,7 +165,7 @@ icmpv6_error_message(struct net *net, struct nf_conn *tmpl,
 		return -NF_ACCEPT;
 	}
 
-	/* rcu_read_lock()ed by nf_hook_slow */
+	/* rcu_read_lock()ed by nf_hook_thresh */
 	inproto = __nf_ct_l4proto_find(PF_INET6, origtuple.dst.protonum);
 
 	/* Ordinarily, we'd expect the inverted tupleproto, but it's

@@ -291,16 +291,13 @@ repeat:
 
 
 /* Returns 1 if okfn() needs to be executed by the caller,
- * -EPERM for NF_DROP, 0 otherwise. */
+ * -EPERM for NF_DROP, 0 otherwise.  Caller must hold rcu_read_lock. */
 int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state)
 {
 	struct nf_hook_ops *elem;
 	unsigned int verdict;
 	int ret = 0;
 
-	/* We may already have this, but read-locks nest anyway */
-	rcu_read_lock();
-
 	elem = list_entry_rcu(state->hook_list, struct nf_hook_ops, list);
 next_hook:
 	verdict = nf_iterate(state->hook_list, skb, state, &elem);

@@ -321,7 +318,6 @@ next_hook:
 			kfree_skb(skb);
 		}
 	}
-	rcu_read_unlock();
 	return ret;
 }
 EXPORT_SYMBOL(nf_hook_slow);

@@ -1275,7 +1275,7 @@ nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
 		skb->nfct = NULL;
 	}
 
-	/* rcu_read_lock()ed by nf_hook_slow */
+	/* rcu_read_lock()ed by nf_hook_thresh */
 	l3proto = __nf_ct_l3proto_find(pf);
 	ret = l3proto->get_l4proto(skb, skb_network_offset(skb),
 				   &dataoff, &protonum);

@@ -736,7 +736,7 @@ static int callforward_do_filter(struct net *net,
 	const struct nf_afinfo *afinfo;
 	int ret = 0;
 
-	/* rcu_read_lock()ed by nf_hook_slow() */
+	/* rcu_read_lock()ed by nf_hook_thresh */
 	afinfo = nf_get_afinfo(family);
 	if (!afinfo)
 		return 0;

@@ -346,7 +346,7 @@ void nf_ct_helper_log(struct sk_buff *skb, const struct nf_conn *ct,
 	/* Called from the helper function, this call never fails */
 	help = nfct_help(ct);
 
-	/* rcu_read_lock()ed by nf_hook_slow */
+	/* rcu_read_lock()ed by nf_hook_thresh */
 	helper = rcu_dereference(help->helper);
 
 	nf_log_packet(nf_ct_net(ct), nf_ct_l3num(ct), 0, skb, NULL, NULL, NULL,

@@ -43,7 +43,7 @@ nfnl_userspace_cthelper(struct sk_buff *skb, unsigned int protoff,
 	if (help == NULL)
 		return NF_DROP;
 
-	/* rcu_read_lock()ed by nf_hook_slow */
+	/* rcu_read_lock()ed by nf_hook_thresh */
 	helper = rcu_dereference(help->helper);
 	if (helper == NULL)
 		return NF_DROP;

@@ -442,7 +442,8 @@ __build_packet_message(struct nfnl_log_net *log,
 			if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSINDEV,
 					 htonl(indev->ifindex)) ||
 			/* this is the bridge group "brX" */
-			/* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
+			/* rcu_read_lock()ed by nf_hook_thresh or
+			 * nf_log_packet */
 			    nla_put_be32(inst->skb, NFULA_IFINDEX_INDEV,
 					 htonl(br_port_get_rcu(indev)->br->dev->ifindex)))
 				goto nla_put_failure;

@@ -477,7 +478,8 @@ __build_packet_message(struct nfnl_log_net *log,
 			if (nla_put_be32(inst->skb, NFULA_IFINDEX_PHYSOUTDEV,
 					 htonl(outdev->ifindex)) ||
 			/* this is the bridge group "brX" */
-			/* rcu_read_lock()ed by nf_hook_slow or nf_log_packet */
+			/* rcu_read_lock()ed by nf_hook_thresh or
+			 * nf_log_packet */
 			    nla_put_be32(inst->skb, NFULA_IFINDEX_OUTDEV,
 					 htonl(br_port_get_rcu(outdev)->br->dev->ifindex)))
 				goto nla_put_failure;

@@ -740,7 +740,7 @@ nfqnl_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum)
 	struct net *net = entry->state.net;
 	struct nfnl_queue_net *q = nfnl_queue_pernet(net);
 
-	/* rcu_read_lock()ed by nf_hook_slow() */
+	/* rcu_read_lock()ed by nf_hook_thresh */
 	queue = instance_lookup(q, queuenum);
 	if (!queue)
 		return -ESRCH;

@@ -41,7 +41,7 @@ helper_mt(const struct sk_buff *skb, struct xt_action_param *par)
 	if (!master_help)
 		return ret;
 
-	/* rcu_read_lock()ed by nf_hook_slow */
+	/* rcu_read_lock()ed by nf_hook_thresh */
 	helper = rcu_dereference(master_help->helper);
 	if (!helper)
 		return ret;

@@ -89,6 +89,11 @@ int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg)
 	struct nf_hook_entry *entry;
 	struct nf_hook_ops *elem;
 
+	if (reg->pf == NFPROTO_NETDEV &&
+	    (reg->hooknum != NF_NETDEV_INGRESS ||
+	     !reg->dev || dev_net(reg->dev) != net))
+		return -EINVAL;
+
 	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
 	if (!entry)
 		return -ENOMEM;

@@ -22,10 +22,10 @@ struct nf_queue_entry {
 
 /* Packet queuing */
 struct nf_queue_handler {
-	int			(*outfn)(struct nf_queue_entry *entry,
-					 unsigned int queuenum);
-	void			(*nf_hook_drop)(struct net *net,
-						struct nf_hook_ops *ops);
+	int		(*outfn)(struct nf_queue_entry *entry,
+				 unsigned int queuenum);
+	void		(*nf_hook_drop)(struct net *net,
+					struct nf_hook_ops *ops);
 };
 
 void nf_register_queue_handler(struct net *net, const struct nf_queue_handler *qh);