Merge branch 'possible_net_t'

Eric W. Biederman says: ==================== Introduce possible_net_t The current usage of write_pnet and read_pnet is a little laborious and error prone as you only notice if you failed to include them if are compiling with network namespaces enabled. possible_net_t remedies that by using a type that is 0 bytes when network namespaces are disabled and can only be read and written to with read_pnet and write_pnet. Aka less work and safer for the same effect. I kill hold_net and release_net first as are they are haven't been used since 2008 and are noise at the points where write_pnet and read_pnet are used. I have folded in Eric Dumazets suggestions to improve the killing of hold_net and release net. And respon. I had to respin anyway as there was enough changes elsewhere in the tree the previous version of these patches did not quite apply cleanly. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
mariux64 · Mar 12, 2015 · 20453d8 · 20453d8
2 parents 6c7005f + 0c5c9fb
commit 20453d8
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Showing 27 changed files with 49 additions and 155 deletions.
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
@@ -1721,9 +1721,7 @@ struct net_device {
 	struct netpoll_info __rcu	*npinfo;
 #endif
 
-#ifdef CONFIG_NET_NS
-	struct net		*nd_net;
-#endif
+	possible_net_t			nd_net;
 
 	/* mid-layer private */
 	union {
@@ -1863,10 +1861,7 @@ struct net *dev_net(const struct net_device *dev)
 static inline
 void dev_net_set(struct net_device *dev, struct net *net)
 {
-#ifdef CONFIG_NET_NS
-	release_net(dev->nd_net);
-	dev->nd_net = hold_net(net);
-#endif
+	write_pnet(&dev->nd_net, net);
 }
 
 static inline bool netdev_uses_dsa(struct net_device *dev)

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
@@ -3183,10 +3183,8 @@ struct wiphy {
 	const struct ieee80211_ht_cap *ht_capa_mod_mask;
 	const struct ieee80211_vht_cap *vht_capa_mod_mask;
 
-#ifdef CONFIG_NET_NS
 	/* the network namespace this phy lives in currently */
-	struct net *_net;
-#endif
+	possible_net_t _net;
 
 #ifdef CONFIG_CFG80211_WEXT
 	const struct iw_handler_def *wext;

diff --git a/include/net/fib_rules.h b/include/net/fib_rules.h
@@ -95,17 +95,10 @@ static inline void fib_rule_get(struct fib_rule *rule)
 	atomic_inc(&rule->refcnt);
 }
 
-static inline void fib_rule_put_rcu(struct rcu_head *head)
-{
-	struct fib_rule *rule = container_of(head, struct fib_rule, rcu);
-	release_net(rule->fr_net);
-	kfree(rule);
-}
-
 static inline void fib_rule_put(struct fib_rule *rule)
 {
 	if (atomic_dec_and_test(&rule->refcnt))
-		call_rcu(&rule->rcu, fib_rule_put_rcu);
+		kfree_rcu(rule, rcu);
 }
 
 static inline u32 frh_get_table(struct fib_rule_hdr *frh, struct nlattr **nla)

diff --git a/include/net/genetlink.h b/include/net/genetlink.h
@@ -92,9 +92,7 @@ struct genl_info {
 	struct genlmsghdr *	genlhdr;
 	void *			userhdr;
 	struct nlattr **	attrs;
-#ifdef CONFIG_NET_NS
-	struct net *		_net;
-#endif
+	possible_net_t		_net;
 	void *			user_ptr[2];
 	struct sock *		dst_sk;
 };

diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
@@ -76,9 +76,7 @@ struct inet_ehash_bucket {
  * ports are created in O(1) time?  I thought so. ;-)	-DaveM
  */
 struct inet_bind_bucket {
-#ifdef CONFIG_NET_NS
-	struct net		*ib_net;
-#endif
+	possible_net_t		ib_net;
 	unsigned short		port;
 	signed char		fastreuse;
 	signed char		fastreuseport;

diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
@@ -47,13 +47,13 @@ static inline struct net *skb_net(const struct sk_buff *skb)
 	 * Start with the most likely hit
 	 * End with BUG
 	 */
-	if (likely(skb->dev && skb->dev->nd_net))
+	if (likely(skb->dev && dev_net(skb->dev)))
 		return dev_net(skb->dev);
 	if (skb_dst(skb) && skb_dst(skb)->dev)
 		return dev_net(skb_dst(skb)->dev);
 	WARN(skb->sk, "Maybe skb_sknet should be used in %s() at line:%d\n",
 		      __func__, __LINE__);
-	if (likely(skb->sk && skb->sk->sk_net))
+	if (likely(skb->sk && sock_net(skb->sk)))
 		return sock_net(skb->sk);
 	pr_err("There is no net ptr to find in the skb in %s() line:%d\n",
 		__func__, __LINE__);
@@ -71,11 +71,11 @@ static inline struct net *skb_sknet(const struct sk_buff *skb)
 #ifdef CONFIG_NET_NS
 #ifdef CONFIG_IP_VS_DEBUG
 	/* Start with the most likely hit */
-	if (likely(skb->sk && skb->sk->sk_net))
+	if (likely(skb->sk && sock_net(skb->sk)))
 		return sock_net(skb->sk);
 	WARN(skb->dev, "Maybe skb_net should be used instead in %s() line:%d\n",
 		       __func__, __LINE__);
-	if (likely(skb->dev && skb->dev->nd_net))
+	if (likely(skb->dev && dev_net(skb->dev)))
 		return dev_net(skb->dev);
 	pr_err("There is no net ptr to find in the skb in %s() line:%d\n",
 		__func__, __LINE__);

diff --git a/include/net/neighbour.h b/include/net/neighbour.h
@@ -65,9 +65,7 @@ enum {
 };
 
 struct neigh_parms {
-#ifdef CONFIG_NET_NS
-	struct net *net;
-#endif
+	possible_net_t net;
 	struct net_device *dev;
 	struct list_head list;
 	int	(*neigh_setup)(struct neighbour *);
@@ -167,9 +165,7 @@ struct neigh_ops {
 
 struct pneigh_entry {
 	struct pneigh_entry	*next;
-#ifdef CONFIG_NET_NS
-	struct net		*net;
-#endif
+	possible_net_t		net;
 	struct net_device	*dev;
 	u8			flags;
 	u8			key[0];

diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
@@ -49,11 +49,6 @@ struct net {
 	atomic_t		count;		/* To decided when the network
 						 *  namespace should be shut down.
 						 */
-#ifdef NETNS_REFCNT_DEBUG
-	atomic_t		use_count;	/* To track references we
-						 * destroy on demand
-						 */
-#endif
 	spinlock_t		rules_mod_lock;
 
 	atomic64_t		cookie_gen;
@@ -236,48 +231,27 @@ int net_eq(const struct net *net1, const struct net *net2)
 #endif
 
 
-#ifdef NETNS_REFCNT_DEBUG
-static inline struct net *hold_net(struct net *net)
-{
-	if (net)
-		atomic_inc(&net->use_count);
-	return net;
-}
-
-static inline void release_net(struct net *net)
-{
-	if (net)
-		atomic_dec(&net->use_count);
-}
-#else
-static inline struct net *hold_net(struct net *net)
-{
-	return net;
-}
-
-static inline void release_net(struct net *net)
-{
-}
-#endif
-
+typedef struct {
 #ifdef CONFIG_NET_NS
+	struct net *net;
+#endif
+} possible_net_t;
 
-static inline void write_pnet(struct net **pnet, struct net *net)
+static inline void write_pnet(possible_net_t *pnet, struct net *net)
 {
-	*pnet = net;
+#ifdef CONFIG_NET_NS
+	pnet->net = net;
+#endif
 }
 
-static inline struct net *read_pnet(struct net * const *pnet)
+static inline struct net *read_pnet(const possible_net_t *pnet)
 {
-	return *pnet;
-}
-
+#ifdef CONFIG_NET_NS
+	return pnet->net;
 #else
-
-#define write_pnet(pnet, net)	do { (void)(net);} while (0)
-#define read_pnet(pnet)		(&init_net)
-
+	return &init_net;
 #endif
+}
 
 #define for_each_net(VAR)				\
 	list_for_each_entry(VAR, &net_namespace_list, list)

diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
@@ -95,9 +95,8 @@ struct nf_conn {
 	/* Timer function; drops refcnt when it goes off. */
 	struct timer_list timeout;
 
-#ifdef CONFIG_NET_NS
-	struct net *ct_net;
-#endif
+	possible_net_t ct_net;
+
 	/* all members below initialized via memset */
 	u8 __nfct_init_offset[0];
 

diff --git a/include/net/sock.h b/include/net/sock.h
@@ -190,9 +190,7 @@ struct sock_common {
 		struct hlist_nulls_node skc_portaddr_node;
 	};
 	struct proto		*skc_prot;
-#ifdef CONFIG_NET_NS
-	struct net	 	*skc_net;
-#endif
+	possible_net_t		skc_net;
 
 #if IS_ENABLED(CONFIG_IPV6)
 	struct in6_addr		skc_v6_daddr;
@@ -2204,7 +2202,7 @@ static inline void sk_change_net(struct sock *sk, struct net *net)
 
 	if (!net_eq(current_net, net)) {
 		put_net(current_net);
-		sock_net_set(sk, hold_net(net));
+		sock_net_set(sk, net);
 	}
 }
 

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
@@ -126,9 +126,7 @@ struct xfrm_state_walk {
 
 /* Full description of state of transformer. */
 struct xfrm_state {
-#ifdef CONFIG_NET_NS
-	struct net		*xs_net;
-#endif
+	possible_net_t		xs_net;
 	union {
 		struct hlist_node	gclist;
 		struct hlist_node	bydst;
@@ -522,9 +520,7 @@ struct xfrm_policy_queue {
 };
 
 struct xfrm_policy {
-#ifdef CONFIG_NET_NS
-	struct net		*xp_net;
-#endif
+	possible_net_t		xp_net;
 	struct hlist_node	bydst;
 	struct hlist_node	byidx;
 

diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
@@ -940,7 +940,7 @@ p9_fd_create_tcp(struct p9_client *client, const char *addr, char *args)
 	sin_server.sin_family = AF_INET;
 	sin_server.sin_addr.s_addr = in_aton(addr);
 	sin_server.sin_port = htons(opts.port);
-	err = __sock_create(read_pnet(&current->nsproxy->net_ns), PF_INET,
+	err = __sock_create(current->nsproxy->net_ns, PF_INET,
 			    SOCK_STREAM, IPPROTO_TCP, &csocket, 1);
 	if (err) {
 		pr_err("%s (%d): problem creating socket\n",
@@ -988,7 +988,7 @@ p9_fd_create_unix(struct p9_client *client, const char *addr, char *args)
 
 	sun_server.sun_family = PF_UNIX;
 	strcpy(sun_server.sun_path, addr);
-	err = __sock_create(read_pnet(&current->nsproxy->net_ns), PF_UNIX,
+	err = __sock_create(current->nsproxy->net_ns, PF_UNIX,
 			    SOCK_STREAM, 0, &csocket, 1);
 	if (err < 0) {
 		pr_err("%s (%d): problem creating socket\n",

diff --git a/net/core/dev.c b/net/core/dev.c
@@ -6841,8 +6841,6 @@ void free_netdev(struct net_device *dev)
 {
 	struct napi_struct *p, *n;
 
-	release_net(dev_net(dev));
-
 	netif_free_tx_queues(dev);
 #ifdef CONFIG_SYSFS
 	kvfree(dev->_rx);

diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
@@ -31,7 +31,7 @@ int fib_default_rule_add(struct fib_rules_ops *ops,
 	r->pref = pref;
 	r->table = table;
 	r->flags = flags;
-	r->fr_net = hold_net(ops->fro_net);
+	r->fr_net = ops->fro_net;
 
 	r->suppress_prefixlen = -1;
 	r->suppress_ifgroup = -1;
@@ -116,7 +116,6 @@ static int __fib_rules_register(struct fib_rules_ops *ops)
 		if (ops->family == o->family)
 			goto errout;
 
-	hold_net(net);
 	list_add_tail_rcu(&ops->list, &net->rules_ops);
 	err = 0;
 errout:
@@ -160,15 +159,6 @@ static void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
 	}
 }
 
-static void fib_rules_put_rcu(struct rcu_head *head)
-{
-	struct fib_rules_ops *ops = container_of(head, struct fib_rules_ops, rcu);
-	struct net *net = ops->fro_net;
-
-	release_net(net);
-	kfree(ops);
-}
-
 void fib_rules_unregister(struct fib_rules_ops *ops)
 {
 	struct net *net = ops->fro_net;
@@ -178,7 +168,7 @@ void fib_rules_unregister(struct fib_rules_ops *ops)
 	fib_rules_cleanup_ops(ops);
 	spin_unlock(&net->rules_mod_lock);
 
-	call_rcu(&ops->rcu, fib_rules_put_rcu);
+	kfree_rcu(ops, rcu);
 }
 EXPORT_SYMBOL_GPL(fib_rules_unregister);
 
@@ -303,7 +293,7 @@ static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh)
 		err = -ENOMEM;
 		goto errout;
 	}
-	rule->fr_net = hold_net(net);
+	rule->fr_net = net;
 
 	if (tb[FRA_PRIORITY])
 		rule->pref = nla_get_u32(tb[FRA_PRIORITY]);
@@ -423,7 +413,6 @@ static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh)
 	return 0;
 
 errout_free:
-	release_net(rule->fr_net);
 	kfree(rule);
 errout:
 	rules_ops_put(ops);

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
@@ -591,7 +591,7 @@ struct pneigh_entry * pneigh_lookup(struct neigh_table *tbl,
 	if (!n)
 		goto out;
 
-	write_pnet(&n->net, hold_net(net));
+	write_pnet(&n->net, net);
 	memcpy(n->key, pkey, key_len);
 	n->dev = dev;
 	if (dev)
@@ -600,7 +600,6 @@ struct pneigh_entry * pneigh_lookup(struct neigh_table *tbl,
 	if (tbl->pconstructor && tbl->pconstructor(n)) {
 		if (dev)
 			dev_put(dev);
-		release_net(net);
 		kfree(n);
 		n = NULL;
 		goto out;
@@ -634,7 +633,6 @@ int pneigh_delete(struct neigh_table *tbl, struct net *net, const void *pkey,
 				tbl->pdestructor(n);
 			if (n->dev)
 				dev_put(n->dev);
-			release_net(pneigh_net(n));
 			kfree(n);
 			return 0;
 		}
@@ -657,7 +655,6 @@ static int pneigh_ifdown(struct neigh_table *tbl, struct net_device *dev)
 					tbl->pdestructor(n);
 				if (n->dev)
 					dev_put(n->dev);
-				release_net(pneigh_net(n));
 				kfree(n);
 				continue;
 			}
@@ -1428,11 +1425,10 @@ struct neigh_parms *neigh_parms_alloc(struct net_device *dev,
 				neigh_rand_reach_time(NEIGH_VAR(p, BASE_REACHABLE_TIME));
 		dev_hold(dev);
 		p->dev = dev;
-		write_pnet(&p->net, hold_net(net));
+		write_pnet(&p->net, net);
 		p->sysctl_table = NULL;
 
 		if (ops->ndo_neigh_setup && ops->ndo_neigh_setup(dev, p)) {
-			release_net(net);
 			dev_put(dev);
 			kfree(p);
 			return NULL;
@@ -1472,7 +1468,6 @@ EXPORT_SYMBOL(neigh_parms_release);
 
 static void neigh_parms_destroy(struct neigh_parms *parms)
 {
-	release_net(neigh_parms_net(parms));
 	kfree(parms);
 }