1 files changed, 61 insertions, 48 deletions

diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 9979f46c81dc..01130392b7c0 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -56,6 +56,8 @@
 #include <net/netfilter/nf_nat_helper.h>
 #include <net/netns/hash.h>
 
+#include "nf_internals.h"
+
 #define NF_CONNTRACK_VERSION	"0.5.0"
 
 int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct,
@@ -96,19 +98,26 @@ static struct conntrack_gc_work conntrack_gc_work;
 
 void nf_conntrack_lock(spinlock_t *lock) __acquires(lock)
 {
+	/* 1) Acquire the lock */
 	spin_lock(lock);
-	while (unlikely(nf_conntrack_locks_all)) {
-		spin_unlock(lock);
 
-		/*
-		 * Order the 'nf_conntrack_locks_all' load vs. the
-		 * spin_unlock_wait() loads below, to ensure
-		 * that 'nf_conntrack_locks_all_lock' is indeed held:
-		 */
-		smp_rmb(); /* spin_lock(&nf_conntrack_locks_all_lock) */
-		spin_unlock_wait(&nf_conntrack_locks_all_lock);
-		spin_lock(lock);
-	}
+	/* 2) read nf_conntrack_locks_all, with ACQUIRE semantics
+	 * It pairs with the smp_store_release() in nf_conntrack_all_unlock()
+	 */
+	if (likely(smp_load_acquire(&nf_conntrack_locks_all) == false))
+		return;
+
+	/* fast path failed, unlock */
+	spin_unlock(lock);
+
+	/* Slow path 1) get global lock */
+	spin_lock(&nf_conntrack_locks_all_lock);
+
+	/* Slow path 2) get the lock we want */
+	spin_lock(lock);
+
+	/* Slow path 3) release the global lock */
+	spin_unlock(&nf_conntrack_locks_all_lock);
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
 
@@ -149,28 +158,27 @@ static void nf_conntrack_all_lock(void)
 	int i;
 
 	spin_lock(&nf_conntrack_locks_all_lock);
-	nf_conntrack_locks_all = true;
 
-	/*
-	 * Order the above store of 'nf_conntrack_locks_all' against
-	 * the spin_unlock_wait() loads below, such that if
-	 * nf_conntrack_lock() observes 'nf_conntrack_locks_all'
-	 * we must observe nf_conntrack_locks[] held:
-	 */
-	smp_mb(); /* spin_lock(&nf_conntrack_locks_all_lock) */
+	nf_conntrack_locks_all = true;
 
 	for (i = 0; i < CONNTRACK_LOCKS; i++) {
-		spin_unlock_wait(&nf_conntrack_locks[i]);
+		spin_lock(&nf_conntrack_locks[i]);
+
+		/* This spin_unlock provides the "release" to ensure that
+		 * nf_conntrack_locks_all==true is visible to everyone that
+		 * acquired spin_lock(&nf_conntrack_locks[]).
+		 */
+		spin_unlock(&nf_conntrack_locks[i]);
 	}
 }
 
 static void nf_conntrack_all_unlock(void)
 {
-	/*
-	 * All prior stores must be complete before we clear
+	/* All prior stores must be complete before we clear
 	 * 'nf_conntrack_locks_all'. Otherwise nf_conntrack_lock()
 	 * might observe the false value but not the entire
-	 * critical section:
+	 * critical section.
+	 * It pairs with the smp_load_acquire() in nf_conntrack_lock()
 	 */
 	smp_store_release(&nf_conntrack_locks_all, false);
 	spin_unlock(&nf_conntrack_locks_all_lock);
@@ -248,8 +256,8 @@ bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
 		       u_int16_t l3num,
 		       struct net *net, struct nf_conntrack_tuple *tuple)
 {
-	struct nf_conntrack_l3proto *l3proto;
-	struct nf_conntrack_l4proto *l4proto;
+	const struct nf_conntrack_l3proto *l3proto;
+	const struct nf_conntrack_l4proto *l4proto;
 	unsigned int protoff;
 	u_int8_t protonum;
 	int ret;
@@ -398,22 +406,19 @@ static void
 destroy_conntrack(struct nf_conntrack *nfct)
 {
 	struct nf_conn *ct = (struct nf_conn *)nfct;
-	struct nf_conntrack_l4proto *l4proto;
+	const struct nf_conntrack_l4proto *l4proto;
 
 	pr_debug("destroy_conntrack(%p)\n", ct);
-	NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
+	WARN_ON(atomic_read(&nfct->use) != 0);
 
 	if (unlikely(nf_ct_is_template(ct))) {
 		nf_ct_tmpl_free(ct);
 		return;
 	}
-	rcu_read_lock();
 	l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
 	if (l4proto->destroy)
 		l4proto->destroy(ct);
 
-	rcu_read_unlock();
-
 	local_bh_disable();
 	/* Expectations will have been removed in clean_from_lists,
 	 * except TFTP can create an expectation on the first packet,
@@ -695,7 +700,7 @@ static int nf_ct_resolve_clash(struct net *net, struct sk_buff *skb,
 {
 	/* This is the conntrack entry already in hashes that won race. */
 	struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
-	struct nf_conntrack_l4proto *l4proto;
+	const struct nf_conntrack_l4proto *l4proto;
 
 	l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
 	if (l4proto->allow_clash &&
@@ -757,12 +762,11 @@ __nf_conntrack_confirm(struct sk_buff *skb)
 	 * connections for unconfirmed conns.  But packet copies and
 	 * REJECT will give spurious warnings here.
 	 */
-	/* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */
 
 	/* No external references means no one else could have
 	 * confirmed us.
 	 */
-	NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
+	WARN_ON(nf_ct_is_confirmed(ct));
 	pr_debug("Confirming conntrack %p\n", ct);
 	/* We have to check the DYING flag after unlink to prevent
 	 * a race against nf_ct_get_next_corpse() possibly called from
@@ -1084,7 +1088,7 @@ static void gc_worker(struct work_struct *work)
 
 static void conntrack_gc_work_init(struct conntrack_gc_work *gc_work)
 {
-	INIT_DELAYED_WORK(&gc_work->dwork, gc_worker);
+	INIT_DEFERRABLE_WORK(&gc_work->dwork, gc_worker);
 	gc_work->next_gc_run = HZ;
 	gc_work->exiting = false;
 }
@@ -1161,7 +1165,7 @@ void nf_conntrack_free(struct nf_conn *ct)
 	/* A freed object has refcnt == 0, that's
 	 * the golden rule for SLAB_TYPESAFE_BY_RCU
 	 */
-	NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 0);
+	WARN_ON(atomic_read(&ct->ct_general.use) != 0);
 
 	nf_ct_ext_destroy(ct);
 	nf_ct_ext_free(ct);
@@ -1177,8 +1181,8 @@ EXPORT_SYMBOL_GPL(nf_conntrack_free);
 static noinline struct nf_conntrack_tuple_hash *
 init_conntrack(struct net *net, struct nf_conn *tmpl,
 	       const struct nf_conntrack_tuple *tuple,
-	       struct nf_conntrack_l3proto *l3proto,
-	       struct nf_conntrack_l4proto *l4proto,
+	       const struct nf_conntrack_l3proto *l3proto,
+	       const struct nf_conntrack_l4proto *l4proto,
 	       struct sk_buff *skb,
 	       unsigned int dataoff, u32 hash)
 {
@@ -1289,8 +1293,8 @@ resolve_normal_ct(struct net *net, struct nf_conn *tmpl,
 		  unsigned int dataoff,
 		  u_int16_t l3num,
 		  u_int8_t protonum,
-		  struct nf_conntrack_l3proto *l3proto,
-		  struct nf_conntrack_l4proto *l4proto)
+		  const struct nf_conntrack_l3proto *l3proto,
+		  const struct nf_conntrack_l4proto *l4proto)
 {
 	const struct nf_conntrack_zone *zone;
 	struct nf_conntrack_tuple tuple;
@@ -1345,10 +1349,10 @@ unsigned int
 nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
 		struct sk_buff *skb)
 {
+	const struct nf_conntrack_l3proto *l3proto;
+	const struct nf_conntrack_l4proto *l4proto;
 	struct nf_conn *ct, *tmpl;
 	enum ip_conntrack_info ctinfo;
-	struct nf_conntrack_l3proto *l3proto;
-	struct nf_conntrack_l4proto *l4proto;
 	unsigned int *timeouts;
 	unsigned int dataoff;
 	u_int8_t protonum;
@@ -1415,7 +1419,7 @@ repeat:
 	/* Decide what timeout policy we want to apply to this flow. */
 	timeouts = nf_ct_timeout_lookup(net, ct, l4proto);
 
-	ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum, timeouts);
+	ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, timeouts);
 	if (ret <= 0) {
 		/* Invalid: inverse of the return code tells
 		 * the netfilter core what to do */
@@ -1469,7 +1473,7 @@ void nf_conntrack_alter_reply(struct nf_conn *ct,
 	struct nf_conn_help *help = nfct_help(ct);
 
 	/* Should be unconfirmed, so not in hash table yet */
-	NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
+	WARN_ON(nf_ct_is_confirmed(ct));
 
 	pr_debug("Altering reply tuple of %p to ", ct);
 	nf_ct_dump_tuple(newreply);
@@ -1491,7 +1495,7 @@ void __nf_ct_refresh_acct(struct nf_conn *ct,
 			  unsigned long extra_jiffies,
 			  int do_acct)
 {
-	NF_CT_ASSERT(skb);
+	WARN_ON(!skb);
 
 	/* Only update if this is not a fixed timeout */
 	if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
@@ -1689,6 +1693,18 @@ __nf_ct_unconfirmed_destroy(struct net *net)
 	}
 }
 
+void nf_ct_unconfirmed_destroy(struct net *net)
+{
+	might_sleep();
+
+	if (atomic_read(&net->ct.count) > 0) {
+		__nf_ct_unconfirmed_destroy(net);
+		nf_queue_nf_hook_drop(net);
+		synchronize_net();
+	}
+}
+EXPORT_SYMBOL_GPL(nf_ct_unconfirmed_destroy);
+
 void nf_ct_iterate_cleanup_net(struct net *net,
 			       int (*iter)(struct nf_conn *i, void *data),
 			       void *data, u32 portid, int report)
@@ -1700,14 +1716,10 @@ void nf_ct_iterate_cleanup_net(struct net *net,
 	if (atomic_read(&net->ct.count) == 0)
 		return;
 
-	__nf_ct_unconfirmed_destroy(net);
-
 	d.iter = iter;
 	d.data = data;
 	d.net = net;
 
-	synchronize_net();
-
 	nf_ct_iterate_cleanup(iter_net_only, &d, portid, report);
 }
 EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup_net);
@@ -1733,6 +1745,7 @@ nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data), void *data)
 		if (atomic_read(&net->ct.count) == 0)
 			continue;
 		__nf_ct_unconfirmed_destroy(net);
+		nf_queue_nf_hook_drop(net);
 	}
 	rtnl_unlock();